Bushland Weeds Manual - Environmental Weeds Action Network
Bushland Weeds Manual - Environmental Weeds Action Network
Bushland Weeds Manual - Environmental Weeds Action Network
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<strong>Bushland</strong><br />
<strong>Weeds</strong><br />
A practical guide to their management<br />
With case studies from the Swan Coastal Plain and beyond<br />
Kate Brown and Kris Brooks<br />
Illustrated by Libby Sandiford
Published by and available from <strong>Environmental</strong> <strong>Weeds</strong> <strong>Action</strong> <strong>Network</strong> (Inc), PO Box 380 Greenwood, 6924, Australia.<br />
www.iinet.net.au\~ewan<br />
© Individual artists for photographs and drawings<br />
© <strong>Environmental</strong> <strong>Weeds</strong> <strong>Action</strong> <strong>Network</strong> (Inc)<br />
Parts of this publication may be reproduced for educational purposes with appropriate acknowledgment. A copy of any<br />
report or publication using these materials should be lodged with the <strong>Environmental</strong> <strong>Weeds</strong> <strong>Action</strong> <strong>Network</strong> (Inc).<br />
National Library of Australia Cataloguing-in-publication entry<br />
ISBN 0 9579001 1 2.<br />
Disclaimer Any recommendations in this book do not necessarily represent the policy or support of the sponsoring<br />
organisations. This book is intended as a source of information only. People should obtain independent advice before acting<br />
on information in this publication. It is the user’s responsibility to ensure that any methodology adopted or adapted from this<br />
book is suitable for the purposes intended. Read the label of herbicides for further information and registration status.<br />
Consult the NRA website www.nra.gov.au to determine the status of permits for your situation or state. The publisher or the<br />
authors do not accept liability however arising, including liability for negligence, or for any loss resulting from the use of or<br />
reliance upon information in this book.<br />
Design, typesetting and print management by West Print Management, Mosman Park, Perth, Western Australia<br />
Cover photograph by Kate Brown – Late spring in the shrublands at Brixton Street Wetlands with Pink Feather Flower<br />
(Verticordia densiflora), Kunzea (Kunzea micrantha) and Purple Flag (Patersonia aff. occidentalis) in full flower.<br />
Cover illustrations by Libby Sandiford – Some of the weeds starting to invade the Wetlands: From left to right; Harlequin<br />
Flower (Sparaxis bulbifera), Black Flag (Ferraria crispa), African Lovegrass (Eragrostis curvula) and Perennial Veldgrass<br />
(Ehrharta calycina).
Acknowledgments<br />
This manual is the culmination of a five year project that has been supported by the <strong>Environmental</strong> <strong>Weeds</strong> <strong>Action</strong><br />
<strong>Network</strong>. The project would not have been possible without the ongoing support of project manager, Margo<br />
O’Byrne, and the project team Bob Dixon, Rod Randall and the extraordinary financial manager, Gary Matthews. Liz<br />
Western generously stood in as manager for a year, supervising the project while Margo was away. Peter Nash and<br />
Patrick Piggott also contributed to project management. The Swan Catchment Centre provided office space and<br />
administrative support for three years. Sally Madden and Simone Tuten provided technical support in the early<br />
stages of the project.<br />
Production of the manual has been a collective effort. Kate Brown wrote the chapters on the project, managing<br />
weeds in bushland, the geophyte weeds, the other herbaceous weeds and with Kris Brooks, the mapping<br />
guidelines. Kris Brooks wrote the grasses, the woody weeds and the herbicides in bushland chapters. The maps<br />
were compiled by Kris Brooks and Kate Brown.<br />
Richard Groves, John Moore, Margo O’Byrne and Rod Randall provided valuable comments on various drafts, Bob<br />
Dixon on the woody weeds chapter and Bronwen Keighery the managing weeds in bushland chapter. Their<br />
comments greatly improved the final manuscript. Neil Gibson, Richard Groves and Janice Marshall proof read and<br />
provided comments on the final document.<br />
Throughout the project Greg Keighery, Bob Dixon, John Moore and John Peirce have generously shared their<br />
knowledge of bushland weeds with us. They also provided much of the information in the weed management tables.<br />
Community volunteers and Friends groups carried out much of the weed management work that forms the basis of<br />
case studies outlined in the manual. They also helped us map weeds, set up trials and collect data. We would like to<br />
thank The Friends of Shenton <strong>Bushland</strong>, in particular Janice Marshall and Dani Boase-Jelinek, Friends of Blue Gum<br />
Lake especially Marian Watson, Friends of Brixton Street Wetlands particularly Regina Drummond, Trevor<br />
Drummond, Nick Buters and Elizabeth Buters, Friends of Gingin Brook in particular Richard Diggins and Pauline<br />
Diggins, and Friends of Talbot Road Reserve, especially Mark Gloyn and Helen Gardiner.<br />
John Carter and Robyn Phillimore from Department of Conservation and Land Management, Grant McKinnon from<br />
the City of Swan, Wayne van Lieven from the City of Gosnells, Graznya Packowskya from the City of Melville and<br />
Steve McCabe from the City of Nedlands all went out of their way to provide invaluable on-ground support at<br />
bushlands under their management.<br />
The project was largely funded through a Natural Heritage Trust Grant, with the Lotteries Commission and the CRC<br />
for Weed Management also contributing.<br />
Kate Brown and Kris Brooks<br />
September 2002.<br />
All illustrations are by Libby Sandiford and all photographs by Kate Brown, unless otherwise noted.<br />
The <strong>Environmental</strong> <strong>Weeds</strong> <strong>Action</strong> <strong>Network</strong> (EWAN) is a community group formed in 1996 to:<br />
• Promote understanding of the threat of environmental weeds to bushland.<br />
• Provide information about weed control in native vegetation.<br />
• Convince governments at all levels of the need for appropriate legislation and funding for weed control.<br />
• Encourage research into methods of weed control.<br />
• Encourage community participation.<br />
i
Contents<br />
Introduction ....................................................................................................................................................................iv<br />
Chapter 1. The Project......................................................................................................................................................1<br />
Funding and administration..................................................................................................................................................1<br />
The sites ..................................................................................................................................................................................1<br />
Chapter 2. Managing <strong>Weeds</strong> in <strong>Bushland</strong>: Some General Principles............................................................................5<br />
Gathering area - specific information ..................................................................................................................................5<br />
Regional information..............................................................................................................................................................6<br />
Developing a weed management program..........................................................................................................................6<br />
Implementation – taking an integrated approach..............................................................................................................6<br />
Chapter 3. Grass <strong>Weeds</strong>....................................................................................................................................................9<br />
Impacts ....................................................................................................................................................................................9<br />
Biology – why are grasses successful weeds?..................................................................................................................11<br />
Management and Control ....................................................................................................................................................14<br />
Monitoring and follow-up ....................................................................................................................................................18<br />
Case Studies ..........................................................................................................................................................................19<br />
Weed management table – grasses ....................................................................................................................................28<br />
Chapter 4. Corms, Bulbs and Tubers: The <strong>Weeds</strong> that Die Back to Fleshy Underground Storage Organs ............32<br />
The underground storage organs; life-cycles and reproduction....................................................................................33<br />
Management and Control ....................................................................................................................................................39<br />
Key points..............................................................................................................................................................................42<br />
Case studies ..........................................................................................................................................................................44<br />
Weed management table – corms bulbs and tubers ......................................................................................................52<br />
Chapter 5. Broadleaf Herbs, Sedges and Succulents ..................................................................................................56<br />
Annual herbs ........................................................................................................................................................................56<br />
Perennial herbs ....................................................................................................................................................................59<br />
Case studies ..........................................................................................................................................................................60<br />
Weed management table – annual broadleaf herbs ........................................................................................................66<br />
Weed management table – perennial broadleaf herbs ....................................................................................................70<br />
Chapter 6. Trees, Shrubs and Climbers: The Woody <strong>Weeds</strong> ......................................................................................74<br />
Impacts ..................................................................................................................................................................................75<br />
Mechanisms of spread ........................................................................................................................................................75<br />
Resprouting, suckering and apical control ......................................................................................................................75<br />
Management and Control ....................................................................................................................................................76<br />
Case studies ..........................................................................................................................................................................84<br />
Weed management table – trees, shrubs and climbers ..................................................................................................86<br />
Chapter 7. Weed Mapping in Remnant <strong>Bushland</strong> ........................................................................................................90<br />
Equipment required ............................................................................................................................................................90<br />
What weeds to map?............................................................................................................................................................90<br />
Mapping in practice ............................................................................................................................................................91<br />
Using weed maps..................................................................................................................................................................91<br />
In conclusion ........................................................................................................................................................................93<br />
Chapter 8. Herbicide Use in <strong>Bushland</strong>..........................................................................................................................94<br />
Using herbicides in bushland ............................................................................................................................................94<br />
Duty of care ..........................................................................................................................................................................94<br />
Personal care ........................................................................................................................................................................94<br />
Training..................................................................................................................................................................................95<br />
Legislation ............................................................................................................................................................................96<br />
<strong>Bushland</strong> care ......................................................................................................................................................................96<br />
Using contractors ................................................................................................................................................................97<br />
Some herbicides used in bushland ....................................................................................................................................97<br />
Final note ......................................................................................................................................................................100<br />
Appendix 1: Herbicide spraying contract ..................................................................................................................101<br />
References ....................................................................................................................................................................102<br />
iii
iv<br />
Introduction<br />
The Banksia, Tuart and Jarrah woodlands, the<br />
shrublands and the species-rich heathlands of the Swan<br />
Coastal Plain and Darling Plateau are wonderful places.<br />
They contribute to Perth’s unique natural landscapes,<br />
provide a window into the natural world, habitat for<br />
native fauna and support an extraordinarily diverse<br />
flora. They are fast disappearing though, mostly under<br />
urban development. Those bushlands that remain face<br />
a range of threats; one of the most serious is invasion<br />
by environmental weeds.<br />
The concept of environmental weeds is still relatively<br />
new. Although the weediness of plants like Bridal<br />
Creeper and Watsonia have become entrenched in the<br />
public psyche, there is some way to go before the wider<br />
community accepts the extent of the problem. For<br />
example, Harlequin Flower (Sparaxis bulbifera) threatens<br />
one of the last remaining clay-based wetlands on the<br />
eastern side of the coastal plain and yet the species was<br />
available this year from a fundraising catalogue in at<br />
least one local primary school. Still, it is evident that<br />
many people do recognise the threats. Increasingly,<br />
community volunteers and state and local governments<br />
are involved in on-ground actions to protect bushland<br />
from the impacts of environmental weeds.<br />
With few resources available, maximising the positive<br />
outcomes of these professional and voluntary efforts is<br />
critical. For those working on the ground, information<br />
on identification and control is available from a number<br />
of good books: Managing Perth’s <strong>Bushland</strong>s (Scheltema<br />
and Harris 1995), Southern <strong>Weeds</strong> and their control<br />
(Moore and Wheeler 2002), Bush Invaders of South-East<br />
Australia (Muyt 2001), Western <strong>Weeds</strong>. A guide to the<br />
weeds of Western Australia (Hussey et al. 1997) and<br />
<strong>Environmental</strong> weeds: a field guide for SE Australia<br />
(Blood 2001). Importantly, this kind of information<br />
needs to be taken and applied in the context of<br />
particular bushland areas. There are no simple<br />
formulas and effective management begins with an<br />
understanding and a knowledge of each site.<br />
It was with this in mind that, in 1998, the <strong>Environmental</strong><br />
<strong>Weeds</strong> <strong>Action</strong> <strong>Network</strong> (EWAN), with funding from the<br />
Natural Heritage Trust, employed a project officer to<br />
work with community volunteers and local and state<br />
government land managers at bushland sites across<br />
Perth’s Swan Coastal Plain. The underlying objective<br />
was to help the various land managers to develop<br />
strategies for effective weed management in their<br />
bushlands. This manual has grown out of that project.<br />
The aim of the manual is firstly to bring together<br />
information on the biology and known control methods<br />
for the serious weeds of bushlands of the Swan Coastal<br />
Plain and Jarrah Forest. Secondly, it is to illustrate,<br />
with examples and case studies, how this sort of<br />
information can be used to manage weeds in the<br />
context of particular sites. Hopefully this will provide<br />
the reader with the basic knowledge and the<br />
framework needed to begin effectively managing the<br />
weeds in their own bushlands.<br />
Chapter one provides descriptions of bushlands from<br />
where the case studies and examples throughout the<br />
text are drawn. Chapter two covers some general<br />
principles that should guide weed management in<br />
bushland, including the kind of area-specific information<br />
required before setting weed management priorities.<br />
The next four chapters each cover a different group or<br />
lifeform of weeds. The first three groups are all herbs –<br />
green non-woody plants: Chapter three covers the<br />
grasses, chapter four herbs that die back to corms,<br />
bulbs or tubers over summer (geophytes) and chapter<br />
five broadleaf herbs, sedges and succulents. The final<br />
group, chapter six, includes all the woody plants and a<br />
few climbers that are technically herbs, but have<br />
control strategies in common with woody climbers.<br />
Individual chapters look at the general biology of each<br />
weed group and how it relates to dispersal, spread,<br />
control and management. Case studies examine control<br />
of certain species at particular sites and discuss the<br />
management approach taken. They often describe the<br />
set-up of trials and monitoring programs. Each weed<br />
group has a corresponding table containing a summary<br />
of information, gathered from a wide range of sources,<br />
on the biology and control of weeds occurring in<br />
bushland of the Swan Coastal Plain and Jarrah Forest.<br />
The list is based on ‘A Checklist of the naturalised<br />
vascular plants of Western Australia’ (Keighery 1999a)<br />
and includes species that can have an impact on<br />
biodiversity and hamper restoration and regeneration<br />
efforts. Finally there are chapters on how to map weed<br />
populations in urban bushland, an integral part of weed<br />
management and on the issues arising from the use of<br />
herbicides in bushland.<br />
Ideally, this manual will impart enough information for<br />
the reader to devise a strategy for management of their<br />
serious bushland weeds. At the same time the authors<br />
want to highlight the complexities involved in working<br />
in Perth’s bushlands; diverse and wonderful places to<br />
get to know and understand. The following chapter<br />
provides detailed descriptions of some of those<br />
bushlands along with the serious weeds that threaten<br />
them and the people who are managing them.
Over four years, project officers have been involved in<br />
work at a series of bushlands across the Swan Coastal<br />
Plain and one in Western Australian Wheatbelt. The<br />
major task over that time has been to work on site with<br />
those involved in weed management and bush<br />
regeneration, providing both on-ground and technical<br />
support. The idea was to select a series of sites that<br />
were representative of bushlands on a range of soils and<br />
land forms across the coastal plain, had regionally<br />
significant conservation values and were managed by<br />
people actively involved in on-ground works.<br />
The underlying objective has been to work with the<br />
bushland ‘managers’, whoever they were, to help them<br />
protect their bushland through carefully targeted and<br />
strategic weed management. Initially work involved<br />
identifying those weeds that were the greatest threats<br />
to the conservation values of each site, then mapping<br />
their distribution across the bushland. The greatest<br />
efforts have been directed to consistent management of<br />
these locally serious weeds, taking an integrated<br />
approach, addressing the causes of invasion and<br />
implementing a range of control strategies. Often trials<br />
had to be carried out to determine practical and<br />
effective methods. Project officers regularly worked<br />
alongside Friends groups, council bushland workers,<br />
and others who carried out on-ground works.<br />
Sometimes they facilitated the employment of<br />
contractors and often worked alongside them,<br />
supervising and guiding their work. At all sites<br />
monitoring was put in place to measure the<br />
effectiveness of control programs and the regeneration<br />
of native plant communities over time. For most<br />
bushlands, field herbaria of all weeds and some native<br />
species commonly mistaken for weeds were compiled.<br />
Funding and administration<br />
The project was funded through the Natural Heritage<br />
Trust and managed and administered by a voluntary<br />
steering committee made up of members of the<br />
<strong>Environmental</strong> <strong>Weeds</strong> <strong>Action</strong> <strong>Network</strong> (EWAN): Bob<br />
Dixon from Kings Park and Botanic Garden, Gary<br />
Matthews community volunteer and EWAN treasurer,<br />
Margo O’Byrne from the Department of <strong>Environmental</strong><br />
Protection and Rod Randall from the Western<br />
Australian Department of Agriculture.<br />
The sites<br />
Shenton <strong>Bushland</strong><br />
Shenton <strong>Bushland</strong>, a 21 hectare remnant of Banksia<br />
(Banksia menziesii, B. attenuata), Jarrah (Eucalyptus<br />
marginata) woodlands lies on Spearwood dunes<br />
approximately eight kilometres west of the centre of<br />
Perth. With only 18 % of the vegetation complex<br />
remaining uncleared the bushland is considered<br />
regionally significant (Government of Western Australia<br />
2000). These species-rich woodlands occur on pale<br />
yellow to grey calcareous sands derived from Tamala<br />
limestone. Rich in perennial herbs, Milkmaids<br />
(Burchardia congesta), Vanilla Lily (Sowerbaea laxiflora),<br />
Leafy Sundew (Drosera stolonifera), Yellow Autumn Lily<br />
(Tricoryne elatior) and the sedge Mesomelaena<br />
pseudostygia are common. The open sandy patches are<br />
Chapter 1 The Project<br />
often colonised by annual herbs such as Slender<br />
Podolepis (Podolepis gracilis) and after fire the annual<br />
grass, Austrostipa compressa is noticeable, flowering<br />
and seeding prolifically. Commonly occurring shrubs<br />
include Hairy Yellow Pea (Gompholobium tomentosum),<br />
Daviesia nudiflora and Grass Tree (Xanthorrhoea<br />
preissii). Around 120 species of natives (Marshall<br />
unpubl.) and 65 species of weeds (Brown and Brooks<br />
unpubl.) have been recorded. Approximately 50 % of<br />
the bushland is in good to excellent condition. The<br />
remainder varies from good to degraded with areas of<br />
severe localised disturbance (Ecoscape 1994,<br />
Government of Western Australia 2000).<br />
<strong>Weeds</strong> that threaten the undisturbed bushland include<br />
a number of South African geophytes (plants that die<br />
back to bulbs, corms or tubers each year), including<br />
Yellow Soldier (Lachenalia reflexa), Freesia (Freesia alba<br />
x leichtlinii), Watsonia (Watsonia meriana) and Black<br />
Flag (Ferraria crispa). The perennial herbs Geraldton<br />
Carnation Weed (Euphorbia terracina) and Rose<br />
Pelargonium (Pelargonium capitatum) are serious<br />
invaders and many weedy annuals are common,<br />
particularly in the highly disturbed areas. These<br />
include Flat Weed (Hypochaeris glabra), Ursinia (Ursinia<br />
anthemoides), French Catchfly (Silene gallica), and<br />
Slender Suckling Clover (Trifolium dubium). Perennial<br />
Veldgrass (Ehrharta calycina) is one of the most serious<br />
invaders of the bushland often establishing in<br />
previously intact areas following fire.<br />
For the last nine years on-ground management of<br />
Shenton <strong>Bushland</strong> has been carried out by The Friends<br />
of Shenton <strong>Bushland</strong> (Inc.), a community group formed<br />
after the bushland was saved from development in 1993.<br />
In 2000, following lobbying from community groups, a<br />
bushcare officer was employed to carry out on-ground<br />
management of bushlands within the City of Nedlands,<br />
including Shenton <strong>Bushland</strong>. In the past, much of the<br />
funding has come from government grants to the<br />
Friends. In recent times, however, the City of Nedlands<br />
has started to fund the continuation of works programs<br />
initiated through grant money. The Friends have a high<br />
level of input into management through organisation of<br />
works programs and supervision of contractors who do<br />
much of the weed management work.<br />
Friends of Shenton <strong>Bushland</strong> and volunteers hand-weeding Yellow<br />
Soldier in the Banksia woodland.<br />
1
2<br />
Chapter 1 The Project<br />
Blue Gum Lake Reserve<br />
Blue Gum Lake is part of a chain of wetlands that lie on<br />
the interface of the Bassendean and Spearwood dune<br />
systems. Flooded Gum (Eucalyptus rudis) – Swamp<br />
Banksia (Banksia littoralis) woodlands fringe the lake<br />
while Banksia attenuata, B. menziesii and B. ilicifolia<br />
woodlands occupy the drier uplands. Common in the<br />
understorey of the woodlands around the lake are<br />
Centella asiatica and Pale Rush (Juncus pallidus). The<br />
drier Banksia woodlands of the uplands are very<br />
species-rich, particularly in perennial herbs and<br />
shrubs. Phlebocarya ciliata, Prickly Conostylis<br />
(Conostylis aculeata) and Purple Flag (Patersonia<br />
occidentalis) are among the commonly occurring herbs<br />
and typical shrubs include Devils Pins (Hovea<br />
pungens), Rose Banjine (Pimelea rosea) and Pineapple<br />
Bush (Dasypogon bromeliifolius). The perennial native<br />
grass Microlaena stipoides occurs occasionally in the<br />
bushland and after fire the annual grass, Austrostipa<br />
compressa, is very common. Around 62 species of<br />
natives (City of Melville 1992) and 80 species of weeds<br />
(Brown and Brooks unpubl. data) have been recorded.<br />
Weed invasion is a major threat with around 40 % of<br />
the bushland suffering from severe disturbance.<br />
Serious weeds of the drier Banksia woodlands include<br />
Perennial Veldgrass and South African geophytes such<br />
as Freesia, Yellow Soldier and Black Flag. The Sydney<br />
Golden Wattle (Acacia longifolia) is a major weed of the<br />
fringing vegetation, as is Vasey Grass (Paspalum<br />
urvillei) and Kikuyu (Pennisetum clandestinum). One of<br />
the serious weed problems at the reserve has arisen<br />
from plantings of non-local species around and through<br />
the bushland. Many, including Sydney Golden Wattle,<br />
Melaleuca lineariifolia, River Red Gum (Eucalyptus<br />
camaldulensis) and Geraldton Wax (Chamelaucium<br />
uncinatum) have become naturalised in the bushland.<br />
Additional to this threat is the planting of species that<br />
occur naturally in the bushland but have been grown<br />
from seed collected a long way from the reserve. The<br />
early flowering shrub-form of Banksia menziesii, from<br />
the sand plains 200km to the north of Perth, has been<br />
Vegetation Profile of the Brixton Street Wetlands<br />
(Illustration by Margaret Pieroni: from Keighery et al. 1996)<br />
planted in the reserve. It makes a disturbing contrast<br />
to the later flowering form, a beautiful woodland tree<br />
that grows naturally around Blue Gum Lake. These<br />
plantings threaten the nature conservation values of<br />
the bushland as much as any South African invader.<br />
The Friends of Blue Gum Lake have played a major role<br />
in managing the bushland for many years. They are not<br />
an incorporated group and, accordingly, acquiring<br />
government grants is difficult. The little funding that is<br />
available for weed management work comes from the<br />
City of Melville. The City has two staff dedicated to onground<br />
bushland management activities. Their work is<br />
spread across the City’s many reserves. For herbicide<br />
spraying the City is often obliged to use ‘preferred<br />
contractors’.<br />
Brixton Street Wetlands<br />
The Brixton Street Wetlands lie 20 kilometres south east<br />
of Perth at the foot of the Darling Scarp. A small remnant<br />
(19 hectares) on the winter-wet flats of Guildford<br />
formation clays, the wetlands support many rare and<br />
restricted plant species as well as threatened plant<br />
communities. They also support an exceedingly diverse<br />
flora of 307 native taxa (Keighery and Keighery 1995).<br />
Most of the wetland soils are waterlogged through the<br />
winter months and deep pools form in clay<br />
depressions. When the pools are full they support a<br />
number of native aquatic plants but as water levels<br />
start to drop a series of annual and perennial herbs<br />
grow and flower. In late winter Flannel Flowers<br />
(Tribonanthes species), Blue Squill (Chamaescilla<br />
species) and Early Nancy (Wurmbea dioica) are<br />
flowering and by late spring Swamp Wallaby Grass<br />
(Amphibromus nervosus) is in abundance. By early<br />
summer the pools are dry and the claypans covered in<br />
Sundews (Drosera species) and Trigger Plants<br />
(Stylidium species). Slightly higher in the landscape, the<br />
flats surrounding the claypans also support a diverse<br />
range of native herbs, sedges and rushes. Shrubs,<br />
including Swish Bush (Viminaria juncea) and Feather<br />
Flowers (Verticordia species), are also common. On the<br />
sandy rises, Marri (Eucalyptus calophylla) woodlands<br />
occur and in spring, Red and Green Kangaroo Paw<br />
(Anigozanthos manglesii) flower throughout their<br />
understorey. With this kind of habitat almost entirely<br />
cleared on the Swan Coastal Plain the area is of<br />
outstanding conservation value. Although more than 75<br />
% is relatively undisturbed there are areas of severe<br />
localised disturbance. Weed invasion is one of the most<br />
serious threats with 85 species recorded (Keighery and<br />
Keighery 1995, Brown and Brooks unpubl.).
The most serious threats to plant communities across<br />
the wetlands are South African geophytes. Harlequin<br />
Flower (Sparaxis bulbifera) in particular is present on<br />
the edges of the claypans, throughout the wet flats and<br />
up into the Marri woodlands. It produces vast amounts<br />
of viable seed that germinate each year. Other South<br />
African geophytes that threaten the wetland flora<br />
include Watsonia species, One Leaf Cape Tulip (Moraea<br />
flaccida), Babiana (Babiana angustifolia), Wavy Gladiolus<br />
(Gladiolus undulatus) and Freesia. The South African<br />
grass Tribolium uniolae is a relatively recent invader but<br />
frequent fire in wetlands appears to be facilitating its<br />
movement into otherwise undisturbed areas. Annual<br />
weeds are prolific around the disturbed edges. The<br />
annual sedge Isolepis hystrix is a particularly serious<br />
weed forming dense mats in low-lying wetter areas.<br />
Most of the on-ground management at Brixton Street is<br />
carried out by the Friends of Brixton Street Wetlands; a<br />
community group formed to save the wetlands from<br />
housing development in the early 1990s. The land is still<br />
vested in the state housing authority, Homeswest, and<br />
has been due to transfer to the Department of<br />
Conservation and Land Management (DCLM) for the last<br />
nine years. Management guidelines for the wetlands<br />
have been produced by the Wildflower Society of<br />
Western Australia (Inc.) with financial assistance from a<br />
Community Conservation grant (Keighery and Keighery<br />
1995). DCLM plays some role in management as the area<br />
supports rare flora and threatened plant communities. A<br />
management group with representatives from the<br />
Friends, the Wildflower Society, DCLM, and the City of<br />
Gosnells meets on an irregular basis.<br />
Funding for weed management and bush regeneration<br />
work in recent years has come from the Perth Branch of<br />
the Wildflower Society, DCLM and the City of Gosnells.<br />
Elizabeth Buters, Friends of Brixton Street Wetlands.<br />
Talbot Road <strong>Bushland</strong><br />
Talbot Road <strong>Bushland</strong>, a 95 hectare remnant, lies at the<br />
foot of Darling Scarp on the soils of the Ridgehill Shelf.<br />
Marri, Jarrah and Wandoo (Eucalyptus wandoo)<br />
woodlands occur on the heavier soils and Banksia<br />
woodlands and shrublands on the sandier soils. The<br />
woodlands support an exceedingly diverse understorey<br />
of shrubs, herbs and sedges. Around 366 taxa, many of<br />
Chapter 1 The Project<br />
them rare or restricted, occur across the bushland. It is<br />
the most significant area of Ridgehill Shelf vegetation<br />
remaining and the floristic communities are considered<br />
critically endangered (Keighery and Keighery 1993,<br />
Government of Western Australia 2000). Around 90 % of<br />
the bushland is in good to excellent condition but there<br />
are areas of severe localised disturbance - around drains,<br />
paths and a gravel pit. Around 55 species of weeds occur<br />
in the bushland (Brown and Brooks unpubl.).<br />
The most widespread serious weed in the Talbot Road<br />
<strong>Bushland</strong> is the South African geophyte Hesperantha<br />
falcata. It occurs along path edges throughout the<br />
reserve, moving into undisturbed bushland on the<br />
heavier soils. Other South African geophytes are still<br />
quite localised in their distribution. These include<br />
Freesia, Babiana and Watsonia species. South African<br />
grasses are the other group of serious weeds with<br />
Perennial Veldgrass widespread on the sandier soils<br />
and African Lovegrass (Eragrostis curvula) occurring<br />
across disturbed areas of the bushland.<br />
Talbot Road is vested in the City of Swan and managed<br />
by a committee made up of representatives from the<br />
Friends of Talbot Road, the Department of <strong>Environmental</strong><br />
Protection, DCLM and the City of Swan. Much of the onground<br />
management is carried out by the Friends with<br />
DCLM and the City of Swan playing a significant role. A<br />
Natural Heritage Trust grant to the management group to<br />
implement a management plan (Environs Consulting<br />
1999) has provided consistent funding for weed<br />
management work over the last three years.<br />
Green Corps team hand-removing isolated plants of Perennial<br />
Veldgrass from along paths in Talbot Road <strong>Bushland</strong>.<br />
Gingin Brook<br />
The Gingin Brook, 150 kilometres north of Perth, is fed<br />
by perennial springs arising from the hills north east of<br />
the Gingin townsite. One of the last remaining patches<br />
of fringing vegetation left along the brook where it<br />
crosses the heavier soils at the base of the Dandaragan<br />
Plateau is located in the townsite. For two kilometres<br />
along the brook, Flooded Gum and Swamp Paperbark<br />
(Melaleuca rhaphiophylla) form a dense canopy over an<br />
understorey of native herbs, rushes, sedges and ferns.<br />
The herbs, Centella asiatica, Persicaria salicifolia and<br />
Cotula coronopifolia form ground cover in the wetter<br />
areas while Tassel Sedge (Carex fasciculata), Tall Sedge<br />
(Carex appressa) and the fern, Cyclosorus interruptus,<br />
dominate the understorey.<br />
3
4<br />
Chapter 1 The Project<br />
Both Arum Lily (Zantedeschia aethiopica) and Taro<br />
(Colocasia esculenta) form dense monocultures in<br />
different parts of the fringing vegetation. Two exotic<br />
pasture grasses, Para Grass (Urochloa mutica) and<br />
Reed Sweet Grass (Glyceria maxima) have also become<br />
naturalised, smothering all native vegetation where<br />
they invade. In places woody weeds such as Edible Fig<br />
(Ficus carica) and Brazilian Pepper (Schinus<br />
terebinthifolius) are displacing the native Paperbarks<br />
and Flooded Gums.<br />
The Friends of Gingin Brook, working closely with the<br />
Shire of Gingin, have been responsible for all<br />
restoration works carried out. In 1998 with support<br />
from the shire, they received a grant from the Natural<br />
Heritage Trust to restore the fringing vegetation in the<br />
town site. They have carried out much of the onground<br />
works themselves, sometimes employing<br />
contractors to assist them with weed management.<br />
Green Corps teams have made a major contribution to<br />
the labour force over the life of the project.<br />
Pauline Diggins, Friends of Gingin Brook.<br />
Quairading Nature Reserve<br />
The Quairading Nature Reserve is a 527 hectare crown<br />
reserve, located 164 kilometres east of Perth in the<br />
Western Australian Wheatbelt. The diverse landscape<br />
and soils of the reserve support a range of woodlands<br />
and shrublands. Salmon Gum (Eucalyptus<br />
salmonophloia) and Wandoo woodlands cover the<br />
valley floors, Acorn Banksia (Banksia prionotes) and<br />
Sand Plain Woody Pear (Xylomelum angustifolium)<br />
woodlands cover the deep yellow sands while a series<br />
of shrublands occur on sands and gravel soils<br />
(Keighery et al. 2001). Project work at Quairading was<br />
based in the York Gum (Eucalyptus loxophleba) – Jam<br />
(Acacia acuminata) woodlands that occur on the fertile<br />
brown loams associated with the granites. These<br />
woodlands support a rich annual flora. Through spring<br />
Pink Sunray (Rhodanthe manglesii), Pink Everlasting<br />
(Lawrencella rosea) and Golden Waitzia (Waitzia nitida)<br />
carpet the ground. Later in the season Orange<br />
Immortelle (Waitzia acuminata var. acuminata) and<br />
flowering perennial grasses such as Aristida contorta<br />
and Austrostipa species are noticeable. Shrubs are<br />
uncommon in the understorey.<br />
The vegetation across the reserve is mostly in<br />
excellent condition with only a few serious weeds<br />
present. Around an old settlement, in the Wandoo<br />
woodland, there are a few isolated populations of<br />
Freesia, and One Leaf Cape Tulip is starting to move<br />
down creek lines. In other parts of the reserve a range<br />
of annual weeds occur around old carcass dumps,<br />
rabbit warrens, areas of nutrient run-off from adjoining<br />
farmland and along tracks. Wild Oat (Avena barbata)<br />
and Blowfly Grass (Briza maxima) are the most<br />
widespread weeds across the reserve and can be found<br />
on the more fertile soils of the York Gum – Jam<br />
woodlands, invading the understorey and displacing<br />
the rich annual flora.<br />
The Quairading Shire has had a temporary vesting of<br />
the reserve for the last five years (1998-2002). There is<br />
a reserve management committee with representation<br />
from the Shire, the Quairading District High School, the<br />
Land Care District Committee, Rotary, Rural Youth, the<br />
Golf Club and the Tidy Town Committee. There are few<br />
on-ground resources allocated to weed management or<br />
bushland restoration. The work carried out in the<br />
reserve was in conjunction with local farmers, local<br />
Landcare Coordinators and the District High School. A<br />
workshop was held in the reserve in August 2000<br />
involving EWAN, the Wildflower Society, the local<br />
Quairading community, DCLM and the local shire. The<br />
aim was to foster interest in bushland restoration and<br />
weed management issues.<br />
Participants in a workshop held in the reserve, August 2000.<br />
The work carried out in these bushlands over the last<br />
four years forms the basis for much of the information<br />
and for most of the case studies. The descriptions<br />
highlight how diverse and complex the bushlands<br />
around Perth and south west Western Australia can be.<br />
Managing them for nature conservation means getting<br />
to know individual sites. There are, however, some<br />
universal principles and a general approach that can<br />
underpin effective management of environmental<br />
weeds where they are invading these areas. The<br />
following chapter discusses some of those principles<br />
and provides an outline of the kind of approach that<br />
can be taken when starting out on a bushland<br />
restoration/weed management project. Importantly, the<br />
kind of area-specific information that is vital to<br />
knowing and understanding individual bushlands is<br />
also listed.
Weed management in bushland is concerned with much<br />
more than simply the elimination of weeds. The<br />
underlying objective is always the protection and<br />
restoration of diverse natural ecosystems.<br />
South west Western Australia supports one of the<br />
most diverse floras in the world, occurring in intricate<br />
patterns across a variety of landscapes and soils. For<br />
the southern Swan Coastal Plain alone, 1700 native<br />
taxa (species, subspecies and varieties) have been<br />
recorded occurring in at least 30 different plant<br />
communities (Gibson et al. 1994, Keighery 1999b).<br />
Along a 30 m long and 1 m wide transect through a<br />
population of Harlequin Flower (Sparaxis bulbifera)<br />
invading herblands in the Brixton St Wetlands, up to<br />
28 native taxa and 8 introduced taxa may be found.<br />
<strong>Bushland</strong> weed management in the region is often<br />
about working in complex natural systems with a long<br />
history of varying disturbances. There is a need to<br />
recognise that effective weed management among<br />
such diversity begins with knowing and understanding<br />
each site; the distribution of the native plants and the<br />
native plant communities, the patterns of disturbance<br />
and the distribution of weeds. In particular it is<br />
important to recognise the locally serious weeds. Only<br />
then can weed control and management be strategic –<br />
carefully targeted, and tailored to site conditions and<br />
available resources.<br />
Gathering area-specific information<br />
Note: The information listed below is often compiled when bushland<br />
areas are being identified for retention or as part of a management<br />
plan. When such information is not available it should be compiled as<br />
part of the management program.<br />
Vegetation maps<br />
Vegetation maps of particular bushland areas provide<br />
information on the structure and patterns of native<br />
flora across different landscapes and soils (see<br />
vegetation map of Quairading Nature Reserve, Box 3.2).<br />
When carrying out bushland restoration, vegetation<br />
maps, accompanied by a flora list, provide a vital<br />
reference and an important guide to where in the<br />
landscape particular native species occur and the soils<br />
on which they generally grow.<br />
Flora list<br />
Chapter 2 Managing <strong>Weeds</strong><br />
in <strong>Bushland</strong><br />
Some General Principles<br />
A flora list aims to record all taxa known to occur at a<br />
particular site. A comprehensive flora list is a vital<br />
reference for ensuring species not known to occur<br />
naturally at a particular site are never introduced as a<br />
part of bushland restoration – either through planting<br />
or direct seeding.<br />
In addition, flora lists will often indicate the plant<br />
communities and associated soils and landforms where<br />
particular species can be found growing. At Brixton<br />
Street Wetlands for example, such a flora list provided a<br />
guide for appropriate selection of species for direct<br />
seeding trials located along a degraded edge of herbrich<br />
shrublands on damp, heavy clay soils (see direct<br />
seeding case study 5.1). Flora lists should also include<br />
weeds – it is important to know all flora and to be able<br />
to recognise new weeds as soon as they arrive at a site.<br />
Lists will change over time. When our work began at<br />
Shenton <strong>Bushland</strong> 40 species of weeds were recorded.<br />
After three years of working and getting to know the<br />
site, 25 additional weed species had been identified.<br />
Vegetation condition maps<br />
Impacts of disturbances across a bushland can be<br />
recorded in vegetation condition maps. Fire intensity<br />
and frequency, weed invasion, soil disturbance, disease,<br />
rubbish dumping and past vegetation clearances<br />
interact to impact on the species composition, cover<br />
and structure of native vegetation. Vegetation condition<br />
maps aim to reflect the degree of those impacts.<br />
Combined with maps of the distribution of individual<br />
weed species, they are useful tools for carefully<br />
targeting weed control work to protect relatively<br />
undisturbed bushland (Box 2.1). Mapping of vegetation<br />
condition requires knowledge of native flora as well as<br />
familiarity and understanding of the nature of a<br />
particular undisturbed plant community (see Box 7.1 for<br />
details on criteria used to map vegetation condition).<br />
Weed maps<br />
Maps that provide a clear understanding of where the<br />
serious weeds occur across a bushland site are basic<br />
planning tools. They allow for careful targeting of<br />
limited resources and provide the information required<br />
for strategic weed management. They can provide<br />
useful information on the spread of weed populations<br />
over time and also provide basic information on the<br />
effectiveness of control programs. Not all the weeds in<br />
the bushland need to be mapped – only those that have<br />
a serious impact. See Chapter 7 for how to create and<br />
use weed maps and for some of the criteria that can be<br />
used to determine the serious weeds at a particular<br />
site.<br />
Fauna information<br />
Information on the area’s fauna is also useful.<br />
Sometimes weeds can provide habitat or an<br />
opportunistic food source for native animals. A list of<br />
the known fauna in a bushland can help determine this<br />
at a particular site. Gradual removal of such weeds over<br />
time may be required while animals find alternative<br />
habitat or food sources. For example, dense stands of<br />
Watsonia can provide important habitat for Bandicoots<br />
in the Perth area.<br />
5
6<br />
Chapter 2 Managing <strong>Weeds</strong> in <strong>Bushland</strong><br />
Regional information<br />
Australia is divided up into a series of natural regions.<br />
The Swan Coastal Plain and the Wheatbelt are two<br />
such regions within Western Australia from where case<br />
studies in the text have been drawn. An understanding<br />
of a bushland’s natural values in relation to others in<br />
the region provides information on the area’s<br />
significance. For example, a bushland may be<br />
representative of the more common or rare plant<br />
communities in the region. It is important to note that<br />
the rarest communities (Threatened Ecological<br />
Communities) and flora (Declared Rare Flora – DRF),<br />
are protected by laws, either at the state (DRF) or the<br />
federal (communities) level. Bush Forever, Volume 2 –<br />
Directory of Bush Forever Sites (Government of<br />
Western Australia 2000) catalogues information on<br />
regionally significant bushland on the Swan Coastal<br />
Plain. It provides details on the area of the bushland<br />
type that remains uncleared in the region, how much is<br />
in conservation reserves, the quality and condition of<br />
those bushlands, and where similar bushland can be<br />
found. This type of information is important in<br />
providing a focus for weed management work, and in<br />
gaining an understanding of bushland values that<br />
require protection (Keighery et al. 1998).<br />
Note: <strong>Bushland</strong> restoration carried out where rare flora occurs<br />
requires a permit from the Department of Conservation and Land<br />
Management (DCLM).<br />
Developing a weed<br />
management program<br />
Resources for bushland restoration work are generally<br />
limited. It is critical that these resources are carefully<br />
targeted through strategies that prioritise management<br />
actions, based on a knowledge of the bushland area<br />
and the weeds that are impacting on it. Central to<br />
these strategies are a series of principles that are<br />
fundamental to successful weed management. Many of<br />
the case studies throughout this manual demonstrate<br />
the application of these principles:<br />
• Contain the spread of serious weeds and protect<br />
intact bushland. Consider the impacts of serious<br />
weeds on rare flora and rare plant communities.<br />
• Prevent new weed species establishing.<br />
• Consider restoration of degraded edges. Usually<br />
this is of lower priority than protection of good<br />
areas. Often though, degraded edges harbour<br />
serious weeds, providing a source of propagules<br />
that continually disperse into intact areas.<br />
Implementation – taking an<br />
integrated approach<br />
Prevent new weeds from establishing<br />
• Clean tools, boots, equipment and machinery<br />
between jobs to reduce risk of spread<br />
between sites.<br />
• Practise soil hygiene.<br />
• Check paving materials before bringing on to a<br />
site, particularly limestone, for weed seed and<br />
only acquire from accredited clean sources. Black<br />
Flag (Ferraria crispa), Geraldton Carnation Weed<br />
(Euphorbia terracina) and Pretty Betsy<br />
(Centranthus rubra) to name a few have been<br />
introduced to various bushland sites around Perth<br />
in paving materials.<br />
• Avoid bringing soil or mulch from elsewhere into<br />
bushland.<br />
• Know the plants of your bushland (native and<br />
introduced) and immediately remove infestations<br />
of any new weeds. This is important at individual<br />
sites but also at a regional and state level.<br />
See case study 5.2 on Holly-leafed Senecio<br />
(Senecio glastifolius) a recent invader to south west<br />
Western Australia.<br />
Limit the spread of established weeds<br />
• Target small populations in good bush and the<br />
outliers of dense infestations - use the maps<br />
(Box 2.1).<br />
• Keep soil disturbance to a minimum. Disturbance<br />
favours the establishment of many weeds. It brings<br />
buried weed seed to the surface thereby releasing<br />
dormancy, and creates favourable conditions for<br />
the germination of wind dispersed weed seed.<br />
• Avoid working in areas where weeds are actively<br />
shedding seed.<br />
• Post-fire conditions (space, light and high nutrient<br />
availability) often favour establishment of weeds.<br />
Weed control in the season immediately following<br />
fire will prevent seed set in established weeds and<br />
reduce germinating weed seedlings. It will limit the<br />
inevitable spread of many serious bushland weeds<br />
through the post-fire landscape.<br />
See Box 4.2 on fire and cormous and bulbous weeds,<br />
Box 5.1 on the weeds that move in with soil<br />
disturbance, and Box 3.5 on limiting the spread of<br />
Perennial Veldgrass following fire.
Chapter 2 Managing <strong>Weeds</strong> in <strong>Bushland</strong><br />
Box 2.1 Strategy for the management of Yellow Soldier (Lachenalia reflexa) invading a<br />
Banksia woodland at Shenton <strong>Bushland</strong>.<br />
This strategy is simply an illustration of how some of the information covered in this chapter can be<br />
used to help set priorities and develop an effective works program.<br />
Biology<br />
Yellow Soldier flowers in winter and early spring, dying back to a bulb over summer. It sets prolific amounts of<br />
viable seed (around 40 seed per flower) and up to 1700 bulbs can occur in four square metres. Seed appears to<br />
remain viable in the soil for only a couple of years and may be dispersed by water. Plants are not killed by<br />
summer fire, but flower well and are highly visible in the post-fire landscape. In addition high numbers of<br />
seedlings have been observed establishing on bare ground left following fire.<br />
Suggested Control Methods<br />
For isolated plants in sandy soils use a knife to cut the roots and pull out with bulb in July to early August. Trials<br />
have shown metsulfuron methyl at<br />
2.5-5 g/ha, applied just before<br />
flowering, in late July, provides<br />
effective control with little impact<br />
on co-occurring native species.<br />
Carefully spot spray.<br />
Recommended strategy for the<br />
effective management of Yellow<br />
Soldier and regeneration of the<br />
Banksia woodland it is invading<br />
Hand-removal of entire populations<br />
is time consuming (up to six hours<br />
for four square metres) and soil<br />
disturbance results in germination<br />
of annual weeds. Specifically<br />
targeted herbicide treatment is<br />
recommended for dense<br />
infestations and hand-weeding for<br />
isolated plants.<br />
The populations on the eastern<br />
side of the reserve and at the<br />
southern end of the reserve are<br />
both relatively small, occurring in<br />
very good to excellent condition<br />
bushland and should both be high<br />
priority for eradication.<br />
The larger population of<br />
Yellow Soldier on the western side<br />
of the bushland is spreading<br />
through a more degraded area and<br />
is not as high a priority if resources<br />
are limited.<br />
Following fire, resources should be<br />
allocated for control. At this time<br />
plants are an easy target for<br />
herbicide control and prevention<br />
of flowering and seed set will<br />
limit establishment in the<br />
post-fire landscape.<br />
Allow indigenous species to<br />
recolonise the treated sites<br />
unassisted (Yellow Soldier<br />
co-occurs with up to 25 native<br />
Figure 1. The distribution of Yellow Soldier • and vegetation condition across<br />
Shenton <strong>Bushland</strong>.<br />
<strong>Bushland</strong> condition<br />
species in a 2 m x 2 m plot). very good - excellent fair - good poor very poor<br />
7
8<br />
Chapter 2 Managing <strong>Weeds</strong> in <strong>Bushland</strong><br />
Understand the biology of a particular weed<br />
species – focus on how the weed reproduces<br />
and spreads<br />
• When is it actively growing?<br />
• When is it flowering and seeding?<br />
• How long do seed or other propagules remain<br />
viable in the soil?<br />
• How does it respond to fire?<br />
• What are the vulnerable times in the life-cycle?<br />
• Is there a preferred time for physical control?<br />
• What is the preferred time for chemical control?<br />
See case study 3.2 on learning about the biology of<br />
Tribolium, case study 3.4 on timing Perennial Veldgrass<br />
control, Box 4.4 on corm exhaustion and herbicide<br />
application and case study 6.2 on timing Fig removal.<br />
Consider all the control options<br />
• Consider the impact of control options on<br />
co-occurring native flora including trees, shrubs,<br />
geophytes, grasses, and other native herbs and<br />
on fauna.<br />
• Physical, chemical and biological methods are all<br />
useful in managing bushland weeds.<br />
• A combination of techniques is required for<br />
practical and effective long-term outcomes.<br />
• It is important to adapt control methods to<br />
site-specific conditions and available resources.<br />
See case studies 4.4 on methods used to control<br />
Harlequin Flower (Sparaxis bulbifera) and 4.3 on<br />
control of Taro (Colocasia esculenta).<br />
Assist natural regeneration<br />
• Assist natural regeneration through carefully<br />
targeted weed removal.<br />
• Stimulate germination of the native soil seedbank<br />
with smoke products or, where the native<br />
seedbank is depleted, consider direct seeding.<br />
Always use locally collected seed.<br />
• Management practice that favours the<br />
regeneration of native plants increases<br />
competition against weeds.<br />
See case study 5.1 on direct seeding and Box 5.3 on<br />
assisting natural regeneration.<br />
Keep a record of works programs over time<br />
Keeping a record of works programs over time is an<br />
important component of bushland restoration. A<br />
logbook should record date, time and type of works<br />
carried out including details of methods used, hours<br />
worked, and site conditions.<br />
Monitor the outcomes of weed<br />
management work<br />
Detailed monitoring of weed populations provides a<br />
quantitative record of the effectiveness of<br />
management programs, measures the impact of the<br />
control programs on native plants and the<br />
regeneration of the native plant community over time.<br />
The feedback provided can be used to adapt future<br />
management practices and to justify spending on<br />
weed management works.<br />
How you monitor will depend on the changes to be<br />
detected, the scale and distribution of the infestation,<br />
and the nature of the vegetation the weed/s are<br />
invading. Setting up monitoring that is useful for<br />
detecting detailed change over time is necessarily<br />
complex. For a particularly useful reference see<br />
‘Monitoring Plant and Animal Populations’ by Elzinga et<br />
al. (2001). ‘The Standard Operating Procedure for<br />
Monitoring Weed Control’ by the Department of<br />
Conservation, New Zealand (2000) is also a particularly<br />
useful reference and is designed to provide a detailed<br />
working framework for field officers.<br />
Case studies in the tuberous, bulbous and cormous<br />
weeds chapter and the grass weeds chapter illustrate<br />
some of the methods used over the life of our project<br />
to measure the effectiveness of weed management<br />
work, impacts on associated native plants and in some<br />
cases, regeneration of the native plant community.<br />
See case studies 3.4 in the grass chapter and 4.1, 4.2,<br />
and 4.3 in the bulbs chapter.<br />
The following chapters illustrate how the information<br />
outlined here underpins effective weed management in<br />
bushland and is vital in providing a framework for the<br />
protection of unique bushland values. The management<br />
of grass weeds is covered first, in the next chapter.
The grass weeds as a group, particularly the South<br />
African perennial species, are a serious threat to<br />
bushland around Perth. This chapter looks at grass<br />
biology and the factors contributing to the invasion and<br />
establishment of weed grasses, in particular fire and<br />
canopy degradation. The influence of lifeform and<br />
growth form on management decisions is highlighted<br />
and the importance of growth stage on timing of<br />
control programs discussed. Finally, a table with<br />
information on the biology of individual species and<br />
available control measures is presented.<br />
In terms of number of individuals, biomass, area<br />
covered and diversity of habitat, grasses are one of the<br />
most successful plant families in the world (Gibbs<br />
Russell et al. 1991, D’Antonio et al. 2000). The<br />
characteristics that have contributed to this success<br />
have also enabled many grasses to become aggressive<br />
invaders of natural ecosystems.<br />
Almost one third of the 709 grass species recorded in<br />
Western Australia are exotic (Western Australian<br />
Herbarium 1998). In south west Western Australia,<br />
331perennial grasses were introduced and screened as<br />
potential pasture species between 1943 and 1970 (Rogers<br />
et al. 1979). Of these, 14 % are now naturalised in<br />
Western Australia (Western Australian Herbarium 1998)<br />
and many are now considered weeds of bushland of the<br />
Swan Coastal Plain and Jarrah Forest (Keighery 1999a).<br />
These include serious invasive grasses such as African<br />
Lovegrass (Eragrostis curvula), Perennial Veldgrass<br />
(Ehrharta calycina), Tambookie Grass (Hyparrhenia<br />
hirta), Kikuyu (Pennisetum clandestinum), Fountain Grass<br />
Box 3.1 Native grasses of the Perth Region<br />
Chapter 3 Grass <strong>Weeds</strong><br />
(Pennisetum setaceum) and the coastal invaders,<br />
Marram Grass (Ammophila arenaria) and Pyp Grass<br />
(Ehrharta villosa). Horticulture has also been<br />
responsible for the introduction of a number of serious<br />
grass weeds, among them Pampas Grass (Cortaderia<br />
selloana) which is still seen in Perth gardens. However,<br />
it is important to identify unknown grass species and<br />
not just assume that because it is a grass it is a weed<br />
(Box 3.1).<br />
Impacts<br />
Introduced grasses are competitive in many native<br />
ecosystems; they may displace the native understorey<br />
and alter fire regimes (Humphries et al. 1991). The<br />
impact a particular grass species has is partly<br />
determined by the characteristics of the invaded site<br />
(Box 3.2). In south western Australia the annual<br />
grasses, Wild Oat (Avena barbata) and Blowfly Grass<br />
(Briza maxima), threaten the herbaceous flora found<br />
on the granitic soils of Wheatbelt reserves. Perennial<br />
Veldgrass is highly invasive in the sandy, nutrient-poor<br />
soils of the Swan Coastal Plain - soils commonly<br />
occupied by Banksia woodland. Kikuyu, Water Couch<br />
(Paspalum distichum) and Vasey Grass (Paspalum<br />
urvillei) invade the more nutrient-rich wetlands and<br />
Tambookie Grass tends to occur on the heavier soils<br />
of the Darling Scarp. Grasses often colonise disturbed<br />
edges or patches within bushland. This edge<br />
colonisation allows the grass to take advantage of any<br />
disturbance event within the bushland, establishing<br />
rapidly after fire, clearing or soil disturbances.<br />
Of the numerous native grasses occurring in Perth’s bushland, many are mistaken for weeds. Knotted Poa (Poa<br />
drummondiana) is superficially similar to Winter Grass (Poa annua), while Kangaroo Grass (Themeda triandra)<br />
is often mistaken for Tambookie Grass. Some native grasses simply look ‘weedy’ to the untrained eye, including<br />
Swamp Wallaby Grass (Amphibromus nervosus), Clustered Lovegrass (Eragrostis elongata) and Marine Couch<br />
(Sporobolus virginicus).<br />
Native grasses that occur in the Perth region include:<br />
*Bold indicates that weedy species from the same genus that can be found in the Perth area.<br />
Agropyron scabrum Austrodanthonia occidentalis Dichelachne crinita<br />
Agrostis avenacea Austrodanthonia pilosa Eragrostis elongata<br />
Agrostis plebeia Austrodanthonia racemosa Glyceria australis<br />
Agrostis preissii Austrodanthonia setacea Hemarthria uncinata<br />
Amphibromus nervosus Austrostipa campylachne Microlaena stipoides<br />
Amphibromus vickeryae Austrostipa compressa Neurachne alopecuroidea<br />
Amphipogon avenaceus Austrostipa elatior Neurachne minor<br />
Amphipogon amphipogonoides Austrostipa elegantissima Poa drummondiana<br />
Amphipogon debilis Austrostipa flavescens Poa poiformis<br />
Amphipogon laguroides Austrostipa macalpinei Poa porphyroclados<br />
Amphipogon strictus var. hirsutus Austrostipa pycnostachya Polypogon tenellus<br />
Amphipogon strictus var. setifera Austrostipa semibarbata Spinifex hirsutus<br />
Amphipogon turbinatus Austrostipa tenuifolia Spinifex longifolius<br />
Aristida contorta Austrostipa variabilis Sporobolus virginicus<br />
Aristida ramosa Bromus arenarius Tetrarrhena laevis<br />
Austrodanthonia acerosa Deyeuxia quadriseta Themeda triandra<br />
Austrodanthonia caespitosa<br />
List from Keighery (1999b)<br />
9
10<br />
Chapter 3 Grass <strong>Weeds</strong><br />
Many grasses use the disturbance caused by bushfire<br />
to get a foothold within bushland areas. In turn, grass<br />
invasions increase fuel loads which indirectly impact on<br />
the native ecosystem by changing fire frequency,<br />
intensity, patchiness, size and timing (Humphries et al.<br />
1991, Mack and D’Antonio 1998). The introduction of<br />
Buffel Grass (Cenchrus ciliaris) as a pasture species<br />
throughout arid and semi-arid regions of Australia is<br />
said to have drastically altered the fire regime. In areas<br />
where the grass occurs, fuel loads are high and<br />
continuous. Dry water courses which previously acted<br />
as fire breaks are now bridged by fire and also act as<br />
wicks, spreading the fire further (Humphries et al.<br />
1991). More locally, Perennial Veldgrass, Lovegrass and<br />
Fountain Grass are all fire adapted, resprouting<br />
vigorously and seeding prolifically after bushfires<br />
(Christensen and Abbott 1989, Walsh 1994, Milberg and<br />
Lamont 1995, Benton 1997, Muyt 2001). Changes in the<br />
fire regime can have long term impacts on the structure<br />
and composition of the native communities (Williams<br />
and Baruch 2000). Indeed, the change in fire regime<br />
brought about by Buffel Grass invasion has converted<br />
areas of the Sonoran Desert cactus forests of Central<br />
America into grassland (Van Devender et al. 1997).<br />
Box 3.2 Ecosystem susceptibility: Resource availability, soil structure and Wild Oat<br />
In the Wheatbelt of Western Australia Wild Oat (Avena barbata) is often associated with York Gum<br />
(Eucalyptus loxophleba) – Jam (Acacia acuminata) woodlands. The soils of these woodlands are characterised<br />
by high values of nitrogen, phosphorus and potassium. They are friable and lack a hard crust, making them<br />
more susceptible to weed invasion (Hobbs and Atkins 1988, Arnold et al. 1998). The distribution of Wild Oat<br />
and Blowfly Grass (Briza maxima) at Quairading Nature Reserve illustrates the association between the<br />
woodlands and the two annual grass weeds (Figure 1).<br />
The almost exclusive absence of Wild Oat and Blowfly<br />
Grass from other plant communities in the reserve<br />
may be attributed to a range of factors, poor nutrient<br />
levels among them.<br />
Heath and Tamar (Allocasuarina species)<br />
communities form dense thickets, competing strongly<br />
for resources and preventing the majority of light<br />
from penetrating the low canopy.<br />
Salmon Gum (Eucalyptus salmonophloia) woodlands<br />
have an open understorey with large areas of bare<br />
ground and only dappled shade. However, even on the<br />
reserve edges, there is very little weed incursion. The<br />
soils associated with these woodlands form a hard<br />
crust, relatively impervious to seeds not adapted to<br />
self-burial. Salmon Gums also have an extensive lateral<br />
root system near the soil surface competing strongly<br />
for available surface moisture and inhibiting<br />
establishment of grass weed species (Yates et al. 2000).<br />
Wandoo (Eucalyptus wandoo) woodlands are slightly<br />
more prone to invasion. Like Salmon Gums, Wandoo<br />
woodlands have a relatively open canopy, but the soil<br />
crust appears less impervious. Where Wandoo blends<br />
into Jam, patchy Wild Oat distribution often occurs.<br />
Where Wild Oat occurs within other plant<br />
communities it is associated with reserve edges or<br />
disturbance from rabbits or machinery. The only<br />
exception to this is two small patches growing under<br />
the Christmas Tree (Nuytsia floribunda). This parasitic<br />
plant may increase nitrogen within the soil by<br />
accumulating the element from host plants. The<br />
nitrogen is then released into the surrounding soil<br />
when flowers and leaves are shed (Hocking 1980).<br />
Understanding the relationship between vegetation<br />
communities and weed invasions is important to<br />
management. Susceptible areas can be targeted for<br />
weed prevention and early control. Vegetation maps<br />
can be used as a rough guide to possible weed<br />
distribution at other sites, enabling the estimation of<br />
resources required for control.<br />
Salmon Gum Woodland<br />
Wandoo Woodland<br />
Wandoo Woodland on laterite<br />
York Gum - Jam Woodland<br />
Degraded York Gum Woodland<br />
York Gum - Jam - Rock Sheoak Woodland<br />
Granite outcrop<br />
Lithic Complex<br />
Tamar Woodland on sandy gravels<br />
Tamar Shrubland on lateritic gravel<br />
Tamar Shrubland on sandy clay<br />
Heaths on deep grey sand<br />
Tamar - Dryandra - Eremaea Shrubland on cream sand<br />
Tamar - Eucalyptus macrocarpa Shrubland on yellow sand<br />
Banksia prionotes - Sand Plain Woody Pear Low Woodland<br />
Cleared<br />
Patchy Wild Oat and Blowfly Grass cover<br />
Dense Wild Oat and Blowfly Grass cover<br />
Figure 1. Vegetation complexes occurring within Quairading Nature<br />
Reserve, and the distribution and density of Wild Oat and Blowfly<br />
Grass across the reserve.<br />
(Vegetation map adapted from Keighery et al. 2001)
Fire is less important in the establishment of weedy<br />
grasses in wetlands and riparian zones. Instead,<br />
invasion of weed grasses is often encouraged by poor<br />
land management practices that increase nutrient runoff<br />
into streams and wetlands. The disturbance caused<br />
by grazing along waterways can also promote the<br />
spread of weed grasses. The grasses that commonly<br />
invade wetlands are often rhizomatous, their rapid<br />
growth and mat-forming habit smothering native plants<br />
and preventing further recruitment. Some semi-aquatic<br />
grasses, such as Johnson Grass (Sorghum halepense),<br />
Reed Sweet Grass (Glyceria maxima) and Para Grass<br />
(Urochloa mutica) grow in up to one metre of water.<br />
These species can form large floating mats that reduce<br />
the habitat of waterfowl, slow and change the direction<br />
of water flow, alter silt deposition displace food sources<br />
and reduce nesting sites (Humphries et al. 1991).<br />
Biology – why are grasses<br />
successful weeds?<br />
The structural design of grasses helps make them<br />
highly competitive. The presence of axillary buds at<br />
the base of each internode allows most grasses to<br />
resprout vigorously when damaged (Gibbs Russell et<br />
al. 1991). This advantage is compounded by the<br />
development of crown tissue at the base of the grass<br />
plant. Crown tissue produces buds at or below ground<br />
level where they are largely protected from the<br />
environment. These buds are the source of rhizomes,<br />
stolons (Box 3.3) and tillers (new grass shoots or<br />
culms arising at or near the base of the primary culm).<br />
Soon after a seedling germinates, adventitious roots<br />
develop from the crown tissue, firmly anchoring the<br />
plant to the ground. These roots<br />
store excess carbohydrates and<br />
can permeate large volumes of<br />
soil very efficiently, making<br />
grasses highly competitive<br />
for moisture and nutrients<br />
(Hannaway et al. 2000, Gibbs<br />
Russell et al. 1991). Grasses<br />
are broadly grouped into<br />
two lifeform categories,<br />
annuals and perennials:<br />
Annual grasses complete<br />
their life-cycle in a single<br />
growing season, storing all<br />
their excess photosynthate<br />
(plant food) within the seed<br />
(Hannaway et al. 2000).<br />
Annual grasses like Wild<br />
Oat, Blowfly Grass,<br />
Annual Veldgrass<br />
(Ehrharta longiflora),<br />
Silvery Hairgrass<br />
(Aira caryophyllea)<br />
and Barnyard Grass<br />
(Echinochloa crus-galli) all<br />
adventitious roots<br />
inflorescence<br />
axillary buds<br />
or nodes<br />
internode<br />
tiller buds location of<br />
crown tissue<br />
Chapter 3 Grass <strong>Weeds</strong><br />
rely entirely on seedling recruitment to establish<br />
within an area. Annual grasses are usually tussock<br />
forming or caespitose (Box 3.3), although occasionally<br />
tillers of prostrate grasses may root at the nodes.<br />
Perennial grasses reproduce vegetatively as well as by<br />
seed, storing excess photosynthate within rhizomes,<br />
stolons, seed and occasionally corms (swollen<br />
underground stem bases). Perennials develop winteror<br />
summer- hardy buds capable of resuming growth<br />
the following season (Hannaway et al. 2000). Perennials<br />
can be sterile and still reproduce vigorously, spreading<br />
by stolon, rhizome and dispersal of grass root<br />
fragments in water and soil, Kikuyu and Giant Reed<br />
(Arundo donax) being just two examples. Perennial<br />
grasses generally fall into one of three descriptive<br />
growth forms, caespitose or tussock-forming,<br />
rhizomatous and stoloniferous (Box 3.3).<br />
Reproduction, dispersal and persistence –<br />
implications for limiting spread<br />
Sexual reproduction<br />
Seed is important for the spread and establishment of<br />
many perennial grasses. For the annual lifeform,<br />
seedling recruitment is essential.<br />
Dispersal: An understanding of seed dispersal<br />
mechanisms allows us to limit further spread and reinfestation,<br />
an important, although often overlooked,<br />
component of any management program.<br />
• Wind plays a central role in dispersal and many<br />
grasses occupy open habitats subject to frequent<br />
winds. Small, lightweight seed, suitable for wind<br />
dispersal, is the most common form found in the<br />
grasses. To further aid wind dispersal the outer<br />
bracts may be covered with long soft hairs<br />
(Davidse 1986). Seed from adjacent degraded areas<br />
can be carried into the bushland by prevailing<br />
winds, providing seed rain after a disturbance<br />
event such as fire. Depending on the species this<br />
deposited seed may establish as a seedbank, ready<br />
to germinate given the appropriate conditions.<br />
Once ripe, wind dispersed seed is easily<br />
dislodged and careless removal of grass weeds<br />
at this stage will facilitate dispersal.<br />
Preferably, seed heads should be removed and<br />
bagged prior to this stage.<br />
• Water can disperse large numbers of seeds. The<br />
light weight of many seeds allows them to float<br />
easily. Seeds may have aerenchymous tissue, the<br />
tiny air pockets aiding flotation. Some seeds have<br />
a long awn that helps embed the seed when it<br />
reaches a suitable embankment (Davidse 1986).<br />
Run-off from rainstorms can carry grass seed<br />
downhill and into creeks and storm drains,<br />
concentrating vast numbers of seeds in the<br />
wetlands they feed into.<br />
Upstream and uphill source populations need<br />
to be managed. Drain outlets can have<br />
sumps incorporated to allow weed seed to<br />
settle and collect.<br />
11
12<br />
Chapter 3 Grass <strong>Weeds</strong><br />
Box 3.3 Grass growth forms<br />
Caespitose or tussock grasses are the dominant<br />
grass growth form around the world. Examples<br />
include the bushland weeds Perennial Veldgrass<br />
(Ehrharta calycina), Pampas Grass (Cortaderia<br />
selloana), Tambookie Grass (Hyparrhenia hirta) and<br />
Lovegrass (Eragrostis curvula). Reproducing by seed<br />
and/or tillers they form dense, usually erect, clumps.<br />
As clumps age, each year’s old leaf material<br />
accumulates, creating large fuel loads (Briske and<br />
Derner 1998, Hannaway et al. 2000). Caespitose<br />
grasses typically occupy resource-poor habitats. By<br />
accumulating soil organic carbon and nitrogen<br />
directly beneath clumps, they monopolise resources<br />
(Gibbs Russell et al. 1991).<br />
African Lovegrass (Eragrostis curvula)<br />
Stoloniferous grasses are creeping or mat-forming<br />
grasses that spread locally by stolons and include<br />
Para Grass (Urochloa mutica) and Queensland Blue<br />
Grass (Digitaria didactyla). A stolon is a segmented,<br />
horizontal stem, which runs predominantly along<br />
the soil surface. Adventitious roots and aerial shoots<br />
arise from stolon nodes. Stolons themselves arise<br />
from adventitious buds in the crown tissue.<br />
Propagation is both vegetative, from stolon<br />
fragments, and from seed. Although commonly<br />
occupying moist, high nutrient areas, some foredune<br />
species such as Spinifex (Spinifex sericeus) and<br />
Saltwater Couch (Paspalum vaginatum) are<br />
stoloniferous. Many stoloniferous grasses are<br />
considered invasive species (Hannaway et al. 2000).<br />
Para Grass (Urochloa mutica)<br />
Rhizomatous grasses form dense mats, extending<br />
their coverage by producing below-ground lateral<br />
rhizomes. A rhizome is a modified underground stem<br />
capable of rooting and shooting at nodes to develop<br />
daughter plants. They can serve as storage tissue<br />
for vegetative propagation and, being underground,<br />
are protected from fire. These grasses, including<br />
species like Reed Sweet Grass (Glyceria maxima),<br />
Pyp Grass (Ehrharta villosa) and Johnson Grass<br />
(Sorghum halepense), propagate vegetatively, but<br />
may also spread by seed. Rhizomatous grasses<br />
dominate moister, more nutrient-rich habitats and<br />
are often invasive (Hannaway et al. 2000).<br />
Many grasses can be both rhizomatous and<br />
stoloniferous, Couch (Cynodon dactylon) and Kikuyu<br />
(Pennisetum clandestinum) being just two examples.<br />
Reed Sweet Grass (Glyceria maxima)<br />
rhizome<br />
node<br />
adventitious shoot<br />
node<br />
stolon<br />
tiller buds<br />
adventitious shoot<br />
adventitious root
• Animals can carry grass seeds on their skin and<br />
fur. Seed bracts and/or awns may have sticky<br />
hairs, hooks or spines that aid adhesion. Ingestion<br />
also plays a role in grass dispersal. Grasses<br />
evolved with grazing and several authors have<br />
noted seeds are voided intact (Davidse 1986).<br />
Dogs, horses, native animals and humans<br />
(among others) readily disperse seeds along<br />
bush tracks. Horses can spread grass weeds<br />
from paddocks into bushland, depositing seed<br />
with their manure.<br />
• Human activities including inappropriate<br />
management practices, provide additional<br />
mechanisms for grass weed dispersal:<br />
Grading drags seed (and tillers) along road verges.<br />
Slashing during flowering spreads seed with an<br />
explosive action.<br />
Lawn clippings dumped in bushland often<br />
contain grass seed.<br />
Soil seedbanks: Seedbanks consist of dormant seed,<br />
which is ready to germinate given the appropriate<br />
environmental cues. Dormancy allows seed to persist<br />
in the soil in the absence of further seed rain.<br />
As a general rule grass seeds are not considered to be<br />
persistent within the soil. However, there are<br />
exceptions. Numerous grasses have a soil seed life<br />
greater than five years and not surprisingly many of<br />
these are widespread weeds (eg. Fountain Grass and<br />
Barnyard Grass). Poa pratensis and a number of<br />
Setaria species are known to remain viable for at least<br />
39 years (Baskin and Baskin 1998). <strong>Environmental</strong><br />
factors, including temperature, moisture and light<br />
intensity can induce dormancy in seeds. For example,<br />
deep burial induces dormancy in Wild Oat seed,<br />
increasing its longevity from six months to anything up<br />
to ten years (Baskin and Baskin 1998, Nugent et al.<br />
1999). Dormancy is broken when the seed is returned<br />
to the surface through soil disturbance.<br />
For many species, seed longevity is not understood<br />
and yet it is invaluable information when making<br />
management decisions. The length of a control<br />
program is largely determined by seedbank<br />
persistence. The shorter lived the seed, the more<br />
rapidly a grass infestation can be controlled<br />
(provided the source is no longer<br />
present or is also managed).<br />
Chapter 3 Grass <strong>Weeds</strong><br />
Vegetative reproduction<br />
Vegetative reproduction as a strategy in grasses is<br />
most successful in moist, nutrient-rich conditions<br />
(Briske and Derner 1998). Under these conditions<br />
rhizomatous and stoloniferous grasses can easily<br />
establish roots and rapidly disperse rhizome and<br />
stolon fragments in soil and down streams. In Reed<br />
Sweet Grass (and possibly other species), shoots of<br />
young plants can be vegetative or flowering. However,<br />
once established, the majority of new shoots produced<br />
are vegetative. This strategy allows the plant to quickly<br />
colonise new areas by seed, whilst increasing the<br />
density of established plants (Department of Primary<br />
Industries Water and Environment 2001).<br />
Tussock-forming grasses may also propagate<br />
vegetatively. Tillering is responsible for each season’s<br />
new growth and the expansion in tussock area<br />
(Hannaway et al. 2000). Tillers are also referred to as<br />
sprouts, shoots and daughters and may break off when<br />
disturbed.<br />
If resources are scarce, management should focus<br />
on controlling the invading edge(s) and new or<br />
isolated populations.<br />
Grass growth stages<br />
As with all weeds the timing of grass control measures<br />
is important. Active growth is required for herbicide<br />
uptake and slashing can enhance leafy growth or result<br />
in defoliation, depending on the growth stage. In most<br />
grasses (sterile grasses are the exception) there are<br />
three main stages of active grass growth: Vegetative,<br />
transition and flowering.<br />
• Vegetative growth involves the production of<br />
shoots, mostly leaf blades but also stolons and<br />
rhizomes. Herbicides are best applied at this stage,<br />
while slashing usually results in increased<br />
production of leafy material.<br />
vegetative transition boot stage<br />
flowering<br />
13
14<br />
Chapter 3 Grass <strong>Weeds</strong><br />
• Transition occurs when the growing points stop<br />
producing vegetative material and start developing<br />
flowers and the tissue between nodes, the<br />
internode, elongates. Because of internode<br />
elongation, slashing or mowing at this stage can<br />
remove many axillary buds, thereby reducing leaf<br />
production in the regrowth.<br />
• Flowering begins when the seed head is just<br />
emerging from the leaf sheath (boot stage) and<br />
continues through to seeding. Some grass-selective<br />
herbicides are only effective if applied prior to the<br />
boot stage. Slashing or mowing during flowering<br />
may facilitate the spread of seed.<br />
The period of active growth depends largely on<br />
whether the plant is a cool season (C3) or warm<br />
season (C4) grass. Cool season and warm season<br />
grasses differ in the way they use carbon dioxide. Cool<br />
season grasses (Wild Oat, Blowfly Grass, Perennial<br />
Veldgrass) photosynthesise more effectively, and thus<br />
are most actively growing, during the cooler periods of<br />
winter and spring (15-25° C). Warm season grasses, or<br />
summer grasses, photosynthesise best with full light<br />
saturation and consequently their period of most<br />
active growth is late spring and summer (25-40° C).<br />
The summer growing Couch (Cynodon dactylon),<br />
Kikuyu and Lovegrass are all C4 grasses.<br />
For successful herbicide uptake grasses should be<br />
sprayed in the season appropriate to their<br />
photosynthetic pathway and when actively growing.<br />
Fire and the spread of grass weeds<br />
Many grasses, especially caespitose species, have long,<br />
narrow, vertical leaves that are efficient in strong light<br />
allowing sunlight to penetrate deep inside the clump<br />
(Gibbs Russell et al. 1991). This structure allows the<br />
production of a large biomass in a small space. Stems<br />
die each year and new ones develop. Over time a large<br />
biomass, much of it dead material, creates a significant<br />
fire hazard. As a result, grass weed invasions can lead<br />
to changes in fire frequency and intensity.<br />
These changes are self-perpetuating as the disturbance<br />
caused by fire tends to promote germination and<br />
establishment of seedling grasses (Cheplick 1998,<br />
Williams and Baruch 2000). At Shenton <strong>Bushland</strong>,<br />
Perth, Perennial Veldgrass was mapped in the year<br />
following an intense fire that burnt half of the site. A<br />
comparison between a pre-fire bushland condition map<br />
and the post-fire Veldgrass map, highlighted a<br />
significant post-fire expansion in the population.<br />
Previously healthy bushland now recorded 75-100 %<br />
cover of Veldgrass (Brown and Marshall<br />
unpublished data).<br />
Fire contributes greatly to grass invasion in lownutrient<br />
soils, where post-fire increases in nutrients,<br />
light and space availability are more effectively<br />
exploited by invasive grasses than by the native flora.<br />
It is important to reduce the possibility of fire in<br />
bushland areas at risk of grass invasion. Where<br />
bushfire does occur target resprouting plants and<br />
seedlings for control before they become<br />
established.<br />
Management and control<br />
Prevention and early intervention<br />
Degradation of our native bushland remnants through<br />
clearing, fire, disease and mismanagement may be of<br />
particular relevance to the establishment and spread<br />
of grass weeds. Often an observed decline in the<br />
canopy cover within Banksia woodlands around Perth<br />
correlates with an increase in the occurrence of<br />
Perennial Veldgrass. Reduction in canopy cover leads<br />
to an increase in light availability, a condition favoured<br />
by many grass weeds (Williams and Baruch 2000,<br />
D’Antonio et al. 2001).<br />
Weed grass invasion can be limited by:<br />
• Maintaining the bushland canopy. Many grasses<br />
prefer open sunny sites and do not establish or<br />
compete successfully in the shade.<br />
• Reducing the potential for bushfires. As<br />
mentioned, fire can significantly increase the<br />
establishment and spread of grass weeds.<br />
• Identifying unfamiliar grasses. It is important to<br />
determine if grasses are introduced or native.<br />
Early identification of grass weeds allows you to<br />
assess the likelihood of invasion and prevents<br />
mistaken eradication of native grasses!<br />
• Establishing weed barriers.<br />
Weed barriers<br />
A common grass weed problem in urban remnants is<br />
the spread of Kikuyu, Couch or Buffalo Grass<br />
(Stenotaphrum secundatum) from adjacent parks and<br />
road verges. A successful ‘weed break’ can be created<br />
by embedding a physical barrier such as weed mesh or<br />
conveyor belt vertically into the ground and using<br />
concrete kerbing above it. This prevents rhizomes<br />
creeping into the bushland and provides a mowing<br />
edge for council mowers (Box 3.4). Some grasses have<br />
rhizomes 50 to 60 centimetres below ground and any<br />
root barrier must allow for this.<br />
The bush itself often provides an excellent weed break<br />
(Box 3.2). However, the sandy soils and open<br />
vegetation of Banksia woodland or the friable soils of<br />
York Gum–Jam woodlands are more susceptible.<br />
Establishing a dense cover of locally-occurring low,<br />
medium and tall shrubs along the edges of degraded<br />
sites and paddocks could act as a sieve, preventing<br />
entry of wind and water carried seed. Knowing the<br />
prevailing wind direction, position in the landscape<br />
and relationship to waterflow can help to determine if<br />
the adjacent paddock, weedy rail reserve or over-run,<br />
semi-rural backyard, is the weed source. When planting<br />
or direct seeding, use native seed collected from the<br />
area of bushland you are protecting and only plant<br />
where run-off or prevailing winds are definitely<br />
carrying weed seed in.
Box 3.4 Spread of turf grass at Blue Gum Lake<br />
Chapter 3 Grass <strong>Weeds</strong><br />
At Blue Gum Lake in the City of Melville, parkland often adjoins bushland. In most of these sites Couch<br />
(Cynodon dactylon) and Kikuyu (Pennisetum clandestinum) have been planted as turf. On one boundary<br />
between turf and bushland a large infestation of the woody weed Geraldton Wax (Chamelaucium uncinatum)<br />
was removed. The site revegetation project was undertaken by the Friends of Blue Gum Lake who were continually<br />
faced with Couch that kept creeping back from the grassed area. After spraying the Couch several times<br />
an alternative solution was sought.<br />
Creating a physical barrier by using kerbing, was an attractive option. Kerbing was multipurpose: It provided a<br />
neat and tidy mowing edge which pleased the local residents and council, prevented the incursion of mowers<br />
into the bushland and also limited the spread of Couch. Several stories were circulating regarding the use of<br />
rubber conveyor belts buried into the ground vertically and used as barriers to stop rhizome and stolon<br />
spread. When a pre-used conveyor belt was donated by Wesfarmers, and the Lotteries Commission agreed to<br />
provide funding for the above-ground kerbing, the project was underway.<br />
An outline was created using a rope and marked with stakes. Making an early start, the City of Melville<br />
<strong>Bushland</strong> Works Crew, an enthusiastic Work for the Dole crew and EWAN project officers dug the trench, lay<br />
and buried the one metre wide conveyor belt. On several occasions there was grateful acknowledgment that<br />
the digging was in sand. In all, it took twelve people four hours. The only hiccups were several large Banksia<br />
roots, which were dug around, and the conveyor belt cut to fit. A contractor was brought in to do the kerbing,<br />
providing the finishing touch. With the donation of the conveyor belt, the labour or in-kind support, the project<br />
cost $1164 for 100 metres of barrier – this was all in the kerbing contractor’s fees.<br />
While the amenity grass already in the revegetation area still needs to be controlled, once it is eradicated it<br />
should be an easier job to keep new incursions out!<br />
15
16<br />
Chapter 3 Grass <strong>Weeds</strong><br />
Control techniques<br />
Annuals – prevent seed set and limit<br />
seedling establishment<br />
Highly disturbed areas are often dominated by annual<br />
grasses. Continual removal by physical or chemical<br />
means maintains the status quo. In degraded areas the<br />
control of annual grasses over the longer term requires<br />
the establishment of desirable vegetation (Refer to<br />
case study 5.1). However, undisturbed native plant<br />
communities are also susceptible to annual grass<br />
invasion, such as the understorey of York Gum –Jam<br />
woodlands.<br />
To control annual grasses it is essential to exhaust the<br />
soil seedbank and limit further seed recruitment. The<br />
most effective way of doing this is to prevent seed set<br />
or destroy seed before it is shed. The length of the<br />
control program will depend on the seed longevity<br />
within the soil. The following approaches can be<br />
successful if thoughtfully adopted:<br />
• Hand-weed small infestations occurring in good<br />
condition bushland. Remove weeds prior to seed<br />
set. Be aware that seeds can be spread during the<br />
weeding process and as contaminants of clothing<br />
and tools.<br />
• Slash prior to seed set. Timing is important; slash<br />
plants after the flower head has emerged but<br />
before seed is dry and ready for release. If slashed<br />
too early, plants will flower again. Flower heads<br />
must be bagged and removed as seed can continue<br />
to develop after removal from the plant. Slashing<br />
can be labour-intensive in bushland as it must be<br />
carefully done by hand to avoid damaging native<br />
plants.<br />
• Spray germinating weed grasses at the three to<br />
five leaf stage with the recommended rate of a<br />
grass selective herbicide. This approach may be<br />
difficult to apply to species that have staggered<br />
germination. Spray such species four to six weeks<br />
after rains begin to ensure maximum germination<br />
has occurred. Higher rates may be required and an<br />
even coverage harder to obtain.<br />
Research indicates Fusilade ® does not impact<br />
seriously on established perennial native grasses,<br />
although flowering is often inhibited. However,<br />
many native grass seedlings appear to be<br />
susceptible (Hobbs and Atkins 1988, Hitchmough<br />
et al. 1994, Davies 1997, Arnold et al. 1998, Brown<br />
and Brooks unpublished data).<br />
Note: For many years Fusilade ® has been the only grass selective<br />
herbicide registered for use in bushland in Western Australia and<br />
some annual grass species (Poa annua, Vulpia spp) are resistant to<br />
the ‘fops’ group of herbicides to which it belongs. With these<br />
problematic species alternatives should be sought (see weed<br />
management table).<br />
A number of other grass-selective herbicides are now the subject of<br />
a minor use off-label permit in non-crop situations in Western<br />
Australia (until September 2006). Application must comply with all<br />
conditions of the permit.<br />
Available from: (http://permits.nra.gov.au/PER4984.PDF).<br />
Anyone applying herbicides should have appropriate training in the<br />
safe use and handling of relevant chemicals (Chapter 8).<br />
• Prevent seedling establishment in highly degraded<br />
areas by encouraging the growth of native species<br />
and establishing a dense canopy cover. Most<br />
grasses prefer open sunny sites for germination.<br />
Perennial grass control<br />
Caespitose grasses<br />
• Hand-weed small populations in good condition<br />
bushland by using a knife to cut through the roots<br />
below the crown tissue. Minimise soil disturbance<br />
as much as possible. Care<br />
must be taken to remove all<br />
dormant buds at the base.<br />
These can break off and<br />
quickly form new plants. Many<br />
apparently caespitose species<br />
also produce short rhizomes<br />
which must be removed when<br />
hand-weeding, eg.<br />
Tribolium (Tribolium<br />
uniolae), Perennial Veldgrass,<br />
Vasey Grass. For Perennial<br />
Veldgrass, which grows in sandy<br />
soils, hand-removal in summer,<br />
when the grass is dormant and<br />
the roots easily cut through,<br />
minimises soil disturbance.<br />
• Spot spraying with a grass-selective herbicide<br />
controls many perennial grasses. These herbicides<br />
are highly selective for susceptible grasses and<br />
have little impact on most other species (Preston<br />
2000). In Banksia woodland on the Swan Coastal<br />
Plain, Fusilade ® (applied at 10 mL/L or 4 L/ha) has<br />
been found to have little impact on a wide range of<br />
native species (Brown unpubl., Dixon unpubl.)<br />
With established perennial grasses, grass-selective<br />
herbicides must be applied when the plant is<br />
actively growing but before boot stage (Parsons<br />
1995). Water stress and nutrient deficiencies can<br />
also be limiting factors to growth and must be<br />
taken into account. In some grasses the periods of<br />
vegetative growth and flowering are short and<br />
overlapping. In this scenario there may be little<br />
green leafy material prior to boot stage and<br />
alternative herbicides or different approaches will<br />
need to be tested. One option is the non-selective<br />
herbicide glyphosate, which if applied when the<br />
developing seed is still like milky dough, will stop<br />
seed development and kill the grass. Because<br />
glyphosate is non-selective the grass weed must<br />
be carefully targeted to avoid damage to<br />
surrounding natives. When spot spraying with any<br />
herbicide, grass clumps should be sprayed until<br />
wet, but without herbicide running off the leaves.<br />
The dead material retained on the caespitose<br />
grass provides protection to other leaves and may<br />
result in reduced herbicide uptake. Removing the<br />
dead material first (by slashing or taking<br />
advantage of unplanned fires) alleviates this<br />
problem. The lush regrowth that follows both<br />
these events is highly susceptible to herbicide.
• Slashing is generally used in conjunction with a<br />
herbicide treatment. Tussocks are slashed to the<br />
base to remove the bulk of old material and to<br />
promote vigorous growth; this should be done<br />
during the vegetative phase to maximise the<br />
regrowth of leafy green material. When regrowth is<br />
lush and vigorous, plants are spot sprayed with<br />
the appropriate herbicide. This method has been<br />
used successfully by the City of Canning on<br />
Pampas Grass invading Yagan Wetlands and is<br />
effective in dealing with many large, tussockforming<br />
species. Do not slash when grasses are<br />
seeding, as this will assist the spread of<br />
propagules locally.<br />
Continuous slashing of caespitose grasses during<br />
the transition phase (when shoot apices are at a<br />
vulnerable height) may exhaust their carbohydrate<br />
supply, eventually killing the plant. Although<br />
herbicide-free and causing minimal soil<br />
Box 3.5 Making the most of unplanned bushfires<br />
Chapter 3 Grass <strong>Weeds</strong><br />
disturbance this method requires accurate timing,<br />
consistent effort and in good bushland each plant<br />
must be slashed individually. Resources are rarely<br />
available for such intensive control.<br />
Note: Slashing without follow-up herbicide treatment may<br />
increase productivity of some grasses. This has been recorded for<br />
Buffel Grass in the United States (The Nature Conservancy, 2002)<br />
and appears to be true of African Lovegrass in the Perth region.<br />
• Unplanned fires require an intensive follow-up<br />
program. Resources should be allocated for<br />
controlling seedlings and resprouts before the<br />
grass problem increases (Box 3.5). Very hot fires<br />
can destroy seed close to the soil surface (Smith et<br />
al. 1999). This reduction in the soil seedbank must<br />
be maintained by preventing further seed set from<br />
resprouting plants and germinants. Vigorously<br />
resprouting plants provide an easy target in the<br />
blackened landscape and are readily treated and<br />
highly susceptible to herbicides.<br />
Talbot Road <strong>Bushland</strong> consists of 60 hectares of Banksia woodland, Marri, Jarrah and Wandoo woodlands and<br />
heath. Most is in good condition, but several infestations of weeds capable of moving further into undisturbed<br />
bushland are present. Perennial Veldgrass (Ehrharta calycina) was one such weed recognised as a problem in<br />
the sandier soils. In 1999 the Veldgrass was mapped and light infestations along tracks were hand-weeded to<br />
prevent spread into bushland. The presence of<br />
the cormous and bulbous weeds, Hesperantha<br />
(Hesperantha falcata), Freesia (Freesia alba x<br />
leichtlinii) and Watsonia (Watsonia bulbillifera),<br />
meant control of the main Perennial Veldgrass<br />
population was delayed until these serious<br />
weeds could be adequately managed.<br />
The Hesperantha, Freesia and Watsonia control<br />
programs had been in place for two years when, in<br />
the summer of 2000/2001, a fire burnt through<br />
some 70 % of the bushland. Part of the Perennial<br />
Veldgrass population was burnt and much of the<br />
remaining unburnt area was infested. Amid fears<br />
that the grass would quickly establish over a wider<br />
area, flourishing under the post-fire conditions,<br />
resources were made available for control.<br />
In July, following the fire, a contractor was<br />
employed to spray the remaining unburnt<br />
Perennial Veldgrass before seed set. Treating the<br />
area that had burnt was more complicated. The<br />
Perennial Veldgrass distribution map made in 1999<br />
was used to locate where the Perennial Veldgrass<br />
was. Resprouting clumps were carefully spot<br />
sprayed and seedling flushes blanket sprayed,<br />
taking care not to trample resprouting natives. The<br />
areas adjacent to the mapped populations and any<br />
gullies or wash areas were also carefully searched<br />
and seedling flushes treated. To minimise damage<br />
to native plants the grass selective herbicide<br />
Fusilade ® (10 mL/L) was used.<br />
Note: The susceptibility of Perennial Veldgrass seedlings to<br />
lower rates of Fusilade ® requires research. If lower rates were<br />
known to control the weed, the amount of herbicide introduced<br />
into the bushland could have been reduced.<br />
• 61 - 100% • 6 - 60% • 0 - 5% cover<br />
After the fire in December 2000 (lined area) a 1999 map of Perennial<br />
Veldgrass distribution at Talbot Road <strong>Bushland</strong> was used to determine<br />
priority areas for spraying in July 2001.<br />
17
18<br />
Chapter 3 Grass <strong>Weeds</strong><br />
Rhizomatous and stoloniferous grasses<br />
Hand-weeding should only be considered for very<br />
small infestations (less than one meter square) when<br />
soil is moist. It is important to remove all root, rhizome<br />
and stolon fragments or plants will rapidly regenerate.<br />
For some species like Para Grass and Johnson Grass,<br />
rhizomes can extend for up to two metres. However,<br />
because of the extensive soil disturbance involved,<br />
hand-weeding is generally not recommended in<br />
bushland.<br />
Herbicide can be blanket sprayed over the dense mats<br />
commonly formed by rhizomatous and stoloniferous<br />
grasses. A systemic herbicide that is translocated<br />
through all parts of the plant, including the rhizomes<br />
and stolons, must be used. Where native plants are<br />
present, grass-selective herbicides are necessary to<br />
avoid off-target damage. Without thorough foliage<br />
coverage, the amount of herbicide absorbed into the<br />
plant is not sufficient for effective control. Even with<br />
good coverage, many rhizomatous grasses require<br />
multiple spray treatments within a single season; only<br />
a few rhizomes or stolons need to survive for the plant<br />
to rapidly re-establish.<br />
Herbicide use near waterways becomes an important<br />
issue where many rhizomatous and stoloniferous<br />
grasses are invasive. At present Roundup Biactive ® is<br />
the only herbicide registered for use near water. Many<br />
of the wetlands of the Swan Coastal Plain are seasonal<br />
and dry up over the summer months. Luckily, summer<br />
coincides with the active growth of most wetland<br />
grasses and spraying can be done at this time. Grasses<br />
that grow in permanent water bodies will need to be<br />
either treated with Roundup Biactive ® or pulled from<br />
the water and methods such as solarisation tried.<br />
Solarisation is useful for controlling summer growing<br />
(C4) grasses in highly disturbed areas. This involves<br />
laying heavy duty plastic sheeting (black or clear) over<br />
part or all of the infested area. With edges firmly held<br />
down, the plastic is left in place for four to twelve<br />
weeks before being removed. The plastic sheeting<br />
traps the heat, increasing the soil temperature to levels<br />
that kill plants, seeds, plant pathogens and insects<br />
(Bainbridge 1990). The use of clear plastic results in<br />
higher soil temperatures, whereas black plastic<br />
prevents photosynthesis and this contributes to plant<br />
death. The method is most effective when applied<br />
during the hot summer months and is only really<br />
useful in sites where the soil is moist (Tu et al. 2001).<br />
The area may need to be blanket sprayed after any<br />
surviving grass has regrown vigorously.<br />
Establishing shade along bushland edges by<br />
encouraging the regeneration of local plants can inhibit<br />
the spread of many amenity grasses from adjacent<br />
parklands. Kikuyu, Buffalo Grass, Couch and similar<br />
amenity grasses are often intolerant of shade.<br />
Monitoring and follow-up<br />
It is important that grass control is done effectively<br />
and that any control program does not simply enhance<br />
the competitiveness of other serious weeds. With<br />
control programs for grass weeds in small urban<br />
bushlands costing up to $1000 per hectare, monitoring<br />
their success is essential.<br />
Monitoring provides a quantitative record of the<br />
management program, measures the impact of the<br />
control program on native plants and ensures value for<br />
money from contractors. How you monitor will depend<br />
on the changes to be detected, the type and patchiness<br />
of vegetation and the terrain. Case study 3.4 provides a<br />
detailed example of monitoring a Perennial Veldgrass<br />
control program in Banskia woodland.<br />
Regardless of the control method used, follow-up<br />
treatment in subsequent years is usually necessary.<br />
Plants that were missed or survived the first treatment<br />
will need treating and soil seedbanks may take several<br />
years to deplete. If follow-up does not take place, the<br />
initial effort and resources will be wasted.<br />
Key points<br />
The information presented in this chapter highlights a<br />
range of management issues concerning grass weeds and<br />
how these relate to the biology of this group. Briefly:<br />
• Invasion of many grasses is often facilitated by fire<br />
and loss of canopy cover.<br />
• Annual grasses are generally weeds of highly<br />
disturbed areas, although there are exceptions<br />
(Wild Oat, Annual Veldgrass). To control, prevent<br />
seed set over successive years and establish<br />
desirable vegetation.<br />
• Perennial grasses can threaten intact bushland.<br />
They are grouped into the tussock-forming<br />
caespitose grasses and the mat-forming<br />
rhizomatous or stoloniferous grasses. Management<br />
strategies and control techniques differ for the<br />
different growth forms.<br />
• Recognising and treating grasses at the<br />
appropriate growth stage is integral to a<br />
successful outcome of any control program.<br />
The case studies described below bring together this<br />
information, providing an example of management in<br />
action for an annual, a perennial caespitose and a<br />
rhizomatous grass. A fourth case study describes the<br />
monitoring of a Perennial Veldgrass control program<br />
at Blue Gum Lake. Following the case studies is a<br />
table of currently available information on the control<br />
of grass weeds.<br />
One aspect of their biology that has contributed<br />
greatly to the success of the grasses is the ability to<br />
store carbohydrate reserves in tillers and rhizomes at<br />
the base of the plant. This strategy is taken even<br />
further by the group of plants covered in the next<br />
chapter. The bulbous, cormous and tuberous species<br />
are another group successfully naturalising in south<br />
west Western Australia. Their success, in part, is due<br />
to an ability to die back to underground storage organs<br />
over our long dry summers.
An informative case study on the<br />
control of the annual grasses Wild<br />
Oat (Avena barbata) and Blowfly<br />
Grass (Briza maxima) within<br />
bushland comes from a trial at<br />
Quairading Nature Reserve. Wild<br />
Oat and Blowfly Grass are wintergrowing<br />
annuals that rely on<br />
successful seed set and recruitment<br />
into the soil seedbank to persist.<br />
The aim of the trial was to reduce, if<br />
not eliminate the Wild Oat<br />
seedbank, and give a competitive<br />
advantage to the native annual herb<br />
and perennial grass species. The<br />
possibility that other annual or<br />
perennial weeds would fill the niche<br />
also required consideration and a<br />
monitoring program was put in<br />
place to record changes in<br />
vegetation cover and species<br />
diversity over time.<br />
Setting up the<br />
demonstration site<br />
The trial was designed to reduce<br />
external seed contamination from<br />
surrounding weed grasses. Changes<br />
in weed, native grass and herb<br />
cover were monitored over three<br />
years and the effectiveness of direct<br />
seeding evaluated.<br />
The design: Two large, 20 metre<br />
square permanent plots, a control<br />
and a treatment, each housed five<br />
randomly placed one metre square<br />
quadrats. A third 20 metre square<br />
plot, for testing direct seeding, was<br />
established in the second year of<br />
the trial. It housed ten one metre<br />
square quadrats of which half were<br />
used for controls.<br />
Treatment: Fusilade ® (500mL/ha) +<br />
Pulse ® (2 mL/L) was blanket sprayed<br />
over the treatment and direct<br />
seeding plots in early August when<br />
the Wild Oat was at the three to five<br />
leaf stage and around 10 cm high<br />
(Table 1). A local farmer carried out<br />
the spraying.<br />
In August 2000, direct seeding trials<br />
were carried out by sowing native<br />
seed collected from the site over<br />
the 20 m x 20 m quadrat apart from<br />
five of the 10 subquadrats (1 m x 1<br />
m) which were covered during the<br />
sowing. These were the controls.<br />
Seed was from a range of annual<br />
Chapter 3 Grass <strong>Weeds</strong> Case Studies<br />
Case study 3.1 Managing the annual grasses Wild Oat (Avena barbata) and Blowfly Grass<br />
(Briza maxima) at Quairading Nature Reserve<br />
herbs and perennial grasses<br />
including Neurachne alopecuroidea,<br />
Austrostipa elegantissima,<br />
Austrostipa tenuifolia, Waitzia<br />
acuminata and Rhodanthe manglesii.<br />
Data collected: Each year, in late<br />
spring, weed and native species<br />
present in each quadrat were<br />
recorded, counted and their<br />
percentage cover estimated and<br />
assigned to a cover class: 1 (
20<br />
Chapter 3 Grass <strong>Weeds</strong> Case Studies<br />
grass weeds. It didn’t. Silver Grass<br />
cover remained low throughout the<br />
three year trial period, as did cover<br />
of Silvery Hairgrass.<br />
In contrast, Annual Veldgrass<br />
seedlings are susceptible to<br />
Fusilade ® (Davies 1997, Brown<br />
unpublished data) and like Wild<br />
Oat, germination is in the few weeks<br />
following the opening rains (Davies<br />
1997). Like Wild Oat, two years of<br />
treatment appeared to exhaust the<br />
soil seedbank of Annual Veldgrass<br />
at the site. However, there was an<br />
indication that a single treatment<br />
could result in Annual Veldgrass<br />
becoming a serious weed in the<br />
absence of Wild Oat competition.<br />
Non-grass weeds: In total, there<br />
were 12 weeds present at the site,<br />
including the Wild Oat and Blowfly<br />
Grass - none were invasive<br />
perennials. Only Flatweed<br />
(Hypochaeris glabra) and Ursinia<br />
(Ursinia anthemoides) showed a<br />
noticeable response to the removal<br />
of Wild Oat and Blowfly Grass. The<br />
number of Flatweed plants<br />
increased within the treatment plot<br />
by over 30 % from 1999 to 2001, but<br />
decreased in the control by 80 %.<br />
This suggests Flatweed has a<br />
stronger competitive advantage<br />
than the native annual flora, but is<br />
weaker against Wild Oat and<br />
Blowfly Grass, especially in poor<br />
years when moisture is scarce.<br />
The native flora<br />
As the 1999 season unfolded, colour<br />
erupted in the sprayed plot (Figure<br />
2). A mass flowering of native<br />
annuals occurred. These species,<br />
while found in the unsprayed plot,<br />
were largely smothered there by<br />
Wild Oat and Blowfly Grass.<br />
Native annual and perennial<br />
herbs: There was little indication<br />
that the Fusilade ® harmed the native<br />
annual and geophyte flora. The<br />
decrease in competition from Wild<br />
Oat and Blowfly Grass appears to<br />
have benefited the geophyte lifeform<br />
over time. Initially geophyte<br />
numbers were significantly lower in<br />
the treatment plot, but, after two<br />
years of treatment, numbers were<br />
similar in both plots.<br />
Two native annual herbs apparently<br />
affected by the density of Wild Oat<br />
and Blowfly Grass were Waitzia<br />
acuminata and Phyllangium<br />
sulcatum. Both species decreased in<br />
the control plot over the three<br />
years and remained similar<br />
(P. sulcatum) or increased<br />
(W. acuminata) in the treatment plot.<br />
Native grasses: Mature clumps of<br />
eight native grasses (Aristida<br />
contorta, Austrodanthonia<br />
caespitosa, Austrodanthonia setacea,<br />
Austrostipa elegantissima,<br />
Austrostipa tenuifolia, Austrostipa<br />
trichophylla, Eriachne ovata,<br />
Neurachne alopecuroidea) suffered<br />
only temporarily from the herbicide<br />
treatment. Seedling recruitment<br />
observed in 2001 suggests that the<br />
removal of competition by Wild Oat<br />
and Blowfly Grass will allow native<br />
grasses to become more dominant<br />
over time.<br />
Figure 2. Looking back over the treatment plot in October 1999 - a profusion of wild flowers.<br />
Herbicide treatment appeared to<br />
inhibit flowering in the native<br />
grasses. Aristida contorta and<br />
N. alopecuroidea in particular<br />
flowered profusely outside the<br />
treatment plot, while flowers were<br />
all but absent on tussocks inside<br />
the plot. A reduction in flowering of<br />
native grasses after Fusilade ®<br />
treatment has also been recorded in<br />
a study by Hitchmough et al. (1994).<br />
Although this and other studies<br />
(Hitchmough et al. 1994, Davies<br />
1997) indicate mature native<br />
grasses only suffer temporary<br />
adverse effects to Fusilade ®<br />
treatment, impacts need to be<br />
carefully monitored. Fusilade ® is<br />
highly phytotoxic at the 3-5 leaf<br />
stage on most native grasses tested<br />
(Hitchmough et al. 1994). The<br />
continued treatment of an area may<br />
inhibit recruitment of native grasses<br />
and inevitably lead to a reduction in<br />
native grass cover and local<br />
diversity.<br />
Direct seeding trials<br />
The aim of the direct seeding trial<br />
was to tip the competitive balance<br />
in favour of the native flora. Exotic<br />
grasses were controlled with the<br />
early herbicide treatment and the<br />
native seedbank was boosted by<br />
direct seeding with locally collected<br />
native herb and grass species. The<br />
direct seeding trial plot was both<br />
species-poor and had low cover and<br />
numbers of native plants. Following<br />
the direct seeding of native herbs<br />
and grasses in August 2000 there<br />
was no significant, or indeed<br />
obvious, increase in these figures.<br />
The failure of the sown seeds to<br />
germinate can be attributed to a<br />
number of factors. Although the<br />
seeds were viable, the dry winter<br />
and lack of soil moisture may have<br />
inhibited germination. Large<br />
amounts of seed may have blown<br />
away. It is important to note that<br />
any sort of soil disturbance that<br />
may have enhanced germination of<br />
broadcast seed would also enhance<br />
weed invasion. Time of sowing, seed<br />
treatment and lack of surface<br />
preparation may all be wholly, or<br />
partly responsible. It is possible<br />
that the site itself did not favour the<br />
germination of annual herbs; there<br />
were very few areas of bare soil<br />
within the plot. Further research<br />
into direct seeding in these<br />
woodlands is clearly required.
Conclusion<br />
Overall the demonstration site and<br />
trials were a success. Wild Oat,<br />
Blowfly Grass and Annual Veldgrass<br />
soil seedbanks were depleted by<br />
two years of treatment. In the right<br />
situation native herbs flourished in<br />
the absence of Wild Oats and native<br />
grasses did not suffer permanent<br />
damage. Other annual weeds failed<br />
to become a serious problem and<br />
with continued research into direct<br />
seeding, the competitiveness of the<br />
native plant community could be<br />
further enhanced.<br />
Tribolium (Tribolium uniolae), a<br />
tussock-forming perennial grass, is<br />
a native of South Africa where it is<br />
found in the winter rainfall areas of<br />
the Cape Province. A highly variable<br />
species, this grass appears able to<br />
exploit new habitats where they<br />
arise. Common as a ‘roadside weed’ it<br />
successfully invades disturbed<br />
ground and responds positively to<br />
scrub fires (Linder and Davidse 1997).<br />
At Brixton Street Wetlands<br />
Tribolium is invading Marri<br />
woodlands, herb-rich shrublands<br />
and to a lesser degree claypans.<br />
Large clumps are displacing the<br />
very rich annual and perennial<br />
herbaceous flora that grows there.<br />
In the past Tribolium has been<br />
successfully treated at Brixton<br />
Street with the non-selective<br />
herbicide Roundup ® at 10 mL/L.<br />
Recently the weed was recorded<br />
spreading into undisturbed<br />
bushland so more selective control<br />
methods were required.<br />
Herbicide trials and<br />
standing water<br />
Some areas of Brixton Street are<br />
inundated for part of the year and<br />
herbicide application can be<br />
inappropriate. Unfortunately, when<br />
the wetlands are dry from January<br />
through to May, Tribolium is<br />
usually dormant. Active growth<br />
starts in June following the first<br />
rains and by the time the wetlands<br />
begin to dry out in late October,<br />
flowering is underway.<br />
Chapter 3 Grass <strong>Weeds</strong> Case Studies<br />
Applying this information<br />
to the control of other<br />
annual grasses<br />
Seedbank persistence is indicative<br />
of the required length of the<br />
control program.<br />
Using this approach to control<br />
grasses with more persistent<br />
seedbanks may severely impact on<br />
native grasses.<br />
A single spray early in the season<br />
will not be so effective on weed<br />
grass species with staggered<br />
germination.<br />
Figure 1. Tribolium growing in the bushland at Brixton Street.<br />
It is important to know what other<br />
opportunistic weed species may<br />
take advantage of the space<br />
created by removal of annual<br />
grass weeds. It is unwise to<br />
remove an annual grass if it will<br />
lead to establishment of a more<br />
serious weed.<br />
In many circumstances the<br />
removal of annual grasses may<br />
leave bare areas of ground that are<br />
open to invasion. In these<br />
circumstances direct seeding may<br />
be appropriate.<br />
Case study 3.2 Managing the perennial caespitose grass, Tribolium (Tribolium uniolae),<br />
invading threatened ecological communities in the Brixton Street Wetlands.<br />
Grass-selective herbicides should<br />
normally be applied before the<br />
boot stage (Parsons, 1995).<br />
However, the issue of standing<br />
water was important so it became<br />
necessary to investigate an<br />
application at the post-boot stage.<br />
The initial herbicide trials took<br />
place in November. There was still<br />
plenty of leaf material, but plants<br />
were flowering. Two different grassselective<br />
herbicides, Fusilade ® and<br />
Sertin Plus ® , both with the addition<br />
of Pulse ® , were tested on older<br />
plants (characterised by much<br />
dead material surrounding a few<br />
actively growing leaves and stems)<br />
and younger plants (mostly leafy<br />
green material).<br />
21
22<br />
Chapter 3 Grass <strong>Weeds</strong> Case Studies<br />
The trials were simple: Five sets of<br />
three 2 m x 2 m quadrats were set<br />
up within a population of mature<br />
plants (five Fusilade ® , five Sertin<br />
Plus ® and five control plots). For the<br />
younger plants, which occurred at<br />
much higher densities, three sets of<br />
three 1 m x 1 m plots were used.<br />
Plants were counted prior to<br />
treatment and scored again after<br />
the emergence of green material the<br />
following June.<br />
Older plants Given the small<br />
number of actively growing leaves,<br />
older plants were perceived as<br />
difficult to kill and Fusilade ® was<br />
applied at a high rate (15 mL/L).<br />
Both herbicides tested on mature<br />
flowering plants were effective,<br />
particularly the Fusilade ® treatment<br />
in which no plants survived.<br />
However, only 48.3 % of plants in<br />
the control plots survived the trial<br />
period (Table 1). The high levels of<br />
natural senescence may be the<br />
result of an extremely dry summer<br />
or simply reflect the age of the<br />
population, factors that may also<br />
have contributed to the high death<br />
rate in the treatment plots.<br />
Younger plants Herbicide applied<br />
during flowering (November 2000)<br />
was ineffective on younger plants.<br />
Further trials were conducted in<br />
August when plants were actively<br />
growing yet not quite flowering (ie.<br />
before the boot stage). This time<br />
herbicide treatment was effective<br />
(Table 2). The presence of standing<br />
water limits Fusilade ® application<br />
to dry areas.<br />
Fire<br />
In January 2000 an unplanned fire<br />
burnt through the southern section<br />
of Brixton Street destroying earlier<br />
herbicide trials. However, pre- and<br />
post- fire counts of Tribolium<br />
plants in the control plots provided<br />
useful data on the weed’s response<br />
to fire. An average of only 26 % of<br />
plants resprouted following the fire,<br />
but by June 2000 an abundance of<br />
seedlings was observed in the plots<br />
and surrounding burnt area.<br />
The fire provided an excellent<br />
control opportunity. As well as<br />
killing 74 % of plants in the plots,<br />
the remaining plants were<br />
vigorously producing tillers before<br />
the break of season and winter<br />
rainfall. This was also well before<br />
most of the native vegetation had<br />
begun to recover from the fire. In<br />
the blackened landscape the green<br />
Tribolium plants were highly visible<br />
and easy targets for spraying<br />
(Figure 2).<br />
In May 2000 the effectiveness of<br />
Roundup ® and Fusilade ® (both 10<br />
mL/L) at controlling plants<br />
resprouting from burnt clumps was<br />
compared. The number of actively<br />
growing plants in three sets of three<br />
2 m x 2 m plots (three controls,<br />
three Fusilade ® , three Roundup ® )<br />
were counted before, and then six<br />
weeks after treatment. At the time<br />
of treatment Tribolium plants in<br />
unburnt vegetation were still in the<br />
dry dormant stage with no visible<br />
green growth.<br />
Both herbicide treatments were<br />
effective. A mean of only 2.2 %<br />
survived the Roundup ® treatment<br />
and a mean of 5.4 % the Fusilade ®<br />
treatment (Table 3). Furthermore,<br />
seedlings that were prolific in postfire<br />
vegetation were effectively<br />
controlled with Fusilade ® at 10 mL/L.<br />
Table 1. Mean percentage of Tribolium plants surviving in trial plots following herbicide treatments on older flowering plants.<br />
TREATMENT GROWTH STAGE DATE MEAN SURVIVAL (%) SE +/-<br />
Fusilade 15 mL/L + Pulse 2 mL/L older plants, flowering Nov 2000 0<br />
Sertin Plus 12 mL/L + Pulse 2 mL/L 19.5 5.74<br />
Control 48.3 14.7<br />
Table 2. Mean percentage of Tribolium plants surviving in trial plots following herbicide treatments on younger plants at flowering<br />
and just prior tp flowering.<br />
TREATMENT GROWTH STAGE DATE MEAN SURVIVAL (%) SE +/-<br />
Fusilade 10 mL/L + Pulse 2 mL/L younger plants, flowering Nov 2000 54.2 11.29<br />
Sertin Plus 12 mL/L + Pulse 2 mL/L 56.3 5.6<br />
Control 88.8 14.7<br />
Fusilade 10 mL/L + Pulse 2 mL/L younger plants, prior to flowering Aug 2001 3.9 0.93<br />
Fusilade 10 mL/L + DC-trate 2 mL/L 11.3 4.83<br />
Control 96.4 2.48<br />
Table 3. Mean percentage of Tribolium plants surviving in trial plots following herbicide treatments on plants resprouting after a<br />
January fire. Value greater than 100 % indicates recruitment.<br />
TREATMENT GROWTH STAGE DATE MEAN SURVIVAL (%) SE +/-<br />
Fusilade 10 mL/L + Pulse 2 mL/L resprout from Jan 2000 fire May 2000 5.4 2.9<br />
Roundup 10 mL/L + Pulse 2 mL/L 2.2 5.12<br />
Control 100.8 5.1
Figure 2. Tribolium vigorously resprouting after fire.<br />
Hand-weeding<br />
Physical removal of Tribolium by<br />
cutting below the base with a sharp<br />
knife is one option appropriate for<br />
small, isolated populations when<br />
the soil is moist. However, this<br />
method is labour intensive and<br />
impractical on a larger scale. Where<br />
the grass grows very closely among<br />
native plants it is difficult to remove<br />
without damaging native vegetation.<br />
The effectiveness of hand-weeding<br />
is somewhat compromised by the<br />
ability of Tribolium to reproduce<br />
from small, adventitious buds that<br />
break off from the base.<br />
Management<br />
Effective management of Tribolium<br />
invading bushland relies on control<br />
of mature plants as well as<br />
subsequent seedling recruits. It is<br />
clear that the weed can be<br />
effectively controlled with grassselective<br />
herbicides. However,<br />
chemical control of established<br />
plants is only going to be one part<br />
of any strategy.<br />
As well as understanding how to<br />
control Tribolium, it is important to<br />
understand how the weed is<br />
dispersing and spreading. At<br />
Brixton Street dispersal is by the<br />
seed, which is light in weight and<br />
small in size. Sheet water flow<br />
occurring across the wetlands in<br />
winter probably carries seed into<br />
undisturbed bushland. Ants may<br />
also be moving seed around, with<br />
seedling recruitment consistently<br />
Chapter 3 Grass <strong>Weeds</strong> Case Studies<br />
observed around their nests<br />
(Figure 3).<br />
Keeping fire and other disturbances<br />
out of the bushland is essential to<br />
stop the spread of Tribolium.<br />
Seedlings are able to exploit space,<br />
light and nutrients, made available<br />
by fire, establishing early and outcompeting<br />
regenerating native<br />
species. Any unplanned fire,<br />
however, should be taken as an<br />
opportunity to effectively control<br />
mature plants and the subsequent<br />
seedlings. Without follow-up control<br />
of germinants, fire will almost<br />
certainly contribute to the further<br />
spread of Tribolium in the bushland.<br />
Figure 3. Tribolium plants growing vigorously around an ant nest.<br />
Over the winter of 2001, seedling<br />
recruitment was also observed in<br />
plots where there had been high<br />
levels of senescence among mature<br />
plants (both natural and as a result<br />
of herbicide treatments). As tufts of<br />
perennial grasses die back, gaps are<br />
created that are available for<br />
colonisation by seedlings (O’Connor<br />
and Everson 1998). Using baseline<br />
distribution maps of the weed, it<br />
will be necessary to systematically<br />
monitor the bushland for seedling<br />
recruitment over a number of years.<br />
Knowing how long seed remains<br />
viable in the soil is important in<br />
management planning for follow-up<br />
work and is an area requiring<br />
further research.<br />
The management focus at Brixton<br />
Street is protection of the native<br />
plant communities, not just<br />
eradication of Tribolium.<br />
Consequently, plant species moving<br />
into the gap created as the weed is<br />
removed will need to be carefully<br />
monitored. There are other serious<br />
perennial weeds invading the<br />
wetlands that have the potential to<br />
recolonise the treated sites,<br />
including Harlequin Flower (Sparaxis<br />
bulbifera), Watsonia species,<br />
Gladiolus undulatus and African<br />
Lovegrass (Eragrostis curvula). These<br />
are all subject to fairly intensive<br />
control programs at present.<br />
Source: Brown and Brooks<br />
(In press a)<br />
23
24<br />
Chapter 3 Grass <strong>Weeds</strong> Case Studies<br />
Case study 3.3 Managing the rhizomatous Reed Sweet Grass (Glyceria maxima)<br />
at Gingin Brook<br />
Reed Sweet Grass (Glyceria<br />
maxima) was introduced to<br />
Australia as a pasture grass for<br />
continuously and seasonally wet<br />
areas (Humphries et al. 1991).<br />
However, in Australia and New<br />
Zealand it accumulates toxic levels<br />
of hydrocyanic acid, which has<br />
resulted in cattle deaths from<br />
cyanide poisoning (DPIWE 2001).<br />
A grass of temperate regions, Reed<br />
Sweet Grass rapidly became a weed<br />
of waterways and wet meadows in<br />
southern Australia (Humphries et al.<br />
1991, DPIWE 2001). Reaching heights<br />
of over two metres, this robust<br />
perennial is capable of rapidly<br />
forming large infestations. Factors<br />
contributing to its success include:<br />
• Prolific seeding throughout<br />
summer and autumn especially<br />
in newly establishing<br />
populations (DPIWE 2001).<br />
• Varying levels of dormancy<br />
(immediate germination<br />
through to dormancy for<br />
several years) (DPIWE 2001).<br />
• Development by seedlings of an<br />
extensive mat of roots and<br />
rhizomes in the first year of<br />
growth (DPIWE 2001).<br />
• Quick expansion from the mat<br />
of rhizomes, or underground<br />
stems, which comprise 40-55 %<br />
of the plant’s total biomass<br />
(DPIWE 2001).<br />
• Growth in mats on water to one<br />
metre deep, out-competing<br />
native aquatic plants.<br />
• Spread of seed and rhizome<br />
fragments in water, in mud on<br />
machinery and vehicles, on<br />
footwear and by livestock.<br />
In Tasmania, a common control<br />
method for larger infestations is<br />
foliar spray using a 1-3 % solution of<br />
glyphosate (Roundup Biactive ® )<br />
during late summer through to early<br />
autumn. Translocation of<br />
photosynthates, and thus herbicide,<br />
may be best at this time; the plant<br />
is storing carbohydrates in the<br />
rhizomes in preparation for<br />
overwintering and growth in the<br />
following season (DPIWE 2001).<br />
Follow-up treatments early in the<br />
following summer are recommended.<br />
Plants that have more than about<br />
one-third of their stems below water<br />
might not be killed by herbicide.<br />
Reed Sweet Grass at<br />
Gingin Brook<br />
Reed Sweet Grass is one of several<br />
serious weeds invading the last<br />
remaining Flooded Gum (Eucalyptus<br />
rudis) – Swamp Paperbark<br />
(Melaleuca rhaphiophylla)<br />
woodlands fringing the Gingin<br />
Brook. With very little natural<br />
vegetation remaining along the<br />
brook, it was important to<br />
implement a management strategy<br />
that would remove the grass and<br />
allow the native flora to recolonise<br />
the area. Because the grass grows<br />
closely amongst native vegetation,<br />
the use of a non-selective herbicide<br />
was inappropriate.<br />
Treatment: To observe the<br />
effectiveness of the grass-selective<br />
herbicide Fusilade ® at controlling<br />
Reed Sweet Grass, a single 5 m x 5<br />
m plot was permanently marked.<br />
The percentage cover of natives<br />
and weeds was recorded and the<br />
grass sprayed with Fusilade ® 10<br />
mL/L plus Agral ® 3.5 mL/L late in<br />
February, 2000.<br />
Results: Before treatment, Reed<br />
Sweet Grass covered 90 % of the<br />
plot while the native Tassel Sedge<br />
(Carex fascicularis) and Tall Sedge<br />
(Carex appressa) covered the<br />
remaining 10 %. By November 2000,<br />
Reed Sweet Grass covered only 25 %<br />
of the plot and most of this<br />
appeared to be reinvasion from the<br />
edges. Tassel Sedge and Tall Sedge<br />
now covered 25 % of the plot and a<br />
carpet of Carex seedlings and the<br />
occasional Flooded Gum and Swamp<br />
Paperbark seedling were recorded.<br />
Scaling up: Given the encouraging<br />
results, it was decided to spray the<br />
whole population with 10 mL/L<br />
Fusilade ® and Pulse ® . The trial plot<br />
was also resprayed. It was planned<br />
Reed Sweet Grass forms a dense mass across the trial plot and surrounding areas. Reed Sweet Grass extending stolons into a<br />
bare area.
to spray the infestation twice over<br />
summer – when the area was dry.<br />
Therefore, in contrast to the latesummer<br />
spray within the trial plot,<br />
the initial treatment was carried out<br />
in early summer (November 2000).<br />
By February 2000, cover of Reed<br />
Sweet Grass within the trial plot<br />
(now sprayed twice) was reduced<br />
to 5 %, Carex cover remained at<br />
25 % and there were still many<br />
Carex seedlings. There was also an<br />
array of annual weeds and two<br />
perennial weeds flourishing in the<br />
bare soil. Outside the trial plot was<br />
At Blue Gum Lake, plots were put in<br />
to record the effectiveness of a<br />
Perennial Veldgrass (Ehrharta<br />
calycina) control program and to<br />
answer the question ‘what will<br />
return once Perennial Veldgrass<br />
is controlled?’.<br />
The four year control program<br />
adopted an integrated approach.<br />
Contractors sprayed the dense<br />
infestations with Fusilade ® at 4 L/ha<br />
and the Friends of Blue Gum Lake<br />
hand-weeded light infestations one<br />
day each summer in the areas of<br />
good bushland. Maps of the grass<br />
distribution and density, created<br />
prior to and after the control<br />
program, provided a broad measure<br />
of effectiveness (Figure 1a and 1b).<br />
The Veldgrass density was<br />
estimated for 20 metre squares on a<br />
grid basis over the bushland.<br />
Permanently marked plots to<br />
monitor the changes in vegetation<br />
composition, quantify the success<br />
of the spray program and assess<br />
the spray contractor’s efficiency<br />
were put in place in August 1998.<br />
Five treatment and five control<br />
plots (each two metres by two<br />
metres) were set up within a<br />
densely infested area (Figure 2).<br />
Mature and seedling Veldgrass<br />
plants were counted. All other<br />
species were recorded and the<br />
percentage cover of weed species<br />
within each plot estimated. When<br />
the infestation was sprayed the<br />
control plots were left untouched.<br />
Each year, all plots were re-scored<br />
immediately prior to treatment.<br />
Chapter 3 Grass <strong>Weeds</strong> Case Studies<br />
a different story. Although Reed<br />
Sweet Grass was damaged by the<br />
November treatment, there was<br />
still substantial cover across the<br />
area. The November treatment was<br />
clearly not as effective as the late<br />
February treatment had been. This<br />
may have resulted from the<br />
different treatment time or the use<br />
of a different wetting agent. Some<br />
Carex plants were also damaged.<br />
Unfortunately the second herbicide<br />
application planned for late<br />
summer could not be made due to<br />
early rains that inundated the area.<br />
• 0 - 5% • 6 - 20% • 21 - 60% • 61 - 100% cover<br />
Management implications: This<br />
case study illustrates the possible<br />
importance of timing and wetting<br />
agent used in determining the<br />
outcome of a particular treatment.<br />
Before scaling up it is important to<br />
consider all factors when looking at<br />
the results of trials.<br />
Note: Reed Sweet Grass quickly becomes a<br />
large and vigorous plant and new<br />
infestations should be treated immediately. If<br />
control is delayed, eradication in one season<br />
is improbable and follow-up work over at<br />
least two or three seasons will be required<br />
(DPIWE 2001).<br />
Case study 3.4 Monitoring the effect of Fusilade ® treatment on Perennial Veldgrass<br />
(Ehrharta calycina) and the native plant community in a Banksia woodland<br />
a<br />
b<br />
Figure 1. Perennial Veldgrass density and distribution at Blue Gum Lake in 1999 (a) and 2001 (b).<br />
25
26<br />
Chapter 3 Grass <strong>Weeds</strong> Case Studies<br />
Figure 2. One of the 2 m x 2 m plots set up to monitor the Perennial Veldgrass control program at Blue Gum Lake<br />
In 1998 the spray contractors were<br />
not available to treat the grass until<br />
early September – well past the<br />
peak growth period and after the<br />
plants had begun to flower. The kill<br />
rate was disappointing and not<br />
surprising given that Fusilade ®<br />
should be applied pre-boot stage.<br />
This was discussed with the<br />
contractors who agreed to address<br />
the matter. In 1999 the contractors<br />
sprayed in June, which is too early!<br />
It was not until 2000 that the plants<br />
were sprayed at the correct time –<br />
just before flowering, in mid July.<br />
Research at Kings Park, Perth, has<br />
shown how crucial timing is for the<br />
control of Perennial Veldgrass<br />
(Dixon 1998a). It is important to<br />
wait until the majority of the new<br />
season’s adventitious buds are<br />
actively growing to allow sufficient<br />
herbicide to be taken into the plant,<br />
but not leave it so long that<br />
flowering has begun. The results<br />
from monitoring plots provided the<br />
evidence to both contractors and<br />
local council about the importance<br />
of timing (Figure 3(a)).<br />
Results from counts of seedlings<br />
showed the expected high numbers<br />
following the wildfire in the year<br />
previous to the trials (Figure 3(b)).<br />
Fire is known to enhance<br />
germination of Perennial Veldgrass<br />
seed (Milberg and Lamont 1995,<br />
Myut 2001). The much lower<br />
numbers in the control plots in<br />
subsequent years suggests that<br />
Veldgrass recruitment may be<br />
density dependent, competition<br />
from the resprouting adults limiting<br />
seedling establishment.<br />
Mean number of mature Veldgrass plants<br />
60<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
control<br />
treatment<br />
1998 1999 2000 2001<br />
Year<br />
a<br />
Less obvious were the changes in<br />
species composition. In terms of<br />
presence or absence there were no<br />
apparent differences between<br />
control and treatment plots.<br />
Ursinia (Ursinia anthemoides)<br />
increased in cover in the last year<br />
(2001), but observations from<br />
other bushland sites in the Perth<br />
area suggest this was a good year<br />
for the weed. Flatweed<br />
(Hypochaeris glabra) cover<br />
Figure 3. Mean number of mature Perennial Veldgrass clumps (a) and Perennial Veldgrass<br />
seedlings (b) in control and treatment plots at Blue Gum Lake from 1998 to 2001.<br />
Mean number of Veldgrass seedlings<br />
60<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
1998 1999 2000 2001<br />
Year<br />
b<br />
control<br />
treatment
fluctuated throughout the period<br />
and all other weeds reduced in<br />
cover or remained similar. There<br />
was no influx of weeds following<br />
the Veldgrass removal which was<br />
encouraging – but nor was there an<br />
increase in native germination.<br />
Chapter 3 Grass <strong>Weeds</strong> Case Studies<br />
Table 1. Native species occurring in the monitoring plots unaffected by the Fusilade ® treatment.<br />
Annual herbs<br />
Crassula colorata<br />
Homalosciadium homalocarpum<br />
Lobelia tenuior<br />
Perennial herbs<br />
Conostylis aculeata<br />
Desmocladus fasciculatus<br />
Desmocladus flexuosa<br />
Dianella revoluta<br />
Isotropis cuneifolia<br />
Lepidosperma angustatum<br />
Lepidosperma spp<br />
Lomandra caespitosa<br />
Lomandra hermaphrodita<br />
Lomandra preissii<br />
Lomandra sp.<br />
Lyginia barbata<br />
Opercularia vaginata<br />
Patersonia occidentalis<br />
Phlebocarya ciliata<br />
Schoenus curvifolius<br />
Tricoryne elatior<br />
Perennial herbs-geophytes<br />
Burchardia congesta<br />
Caesia micrantha<br />
Drosera menziesii ssp menziesii<br />
Microtis media<br />
Pyrorchis nigricans<br />
Sowerbaea laxiflora<br />
Thysanotus manglesianus<br />
The impacts of grass-specific<br />
herbicides on native plant<br />
communities are thought to be<br />
minimal. The sedges, rushes and<br />
many geophytes (orchids, native<br />
lilies, etc.) which are monocots like<br />
grasses, may however be<br />
particularly susceptible. From<br />
monitoring of plots at Blue Gum<br />
Lake it appears that Fusilade ®<br />
applied between June and<br />
September, has little impact on a<br />
range of native species (Table 1).<br />
Perennial grasses<br />
Austrodanthonia caespitosa<br />
Austrostipa compressa<br />
Shrubs<br />
Acacia stenoptera<br />
Bossiaea eriocarpa<br />
Dampiera linearis<br />
Dasypogon bromeliifolius<br />
Eriostemon spicatus<br />
Eucalyptus calophylla<br />
Gompholobium aristatum<br />
Gompholobium tomentosum<br />
Hardenbergia comptoniana<br />
Hibbertia hypericoides<br />
Hibbertia racemosa<br />
Hovea pungens<br />
Hovea trisperma<br />
Hypocalymma robustum<br />
Jacksonia furcellata<br />
Kennedia prostrata<br />
Lechenaultia floribunda<br />
Leptomeria empetriformis<br />
Macarthuria australis<br />
Petrophile linearis<br />
Pimelea rosea<br />
27
Chapter 3 Grass <strong>Weeds</strong> Management Table<br />
Species<br />
Alopecurus<br />
myosuroides<br />
Common name Lifeform Growth<br />
form<br />
28<br />
Photosynthetic<br />
pathway<br />
Staggered<br />
germination<br />
Growing<br />
season<br />
Flowering Reproductive unit Dispersal agent Seedbank persistence<br />
(years)<br />
Slender Foxtail a c C3 win-spr spr seed mammal 4+<br />
Ammophila arenaria Marram Grass p r C3 spr? spr-sum rhizome (seed) water, wind,<br />
mammal<br />
Anthoxanthum<br />
odoratum<br />
Sweet Vernal Grass p r/c C3 win-spr spr-sum seed, rhizomes water, wind, bird,<br />
mammal, slash<br />
Arundo donax Giant Reed p r C3 spr-aut sum rhizomes, (seed) water<br />
(bird, wind)<br />
(some seed/seed sterile?)<br />
short-med-long?<br />
(rarely seeds)<br />
Avena barbata Bearded Oat a c C3 no win-spr spr seed mammal, wind 3+ (shorter unburied)<br />
Avena fatua Wild Oat a c C3 yes win-spr spr seed mammal, wind 10 (shorter unburied)<br />
Axonopus compressus Broad-leaved Carpet<br />
Grass<br />
Brachypodium<br />
distachyon<br />
Briza spp<br />
(B. maxima, B. minor)<br />
p r/s C4 spr-sum sum-aut seed, stolon wind short<br />
False Brome a c C3 aut-win spr seed mammal, wind<br />
Blowfly Grass a c C3 no late<br />
aut-win<br />
spr seed water, wind,<br />
mammal, slash<br />
Bromus diandrus Great Brome a c C3 win-spr spr seed mammal, wind short<br />
Bromus hordeaceus Soft Brome a c C3 win-spr spr seed mammal, wind short<br />
Bromus rigidus Rip Gut a c C3 win-spr spr seed mammal, wind short?<br />
Cenchrus ciliaris Buffel Grass p c C4 spr-aut opportunistic seed, short rhizome wind, mammal,<br />
water, bird<br />
Cenchrus echinatus Mossman River Grass a c C4 warmer<br />
months<br />
opportunistic seed wind, mammal mod<br />
Cortaderia selloana Pampas Grass p c C3 win-sum opportunistic seed, rhizome wind, water,<br />
slash, mammal<br />
Cynodon dactylon Couch p s/r C4 spr-aut sum seed, rhizome,<br />
stolon<br />
Cynosurus echinatus Rough Dog's Tail a c C3 sum seed<br />
water, ant, wind,<br />
slash,<br />
Dactylis glomerata Cocksfoot p c C3 variable spr-sum seed, tillers water, animal,<br />
slash,<br />
Digitaria ciliaris Summer Grass a c C4 spr-aut sum seed<br />
Digitaria sanguinalis Crab Grass a c C4 spr-aut sum seed<br />
Echinochloa crusgalli Barnyard Grass a c C4 spr-aut sum seed water, bird 1-9+<br />
Ehrharta brevifolia a c C3 spr seed<br />
Ehrharta calycina Perennial Veldgrass p c/sr C3 cooler<br />
months<br />
Ehrharta erecta Panic Veldgrass p c/sr C3 slows in hot<br />
conditions<br />
spr (2<br />
flushes)<br />
spr-sum<br />
(all year)<br />
seed, short rhizome water, wind, bird,<br />
mammal, slash<br />
seed, short rhizome water, wind, bird,<br />
slash<br />
Ehrharta longiflora Annual Veldgrass a c C3 yes aut-spr win-spr seed water, wind,<br />
mammal, slash<br />
3<br />
5+<br />
2<br />
3-4<br />
1-4+<br />
short-med<br />
short 1yr/long lived?<br />
Ehrharta villosa Pyp Gras p r C3 spr-sum spr-sum rhizome, seed? med-long?<br />
Eragrostis curvula African Lovegrass p c C4 warmer<br />
months<br />
opportunistic seed water, wind,<br />
mammal, slash<br />
Glyceria maxima Reed Sweet Grass p r C3 spr-aut sum seed, rhizome water med<br />
Hainardia cylindrica Common Barbgrass a c C3 win-spr spr-sum seed wind, water,<br />
mammal<br />
Holcus lanatus Yorkshire Fog p c C3 win-spr spr-sum seed wind, water,<br />
mammal<br />
Holcus setiger Annual Fog a c C3 yes aut-win spr seed mammal<br />
Hordeum glaucum,<br />
H. leporinum,<br />
H. marinum<br />
Northern Barley Grass,<br />
Barley Grass, Sea Barley<br />
Hyparrhenia hirta Tambookie Grass p c C4 warmer<br />
months<br />
a c C3 yes aut-win spr seed mammal 2<br />
sum erratic seeder,<br />
tiller<br />
Lifeform: a = annual, p = perennial. Growth form: c = caespitose, r = rhizomatous, s = stoloniferous, sr = shortly rhizomatous. Photosynthetic pathway: C3 =<br />
cool season grass, C4 = warm season grass. Growing season: usual period of active growth. Flowering: period over which grass flowers.<br />
Seedbank persistence: length of seed viability in years (where known).<br />
1+<br />
4+
Chapter 3 Grass <strong>Weeds</strong> Management Table<br />
Fire response Suggested methods of management and control References<br />
killed 17, 60, 167, 242<br />
resprouts Dig out very small infestations; spray with glyphosate 1 % + penetrant. 281, 256, 30, 167, 242<br />
resprouts Cut out plants, ensure rhizomes are removed; spray with grass-selective herbicide in winter/spring. Follow-up with seedling control. 231, 260, 241, 30, 167, 242<br />
resprouts Cut down close to ground and paint with neat glyphosate; carefully spot spray regrowth with 1 % glyphosate before 60 cm high (requires 4-6<br />
treatments) or Verdict 120 ® 10 mL/L + wetting agent or Fusilade ® 10 mL/L + wetting agent.<br />
162, 241, 316, 290, 300,<br />
126, 193, 222, 167, 242<br />
Spray at 3-5 leaf stage with Fusilade ® 10 mL/ 10 L (500 mL/ha) + wetting agent; repeat over following 2 years. 17, 316, 237, 60, 228, 222,<br />
167, 242<br />
Spray at 3-5 leaf stage with Fusilade ® 10 mL/ 10 L (500 mL/ha) + wetting agent; repeat over following 2 years. 17, 316, 237, 60, 228, 222,<br />
167, 242, 156<br />
fire rare in habitat<br />
but survives<br />
resprouts, stimulates<br />
seed production<br />
Spray when actively growing from spring to autumn with 8 mL/L (4 L/ha) Fusilade ® +wetting agent. 17, 316, 222, 167, 242<br />
Prevent seed set. Spray in winter 1 % glyphosate. 60, 222, 167, 242<br />
Prevent seed set - hand pull or spray at 3-5 leaf stage with Fusilade ® 10 mL/ 10 L (500 mL/ha) + wetting agent; repeat for 2 - 3 years. 231, 212, 30, 313, 228,<br />
222,167, 242<br />
Prevent seed set - hand pull or spray at 3-5 leaf stage with Fusilade® 10 mL/ 10 L (500 mL/ha) + wetting agent; repeat following year if required. 154, 300, 60, 228, 167, 242<br />
Prevent seed set - hand pull or spray at 3-5 leaf stage with Fusilade ® 5 mL/10 L (250 mL/ha) + wetting agent; repeat following year if required. 165, 60, 228, 167, 242<br />
Prevent seed set - hand pull or spray at 3-5 leaf stage with Fusilade ® 10 mL/ 10 L (500 mL/ha) + wetting agent; repeat following year if required. 154, 60, 167, 242<br />
Cut out small populations, entire plants with dormant buds must be removed; spray with Fusilade ® 600 mL/ha + wetting agent or spot spray with<br />
glyphosate 1 %. Follow-up with seedling control.<br />
241, 307, 33, 208, 300, 289,<br />
310, 101,167, 242<br />
Prevent seed set, spray with Verdict 520 ® 5 mL/10 L (250 mL/ha) + wetting agent or spot spray with glyphosate 1 %. Follow-up with seedling control. 241, 248, 95, 289, 101, 222,<br />
167, 242<br />
resprouts Cut out small plants, do not leave uprooted plants lying on ground - they can resprout; remove flower heads - slash/burn clumps and spray regrowth<br />
with 1 % glyphosate . Treat young plants with 0.5 % Fusilade ® plus spray oil. May require more than one application.<br />
resprouts Solarisation; shade out; spray Fusilade ® 5 mL/L + wetting agent in late spring/summer and then in autumn or glyphosate 1 %;<br />
follow-up always required. Particularly effective after fire.<br />
Spot spray 50g 2,2 DPA + wetter in 10 L of water. 222<br />
231, 21, 152, 134, 241, 300,<br />
30, 331, 228, 222,167, 242<br />
231, 307, 241, 59, 24, 289,<br />
53, 222, 101,167, 242<br />
resprouts, increases Cut out plants; slash/burn clumps and spray regrowth with glyphosate 1 %. Follow-up with seedling control over following years. 231, 30, 17, 241, 298,167,<br />
242<br />
Spray 0.5 % glyphosate in spring/summer or Verdict 520 ® 2 mL/10 L (100 mL/ha) + wetting agent. 241, 222, 247,167, 242<br />
Spray 1 % glyphosate in spring. 300,167, 242<br />
probably killed Prevent seed set; intolerant of dense shade; spray Verdict 520 ® 5 mL/10 L (250 mL/ha) + wetting agent at 3-5 leaf stage up to first tillering. 17, 118, 222,167, 242<br />
resprouts, enhances seed<br />
production and germination<br />
resprouts, enhances seed<br />
production and germination<br />
Spot spray 1 % glyphosate.<br />
Cut out - ensure crown removal; spray with Fusilade ® 8 mL/L (4L/ha) + wetting agent - follow-up in subsequent years; utilise unplanned fires and<br />
spray regrowth and seedlings within 4-6 weeks. Do not slash.<br />
231, 97b, 216, 102, 289, 68,<br />
167, 242<br />
Cut out small populations removing all rhizomes; spray with Fusilade ® ; utilise unplanned fires and spray regrowth and seedlings within 4-6 weeks. 231, 210, 167, 242<br />
Hand pull; spray with Fusilade ® 20 mL/10 L + wetting agent before flowering stem emerges; or 10 mL/ 10 L (500 mL/ha) at 3-5 leaf stage - secondary<br />
seedling flush often occurs - repeat if necessary.<br />
231, 30, 228, 222, 167, 242<br />
resprouts Spray with Verdict 520 ® 10 mL/ 10 L (500 mL/ha) or glyphosate 1 % + penetrant. 228, 222, 167<br />
resprouts Cut out small plants; spray with 1 % glyphosate; utilise unplanned fires and spray regrowth at 5-10 cm. Always requires follow-up treatment. 231, 345, 248, 92, 102, 228,<br />
167, 242<br />
resprouts Spray monocultures with 1 % glyphosate + Pulse® or Fusilade®<br />
(10 mL/L) + Agral (3.5 mL/L) towards end of summer, respray begining of<br />
following summer.<br />
240, 21, 96, 167, 242<br />
Spray glyphosate 0.5 % 17, 60, 30, 222, 167, 242,<br />
222<br />
Spray glyphosate 0.5 % 167, 242, 222<br />
Prevent seed set - hand pull or spray with Fusilade ® 10 mL/ 10 L (500 mL/ha) + wetting agent 4-6 weeks after opening rains . 228, 222, 167, 242<br />
resprouts Cut out small populations - ensure tiller bud removal; spray with 1 % glyphosate between November and March. Spray seedlings at 5 leaf stage with<br />
Fusilade ®<br />
at 20 mL/10 L (1L/ha) or slash in spring and spot spray regowth when 15cm high with glyphosate.<br />
167, 242<br />
247, 313, 209, 167, 242<br />
29
Chapter 3 Grass <strong>Weeds</strong> Management Table<br />
Lagurus ovatus Hare's Tail Grass a c C3 yes win-spr spr-sum seed mammal, wind 2-3<br />
Lolium rigidum Annual Ryegrass a c C3 win-spr spr-sum seed water, wind,<br />
mammal<br />
Lolium temulentum Darnel a c C3 win-spr spr-sum seed water, wind<br />
Melinis repens Natal Redtop p c C4 warmer<br />
months<br />
30<br />
Species Common name Lifeform Growth<br />
form<br />
sum seed<br />
Parapholis incurva Coast Barbgrass a c C3 aut-win spr seed<br />
Paspalum dilatatum Paspalum p c/sr C4 late spr-early<br />
aut<br />
sum seed, short rhizome animal, water,<br />
wind<br />
Paspalum distichum Water Couch p s/r C4 spr-aut sum stolon, rhizome,<br />
seed<br />
Paspalum urvillei Vasey Grass p c/sr C4 spr-aut spr-sum seed<br />
Paspalum vaginatum Saltwater Couch p s C4 spr-aut sum<br />
Pennisetum<br />
clandestinium<br />
Pennisetum<br />
macrourum<br />
Kikuyu p s/r C4 warmer<br />
months<br />
African Feather Grass p c/r C4 spr-aut sum seed, rhizomes,<br />
tillers<br />
Pennisetum purpureum Elephant Grass p c/r C4 spr-aut spr-sum rhizomes, tillers,<br />
seed?<br />
2-4<br />
water ?<br />
sum rhizomes, stolons water, wind seed rare<br />
water, wind<br />
Pennisetum setaceum Fountain Grass p c C4 spr-aut spr-sum seed wind,water,<br />
mammal, slash<br />
Pentaschistis airoides False Hair Grass a c C3 win spr seed<br />
Pentashchistis pallida Pussy Tail p c C3 win spr seed wind, ant<br />
Phalaris minor Lesser Canary Grass a c C3 win-spr spr-sum seed wind, water,<br />
mammal<br />
Phleum arenarium Phleum a c C3 win spr seed wind, water<br />
Phragmites australis Common Reed p r/s C3 spr-sum sum rhizomes, stolons,<br />
(seed)<br />
Piptatherum<br />
miliaceum<br />
Rice Millet p c C3 win-spr spr-sum seed mammal, wind,<br />
water<br />
wind, water, bird viable seed?<br />
6+<br />
wind, water establishment rare<br />
Poa annua Winter Grass a c C3 yes win-spr spr seed wind, water 3<br />
Polypogon maritimus Coast Beardgrass a c C3 win-spr spr-sum seed<br />
Polypogon<br />
monspeliensis<br />
Annual Beardgrass a c C3 win-spr spr-sum seed mammal, wind,<br />
water<br />
Rostraria cristata Annual Cat's Tail a c C3 win spr seed<br />
Rostraria pumilla Rough Cat's Tail p c C3 win spr<br />
Sorghum halepense Johnson Grass p r C4 spr-sum sum seed, rhizome explosive, wind,<br />
water, bird<br />
Spinifex sericeus Spinifex p s C4 spr-sum late<br />
spr-sum<br />
Sporobolus africanus Paramatta Grass p c C4 spr-sum late<br />
spr-sum<br />
Stenotaphrum<br />
secundatum<br />
Buffalo Grass p s C4 less active<br />
in winter<br />
stolon, seed?<br />
sum rhizomes, stolons,<br />
some seed<br />
Tribolium uniolae Tribolium p c/sr C3 spr spr-sum seed,<br />
short rhizome<br />
Urochloa mutica Para Grass p s C4 late<br />
spr-sum<br />
irregular stolon, (irregular<br />
seeder)<br />
seed wind, water,<br />
mammal<br />
5+<br />
water seed rare<br />
water, wind, ant ?<br />
wind, water (seed set variable)<br />
Vulpia bromoides Squirrel's Tail Fescue a c C3 win-spr spr mammal, water persistent (med?)<br />
Vulpia myuros Silver Grass, Rat's Tail<br />
Fescue<br />
Photosynthetic<br />
pathway<br />
Staggered<br />
germination<br />
Growing<br />
season<br />
Flowering Reproductive unit Dispersal agent Seedbank persistence<br />
(years)<br />
a c C3 win-spr spr seed mammal, water 2-3<br />
Lifeform: a = annual, p = perennial. Growth form: c = caespitose, r = rhizomatous, s = stoloniferous, sr = shortly rhizomatous. Photosynthetic pathway: C3 =<br />
cool season grass, C4 = warm season grass. Growing season: usual period of active growth. Flowering: period over which grass flowers.<br />
Seedbank persistence: length of seed viability in years (where known).
Chapter 3 Grass <strong>Weeds</strong> Management Table<br />
Fire response Suggested methods of management and control References<br />
Prevent seed set - spray with 10 mL/ 10 L (500 mL/ ha) Fusilade ®<br />
+ spray oil at 2-8 leaf stage before stem elongation. 60, 30, 228, 222, 167, 242<br />
Prevent seed set - hand pull or spray with grass-selective herbicide 4-6 weeks after opening rains. 60, 228, 167, 242<br />
Prevent seed set -spray with 10 mL/ 10 L (500 mL/ha) Fusilade ® + wetting agent before stem elongation. 60, 222, 167, 242<br />
Cut out small populations. Spray 8 mL/L (2-4L/ha) Fusilade ® + wetting agent. 60, 241, 101, 167, 242<br />
Cut out small populations - ensure rhizome removal; spray with grass selective herbicide or cut near ground level and immediately wipe with 10 %<br />
glyphosate or spray adult plants10 mL/L Fusilade + wetting agent. Follow-up seedling control - spray 1 mL/L Fusilade ® + wetting agent.<br />
231, 96, 247, 241, 222, 167,<br />
242<br />
resprouts Spray with glyphosate 1 %, 2-3 sprays over single growing season. Plant weed break to block spread into at risk habitats. 292, 228, 167, 242<br />
Cut out small populations - ensure rhizome removal; slash and spray regowth with grass-selective herbicide or 1 % glyphosate. Follow-up seedling<br />
control - spray 10 mL/L Fusilade ® + wetting agent.<br />
As for P. distichium<br />
resprouts Solarisation over warmer months; spray with 1 % glyphosate or Fusilade ® 10 mL/L + wetting agent, 2-3 sprays over single growing season<br />
often required.<br />
resprouts Dig out small infestations; slash winter and/or spray with glyphosate 1 % + penetrant in spring to autumn. Follow up treatment until regrowth ceases -<br />
follow-up seedling control.<br />
resprouts Dig out small infestations; slash winter and/or spray with glyphosate 1 % + penetrant in spring to autumn. Follow up treatment until regrowth ceases -<br />
follow-up seedling control.<br />
resprouts Dig out small infestations; slash winter and/or spray with glyphosate 1 % + penetrant in spring to autumn. Follow up treatment until regrowth ceases -<br />
follow-up seedling control.<br />
247, 167, 242<br />
231, 241, 21, 247, 53, 228,<br />
167, 242<br />
21, 96, 149, 248, 30, 122,<br />
167, 242, 150<br />
241, 167, 242<br />
314, 241, 26, 102, 53, 190,<br />
167, 242<br />
60, 167, 242<br />
Prevent seed set - cut out or spray with grass-selective herbicide. 60, 167, 242<br />
Prevent seed set - Spray 5 mL/L Fusilade ® + wetting agent. 60, 167, 242<br />
60, 167, 242<br />
resprouts In summer dry areas, slashing over succesive years reduces biomass; spot spray with glyphosate. 60, 167, 129, 242, 315<br />
Cut out young plants, slash larger clumps and spot spray with glyphosate. 60, 167, 242<br />
60, 167, 242<br />
Spot spray 1 % glyphosate. 167, 242, 222<br />
Spot spray 1 % glyphosate. 60, 167, 242, 222<br />
resprouts Spray during first 2 weeks of season's growth - glyphosate 1 % (during summer); or 8 mL/10 L (400 mL/ha) Verdict 520 ® + wetting agent; avoid soil<br />
disturbance; follow-up with spot sprays and seedling control.<br />
resprouts 167, 242<br />
167, 242<br />
167, 242<br />
167, 234, 53, 21, 16, 293,<br />
78, 53, 222, 242<br />
resprouts Cut and bag seed head then dig out; slash large clumps in winter/spring and spray regrowth with glyphosate at label ra tes (summer/autumn). 167, 300, 27, 242<br />
resprouts Solarisation over warmer months; spray with glyphosate 1 %, 2-3 sprays over single growing season or 8 mL/L (4 L/ha) Fusilade ® + wetting agent.<br />
Plant weed break to block spread into at risk habitats.<br />
resprouts Spot spray with glyphosate 10 mL/L or Fusilade ® 12 mL/L + wetting agent prior to boot stage. Spot spray resprouting clumps and blanket spray<br />
seedling flushes with Fusilade ® 10 mL/L + wetting agent.<br />
167, 231, 21, 228, 222, 242<br />
167, 43, 242<br />
resprouts Spray with 2 % glyphosate. 167,241, 300, 289, 242<br />
Prevent seed set - hand pull, spray with Select ® 10mL/ 10 L (500 mL/ha) (resistant to 'fops' group of herbicides) prior to boot stage. 228,167, 242<br />
seed survives most fires Prevent seed set - hand pull, spray with Select ® 10 mL/ 10 L (500 mL/ha) (resistant to 'fops' group of herbicides) prior to boot stage. 309, 228, 242<br />
31
32<br />
Chapter 4 Corms, Bulbs<br />
and Tubers<br />
The <strong>Weeds</strong> that Die Back to Fleshy Underground<br />
Storage Organs<br />
Dying back to underground storage organs is a strategy<br />
to avoid drought and fire and to cope with low-nutrient<br />
soils (Raunkaier 1934, Pate and Dixon 1982, Ruiters et<br />
al. 1993). This strategy is employed by plants of<br />
Mediterranean ecosystems across the world and these<br />
plants are known as geophytes. Around 95 % of<br />
geophytes introduced to south west Australia come<br />
from the Cape Region of South Africa. Pre-adapted to<br />
the Mediterranean climate, the nutrient-poor soils and<br />
relatively frequent fires of south west Western<br />
Australia, they pose a serious threat to bushland in the<br />
region. The ability to invade relatively undisturbed<br />
bushland makes them a particularly serious group of<br />
environmental weeds.<br />
Geophyte weeds can be found invading a range of plant<br />
communities and conservation reserves across the<br />
Swan Coastal Plain and Jarrah Forest. On the<br />
Spearwood dunes at Shenton <strong>Bushland</strong> Freesia (Freesia<br />
alba x leichtlinii), Yellow Soldier (Lachenalia reflexa),<br />
Watsonia (Watsonia meriana) and Pink Gladiolus<br />
(Gladiolus caryophyllaceus) are all serious invaders of<br />
relatively undisturbed Banksia woodland. On the<br />
heavier winter wet soils at Brixton Street Wetlands,<br />
Harlequin Flower (Sparaxis bulbifera) and a number of<br />
Watsonia species are widespread in the wetland and a<br />
serious threat to the diverse native herblands. Babiana<br />
(Babiana angustifolia), Hesperantha (Hesperantha<br />
falcata), One Leaf Cape Tulip (Moraea flaccida) and<br />
Black Flag (Ferraria crispa) are all present in small<br />
populations on the disturbed edges. At the foot of<br />
Darling Scarp, in the Talbot Road <strong>Bushland</strong>, Harlequin<br />
Flower, Freesia and Bulbil Watsonia (Watsonia meriana<br />
var. bulbillifera) are invading undisturbed Marri and<br />
Banksia woodlands, displacing the native herbs that<br />
make up much of the understorey. Just north of Perth<br />
along the edges of the Gingin Brook, Arum Lily<br />
(Zantedeschia aethiopica) and Taro (Colocasia<br />
esculenta) are a serious threat to the last remaining<br />
patches of Swamp Paperbark (Melaleuca rhaphiophylla)<br />
and Flooded Gum (Eucalyptus rudis) woodlands. Most of<br />
these bushlands are listed as regionally significant and<br />
some support rare and threatened flora and threatened<br />
plant communities. Geophyte weeds are one of the<br />
greatest threats to their conservation values.<br />
This chapter deals with the weedy geophytes as a<br />
group as they often share common life-cycles and<br />
similar reproductive biology. This in turn often relates<br />
to similar control methods and management strategies.<br />
A single plant of Watsonia meriana on the edge of shrublands in<br />
Talbot Road <strong>Bushland</strong>.<br />
In this chapter the life-cycles and reproductive biology<br />
of the corms, the bulbs and then the tubers are<br />
described. How this relates to their dispersal, spread,<br />
establishment and persistence over time is covered<br />
next. Towards the end of the chapter detailed case<br />
studies illustrate how all this information relates to<br />
management and how it can be used to control these<br />
weeds where they are invading particular bushlands.<br />
Finally a table of available control and management<br />
information for 57 species of geophyte weeds is<br />
presented.
The underground storage organs;<br />
life-cycles and reproduction<br />
The underground storage organs of these weeds fall<br />
into three categories; corms, bulbs or tubers –<br />
depending on the plant part that is modified to make<br />
up the storage organ. Understanding their life-cycles<br />
and reproductive biology is an important part of<br />
knowing how to prevent spread and control these<br />
sometimes indefatigable invaders.<br />
The corms<br />
Corms comprise underground swollen stems or stem<br />
bases. The following naturalised genera Babiana,<br />
Chasmanthe, Freesia, Gladiolus, Hesperantha, Watsonia,<br />
Moraea, Sparaxis and Ferraria all die back to corms<br />
over summer.<br />
Freesia forming stem cormels just after<br />
flowering in late spring/early summer.<br />
Chapter 4 Corms, Bulbs and Tubers<br />
Life-cycles<br />
Almost without exception the weedy cormous plants in<br />
south west Western Australia are summer-dormant<br />
sending up their first shoots as the temperatures drop<br />
with the autumn rains. Almost all have annually<br />
renewed corms (Du Plessis and Duncan 1989). That is,<br />
each year a new daughter corm, sometimes two, is<br />
formed as the plant is actively growing. Meanwhile the<br />
parent corm slowly exhausts and dies. Sometimes the<br />
remains of the parent can be observed as a series of<br />
plates below large old corms of Watsonia or woody<br />
tunics on corms of Hesperantha.<br />
Black Flag is an interesting exception. It has a column<br />
of persistent perennial corms to which a new corm is<br />
added each year (Box 4.1). Taro, a native of southeast<br />
Asia, is another exception. It grows actively through<br />
summer and has a perennial corm. Although dormant<br />
through winter it doesn’t always lose its leaves.<br />
Reproduction<br />
Basal cormels on Wavy Gladiolus<br />
(Gladiolus undulatus).<br />
Cormous weeds are able to reproduce vegetatively in a<br />
variety of ways.<br />
• Two or more daughter corms from the one parent<br />
corm.<br />
• Axilliary buds formed on parent corms that go to<br />
produce new plants when the growing shoot is<br />
removed.<br />
• Tiny ‘seed like’ cormels produced around the base<br />
of the parent corm or along stems.<br />
Most species also reproduce by seed and seed and<br />
cormels are the main mechanisms for medium to long<br />
distance dispersal.<br />
Stem cormels on Bulbil Watsonia in<br />
late spring, after flowering.<br />
33
34<br />
Chapter 4 Corms, Bulbs and Tubers<br />
The bulbs<br />
Bulbs are made up of swollen leaf bases. They form the<br />
underground storage organs for many common weeds<br />
such as Amaryllis, Allium, Lachenalia and Oxalis. The<br />
bulbs of Lachenalia, Oxalis and Allium are annually<br />
renewed while others such as Amaryllis are perennial.<br />
Life-cycles<br />
Most bulbous weeds are summer dormant, sending up<br />
leaves as the temperatures drop with the first autumn<br />
rains. Flowering and seed set take place at the end of<br />
the growing season, in winter to late spring. There are<br />
exceptions though. The flowers of Easter Lily<br />
(Amaryllis belladonna) and some others in the family<br />
Amaryllidaceae emerge in early autumn, often long<br />
before the first rains with the leaves appearing after<br />
flowering is finished.<br />
Bulbils forming on the<br />
base of Yellow Soldier<br />
stems.<br />
Reproduction<br />
Bulbous weeds reproduce vegetatively in a number<br />
of ways.<br />
Perennial bulbs such as Amaryllis and Narcissus<br />
produce offsets or daughter bulbs each year.<br />
Oxalis produces new bulbs and bulbils that arise from<br />
nodes along underground stems.<br />
Lachenalia bulbifera, as the name suggests, has a<br />
frightening capacity to reproduce from bulbils formed<br />
around the base of the bulb, along underground stems<br />
and even along the base of leaves left lying around.<br />
Lachenalia refexa (Yellow Soldier) has also been<br />
observed to produce bulbils on the base of leaves<br />
and flowering stems that have become separated from<br />
the bulb.<br />
Most bulbous weeds produce large amounts of seed<br />
each year and seed appears to be a major mechanism<br />
for dispersal into relatively undisturbed bushland.<br />
Bubils forming on the end<br />
of underground stems in<br />
Finger Leaf Oxalis<br />
(Oxalis glabra).<br />
Bulb offset forming in<br />
Narcissus.<br />
Bulbils forming along the stems of Lachenalia<br />
bulbifera at flowering time.
The tubers<br />
Tubers generally comprise swollen underground<br />
stems or roots. Asparagus (A. asparagoides - Bridal<br />
Creeper, A. declinatus - Bridal Veil, A. densiflorus -<br />
Asparagus Fern and A. scandens - Climbing<br />
Asparagus) arise from rhizomes (underground stems)<br />
supported by a dense tuberous root mat. Arum Lily<br />
arises from a large tuberous root sometimes referred<br />
to as a rhizomatous tuber.<br />
Life-cycles<br />
The species of Asparagus that occur as weeds in<br />
bushland around Perth are all dormant over the<br />
summer months with active growth triggered by falling<br />
temperatures and the first rains in autumn.<br />
Arum lily will retain green leaves year round if there is<br />
sufficient water available. On drier sites it goes into<br />
dormancy over summer.<br />
Perennial tuberous root mat of Bridal Creeper<br />
with a shoot coming from the rhizome.<br />
Chapter 4 Corms, Bulbs and Tubers<br />
Reproduction<br />
Vegetative reproduction in Bridal Creeper is via yearly<br />
expansion of rhizomes supported by a perennial<br />
tuberous root mat. The mat is usually five to ten<br />
centimetres below the soil surface and up to 10<br />
centimetres thick. The rhizomes have a series of shoot<br />
buds along their length and new shoots always arise<br />
from the rhizome, never directly from a tuber. This bud<br />
bank confers local persistence and an ability to<br />
withstand disturbance (Willis 2000).<br />
The perennial tubers of Arum Lily produce offsets<br />
throughout the growing season. Spread in this way is<br />
very localised, less than 30 centimetres per year<br />
(Moore 1997).<br />
Both Arum Lily and Bridal Creeper produce large<br />
amounts of viable seed each year.<br />
Arum Lily tuber with tiny daughter<br />
tubers starting to form.<br />
35
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Chapter 4 Corms, Bulbs and Tubers<br />
Spread into undisturbed bushland<br />
Most bulbous and cormous species originally establish<br />
at bushland sites via dumped garden rubbish or soil.<br />
Once established, production of daughter corms or<br />
bulbs, unless there is extensive soil movement, only<br />
allows for local expansion of existing populations. Seed<br />
provides the major mechanism for medium to long<br />
distance dispersal into undisturbed bushland.<br />
The seeds of species such as Freesia, Sparaxis and<br />
Lachenalia have no specialised adaptation for<br />
dispersal, relying mainly on water or soil movement.<br />
Gladiolus, and to a lesser degree Watsonia, with their<br />
winged seeds, can also rely on wind for medium to<br />
long distance dispersal (Goldblatt 1989, Goldblatt and<br />
Manning 1998). The widespread distribution of Pink<br />
Gladiolus throughout bushland around Perth is often a<br />
reflection of its predominantly wind dispersed seed.<br />
Fire appears to play a major role in the seedling<br />
establishment of many of these species, facilitating the<br />
expansion of populations into otherwise intact<br />
bushland (Box 4.2).<br />
For those species that do not set seed, movement into<br />
relatively undisturbed bushland is reliant on soil<br />
disturbance. Soursob (Oxalis pes-caprae), Finger Leaf<br />
(O. glabra) and Four O’Clock (O. purpurea) rarely set<br />
seed in the Perth area. Spread is almost entirely<br />
dependent on movement of bulbs or bulbils. Left<br />
undisturbed Soursob will only spread around ten<br />
centimetres per year (Parsons and Cuthbertson 2001).<br />
Consequently these weeds often occur on the<br />
degraded edges of bushland and, without soil<br />
disturbance, rarely spread into intact areas.<br />
The tiny cormels produced around the base of<br />
cormous species such as Wavy Gladiolus (Gladiolus<br />
undulatus) and around the base and in the leaf axils of<br />
Two Leaf Cape Tulip (Moraea miniata), also provide a<br />
mechanism for medium to long distance dispersal and<br />
for spread into undisturbed bushland. This can be via<br />
water, soil movement, birds and human activity.<br />
c<br />
a<br />
Scale x 2<br />
Scale x 5 Scale x 5<br />
Seeds of a) Watsonia, b) Pink Gladiolus, c) Freesia, d) Harlequin Flower, e) Yellow Soldier.<br />
Birds are the agents of medium to long distance<br />
dispersal of the fleshy berries of Arum Lily and the<br />
small red berries of Bridal Creeper and the major<br />
mechanism for establishment of new populations in<br />
undisturbed areas (Stansbury 1996, Moore 1997).<br />
Water flow and, for Arum Lily, foxes (ingesting seed),<br />
also play a role.<br />
Persistence of propagules<br />
The seeds<br />
Among natural populations within the Cape Region of<br />
South Africa, the seeds of most geophytes do not<br />
display dormancy and do not require fire-related cues<br />
(smoke or heat) to germinate (Keeley and Bond 1997).<br />
Interestingly horticulturists have found that with very<br />
few exceptions the seed of South African geophytes<br />
germinate easily, most in the first season after ripening<br />
(Du Plessis and Duncan 1989).<br />
The seed contained within the fleshy berries of Bridal<br />
Creeper generally germinate or decay within two years<br />
(Raymond 1996) and those of Arum Lily in less than six<br />
months (Panetta 1988).<br />
Observations in bushland around Perth certainly<br />
suggest that, for many species, most seed germinate in<br />
the first winter after ripening. Each year carpets of<br />
seedlings can be observed among invading populations<br />
of Freesia, Sparaxis, Lachenalia, Romulea and some<br />
species of Gladiolus. However in a season immediately<br />
following any control program where seed set is<br />
prevented, few seedlings can be observed. So once<br />
adult plants have been controlled follow-up work on<br />
seedlings could be over in a few short years. There are<br />
bound to be exceptions though.<br />
Effective management will rely on detailed<br />
information and research on individual species. In the<br />
meantime it is important to remain vigilant for at least<br />
five years following initial control of adult plants.<br />
d<br />
Scale x 1<br />
e<br />
b<br />
Scale x 5
Box 4.1 Black Flag – a growing concern<br />
Chapter 4 Corms, Bulbs and Tubers<br />
Black flag (Ferraria crispa) has been around as a garden escape in the Perth area for more than 100 years. It<br />
was first collected by the botanist Alexander Morrison from ‘east of Perth’ in 1898. It is now naturalised on<br />
sandier soils in Banksia and Tuart woodlands from Perth around the coast to Busselton, in Karri forest around<br />
Augusta and on sandier soils in Agonis woodlands near Albany. It has also been recorded from roadsides in the<br />
Wheatbelt, 100 km east of Perth, near Cunderdin (Western Australian Herbarium 1998).<br />
Currently Black Flag grows mainly in discrete patches on the disturbed edges of bushland and along roadsides.<br />
Spreading both by corms and seed, occasional infestations can be found in the middle of relatively undisturbed<br />
areas. Once established in bushland it can form dense monocultures excluding most native flora.<br />
The unusual biology of Black Flag makes it of particular concern to anyone trying to protect native plant<br />
communities from exotic invaders.<br />
Each year plants produce a new corm that is added to a column of dormant, previous years’ corms. In<br />
evolutionary terms the column is thought to be<br />
half way between a corm and a rhizome (Du Plessis<br />
and Duncan 1989).<br />
• Any herbicide application appears to knock<br />
only the present and sometimes the previous<br />
year’s corm, leaving all others intact.<br />
• The next corm down in the column generally<br />
sprouts the following year.<br />
• Herbicide does not appear to be translocated<br />
between corms in the columns.<br />
• If one of the dormant corms in the column is<br />
dislodged it will sprout and go on to produce a<br />
new plant.<br />
• Large amounts of seed are produced in late<br />
spring.<br />
Preventing Black Flag from becoming wide-spread<br />
in bushland in the short term is going to depend<br />
on careful physical removal of small infestations<br />
as soon as they become apparent, or, for large<br />
infestations, repeated herbicide application over<br />
many years. Research into the biology of Black<br />
Flag and management options are urgently<br />
required.<br />
For small infestations (approx 2 m x 2 m) on the<br />
disturbed edge of bushland think seriously about<br />
physical removal. But be warned – if extreme care<br />
is not taken your efforts could result in spreading<br />
Black Flag even further. You may need to sieve soil<br />
to get all corms and the level of soil disturbance will<br />
be extreme. All material will require very deep<br />
burial (more than a metre) away from your<br />
bushland site. Place excavated material in a ‘tough<br />
garden bag’ and send to the local tip for deep burial.<br />
The vegetative parts – corms, bulbs, tubers,<br />
offsets, cormels and bulbils.<br />
Vegetative material can sometimes have greater<br />
persistence in the soil than seed. The cormels of Two<br />
Leaf Cape Tulip are known to remain viable in the soil<br />
for at least eight years (Parsons and Cuthbertson 2001)<br />
and cormels from Bulbil Watsonia also remain viable<br />
for many years (Lamp and Collet 1989).<br />
Corm dormancy has been reported in Moraea,<br />
Gladiolus and Watsonia (Box 4.2). You may think you<br />
have the weed under control when in fact there is a<br />
population of dormant corms lying just beneath the<br />
soil surface waiting for the next fire or other suitable<br />
conditions to stimulate active growth.<br />
For many species that arise from corms or produce<br />
bulbils or cormels, follow-up work could be required<br />
for several years.<br />
37
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Chapter 4 Corms, Bulbs and Tubers<br />
Box 4.2 Fire and the geophyte weeds<br />
Fire is the major disturbance in the Mediterranean<br />
ecosystems of South Africa from where 95 % of our<br />
bulbous and cormous weeds have come. Consequently<br />
many have evolved life history traits that are strongly<br />
tied to recurrent fire.<br />
Mechanism for survival<br />
Dying back to an underground storage organ over the<br />
long dry summer is an extremely effective way of<br />
surviving fire. Soil offers very effective insulation to the<br />
corms or bulbs and some have contractile roots that<br />
pull the storage organs of young plants deeper into the<br />
soil helping avoid lethal fire temperatures (Bond and<br />
van Wilgen 1996). When dormant in summer, most<br />
cormous, bulbous and tuberous weeds will probably<br />
survive all but the very hottest fires.<br />
Dormancy and fire-stimulated flowering<br />
Some cormous and bulbous weeds, to varying degrees, are dormant between fires and sometimes between<br />
seasons. That is, the corms remain dormant in the soil producing no leaves or flowers during the growing<br />
season. Within Cape Tulip populations, for example, up to 60 % of corms may be dormant in any one season.<br />
Fire often brings most corms out of dormancy but seasonal conditions including soil temperature and rainfall<br />
also play a role (Parsons and Cuthbertson 2001).<br />
Others flower particularly well following fire with fire-stimulated flowering commonly observed among many<br />
geophytes where they occur naturally in southern Africa (Goldblatt 1978, Richardson et al. 1984, Le Maitre and<br />
Brown 1992). Nearly all species of Watsonia flower profusely following veld fire (Goldblatt 1989). Some, such as<br />
Watsonia borbonica, only flower for the first few seasons following fire (Le Maitre 1984). This mass flowering<br />
corresponds with prolific seed production. Displays of Gladiolus are also striking in the first few seasons<br />
following a burn, particularly in the winter rainfall areas on the nutrient-poor sandstone soils of the Cape<br />
Region (Goldblatt and Manning 1998). It is also interesting to note that horticulturists commonly use smoke to<br />
induce flowering in South African geophytes with Narcissus tazetta, Freesia and Crinum species all responding<br />
favourably (Tompsett 1985, Mathew 1997).<br />
Fire-stimulated flowering also appears to occur to some degree among populations of these plants where they<br />
are invading the Mediterranean ecosystems of southern Australia. Interestingly both corm dormancy and firestimulated<br />
flowering have been recorded in Pink Gladiolus invading Banksia woodland near Perth (Marshall<br />
2001). In the first season following fire workers recorded a mean of 42 flowering plants per one metre square<br />
plot. Two years after the fire a mean of only 2.6 flowering plants was recorded. The total number of plants<br />
(flowering and non-flowering combined) decreased from a mean of 54 per plot to 7 plants per plot. This work<br />
indicates that most corms of Pink Gladiolus seem to go into dormancy between fires. How wide-spread the<br />
phenomenon is among weedy geophytes requires further investigation as it has important implications for<br />
management and control of cormous and bulbous weeds.<br />
Seeds, seedlings and spread<br />
Generally the seeds of these plants do not require the smoke or heat of fire for germination. Rather, it is<br />
thought that the fire-stimulated flowering is actually linked to favourable post-fire conditions. For cormous and<br />
bulbous plants the post-fire environment offers space and light for seed germination and seedling<br />
establishment in the absence of larger trees and shrubs (Keeley and Bond 1997, Goldblatt and Manning 1998).<br />
With mass flowering and prolific seed production followed by favourable conditions for seed<br />
germination and seedling establishment, fire appears to be one of the major factors facilitating the<br />
establishment of many of these weeds into otherwise undisturbed bushland.<br />
A window of opportunity<br />
Pink Gladiolus flowering in the spring season following a summer<br />
fire in Banksia woodland at Shenton <strong>Bushland</strong>.<br />
Fire however also offers a significant opportunity to control bulbous, cormous and tuberous weeds in<br />
bushland. Following a summer fire these weeds will often emerge in autumn, prior to regeneration of native<br />
vegetation. The plants are clearly visible and the resprouting flowering bulbs, corms and resprouting tuberous<br />
mats of bridal creeper are an easy target for herbicide control. Control of established populations and<br />
prevention of seed production and further spread are achievable. It is an ideal time to control those species<br />
such as Cape Tulip and Pink Gladiolus that are largely dormant between fires.<br />
Additional resources should always be made available to control bulbous, cormous or tuberous weeds<br />
following fire.
Management and control<br />
Stopping the spread<br />
• Understand the distribution of the weed across the<br />
bushland by mapping the spread. This is an<br />
important first step (chapter 7). Maps are the<br />
basis for any strategy to limit further spread and<br />
contain existing populations.<br />
• Target small populations in good bush and the<br />
outliers of dense infestations (use the maps).<br />
• Determine if paths and water run-off are<br />
contributing to spread of cormels, bulbils or seed.<br />
• Determine whether the sources of infestations are<br />
old soil or rubble dumps. Sometimes the only<br />
option may be physical removal of these dumps<br />
(Box 4.3).<br />
• Avoid removing plant material at times of seed or<br />
cormel production.<br />
• Avoid working in areas where weeds are actively<br />
shedding seed.<br />
• Control in the season immediately following fire<br />
will prevent seed set in established plants, reduce<br />
seedling establishment in the post fire landscape<br />
and prevent expansion of existing populations.<br />
Chapter 4 Corms, Bulbs and Tubers<br />
Physical removal<br />
Although hand-removal can be very labour intensive<br />
and ties up a lot of resources it is often the most<br />
appropriate and sometimes the only method of control<br />
available. It is particularly appropriate for small<br />
isolated populations in good bushland.<br />
Targeting these isolated populations of weeds in<br />
good bushland and preventing their establishment<br />
and spread is the key to protecting undisturbed<br />
plant communities.<br />
Minimising soil disturbance<br />
Physically removing weeds with fleshy underground<br />
storage organs requires extreme care in handling. Soil<br />
disturbance can lead to the establishment of other<br />
weeds, particularly annual herbs (Hobbs and Atkins<br />
1988, Hobbs 1991). In Shenton <strong>Bushland</strong> the soil<br />
disturbance caused by physical removal of Yellow<br />
Soldier bulbs caused an increase in the cover of annual<br />
weeds such as Flat Weed (Hypochaeris glabra) and<br />
French Catchfly (Silene gallica). To try and minimise<br />
soil disturbance a range of tools are used for physically<br />
removing bulbous, cormous and tuberous weeds. Such<br />
tools include sharp knives, long screwdrivers and<br />
narrow trowels for smaller plants such as Freesia and<br />
Harlequin Flower and specially designed ‘Peter levers’<br />
for Watsonia and Arum Lily.<br />
Box 4.3 Dealing with sources of weed invasion into undisturbed bushland.<br />
Old rubble/garden refuse dumps throughout Shenton <strong>Bushland</strong> appear to be one of the major sources of<br />
cormous and bulbous weed invasion into undisturbed bushland. In late winter 2000 the Friends, City of Nedlands<br />
with a group of community service workers, Green Corps and EWAN, removed one such dump that appeared to<br />
be the source of Freesia invasion into the Banksia woodland at Shenton <strong>Bushland</strong>. The operation took five<br />
working days and involved moving around 30 cubic metres of rubble, taken away for deep burial at a tip site.<br />
The remaining bare ground was direct seeded with species of native herbs, shrubs and a few trees. The seed was<br />
collected from adjoining Banksia woodland. The following autumn Slender Podolepis (Podolepis gracilis), Prickly<br />
Moses (Acacia pulchella), Native Wisteria (Hardenbergia comptoniana) and Jarrah (Eucalyptus marginata) were<br />
among the species germinating on the removal site. A few annual weeds were also present.<br />
Green Corps team starting to remove the soil dump . The site on completion of removal.<br />
39
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Chapter 4 Corms, Bulbs and Tubers<br />
Timing is everything<br />
Understanding the life-cycle of the weedy geophytes<br />
over the growing season can mean the difference<br />
between effective control and unwitting spread. For<br />
many species hand-removal should only be carried out<br />
early in the growing season.<br />
• Late in the growing season specialised roots<br />
(known as contractile roots) drag annually<br />
renewed corms or bulbs deeper down into the soil.<br />
For the relevant species hand-removal is much<br />
easier and causes a lot less soil disturbance if<br />
undertaken early in the growing season e.g.<br />
Freesia, Sparaxis and Watsonia.<br />
• Stem cormels and bulbils are produced towards<br />
the end of the growing season. These are easily<br />
dislodged and can contribute to the spread of the<br />
weed you are trying to control e.g. Freesia,<br />
Sparaxis bulbifera, Lachenalia bulbifera.<br />
• Oxalis species produce bulbils at the nodes of<br />
underground stems later in the season, just after<br />
flowering. These are easily dislodged and handremoval,<br />
after bulbil formation has occurred,<br />
will generally contribute to their spread e.g.<br />
Soursob, Finger Leaf Oxalis and Four O’Clock.<br />
• Towards the end of the growing season, as the<br />
days get longer and warmer, many species finish<br />
flowering and start producing seed (often<br />
coincides with bulbil and cormel production).<br />
When physically removing plants that are setting<br />
seed ensure seed is not dislodged and spread<br />
through the bushland as material is transported.<br />
For the following species physical removal is<br />
hazardous at any time.<br />
• Those species that produce masses of cormels<br />
around the base are extremely difficult to<br />
physically remove without dislodging and<br />
spreading cormels any time of the year. The<br />
cormels are tiny, float in water and easily stick<br />
with mud to boots, tools and the feet of animals.<br />
Physical removal needs to be undertaken<br />
in a way that avoids releasing or dropping<br />
cormels. e.g. Wavy Gladiolus, Long Tubed<br />
Painted Lady (Gladiolus angustus) and<br />
Two Leaf Cape Tulip. The parent<br />
corm often confers dormancy on<br />
cormels and its removal is often<br />
followed by mass germination<br />
of those cormels left behind.<br />
• Arum Lily produces numerous tiny daughter<br />
tubers that become dislodged during handremoval.<br />
This appears to happen throughout the<br />
growing season.<br />
• The rhizomes attached to the tubers of Bridal<br />
Creeper will produce new shoots from any tiny<br />
fragments left behind.<br />
Note: Physical removal of weeds such as Watsonia, Arum Lily or<br />
Bridal Creeper on steeper slopes or along creeks and riverbanks can<br />
lead to serious soil erosion.<br />
fruits containing<br />
seed<br />
stem cormels<br />
a b c d<br />
Harlequin flower (Sparaxis bulbifera); a) Summer, dormant corm b) Late autumn, corm begins to sprout c) Early spring, flowering and corm<br />
exhaustion d) Spring to early summer, leaves begin to die back, seed and stem cormels are formed.
Slashing leaves and stems<br />
Repeated removal of leaves and stems of some species<br />
of weedy geophytes over time can reduce population<br />
density, reproductive output and plant vigour. It is<br />
generally labour intensive, however, and often not<br />
effective in the longer term. The few examples below<br />
illustrate where it can be a useful tool, under certain<br />
circumstances.<br />
• If Bridal Creeper is slashed back to the stem bases<br />
every month over the growing season for several<br />
years plants are severely weakened (J. Moore<br />
pers. comm.). In bushland on Garden Island, just<br />
off the coast of Perth, continual grazing by<br />
Tammar wallabies has prevented Bridal Creeper<br />
from becoming wide-spread on the island<br />
(Keighery 1993).<br />
• Trials in the fringing vegetation along Bennett<br />
Brook in Perth suggested that slashing Arum Lily<br />
back to the base every month over the growing<br />
season can, in the short term at least, greatly<br />
reduce the number of adult plants in a population.<br />
Plants were slashed to the base every month for<br />
seven months over the 1999 growing season. Over<br />
80 % of plants in the population did not resprout in<br />
the 2000 season (Brown unpubl). The slashing was<br />
done by hand with a sharp hoe and would be very<br />
labour intensive over a broad area. The work<br />
would need to continue over a number of years<br />
and if left for any length of time populations would<br />
probably quickly return to pre-treatment levels.<br />
• Work in South Australia has found if Bulbil<br />
Watsonia plants are slashed at 15 centimetres or<br />
less above the ground, at the first sign of a flower<br />
spike, neither flower spike nor bulbils will be<br />
produced in that year. In addition the plant will<br />
form smaller corms the following year (Wilson and<br />
Conran 1993).<br />
Note: simply removing flower spikes to prevent seed set can<br />
sometimes lead to more vigorous plants the following year. Work on<br />
Pink Gladiolus in south west Western Australia found that removal of<br />
flowers just as they were opening resulted in a larger replacement<br />
corm (and presumably more vigorous plants that would be harder to<br />
kill) the following year (Hocking 1992).<br />
Chemical control methods<br />
Chemical control of bulbous, cormous and tuberous<br />
weeds is often the only practical option available for<br />
dense infestations invading good bushland. It can be<br />
practical on a large scale, avoids soil disturbance and<br />
prevents soil erosion.<br />
Herbicide application needs to be done by experienced<br />
operators with the correct equipment, knowledge of<br />
herbicides and an understanding of bushland and of<br />
the native flora. Regardless of the herbicide,<br />
application needs to be carefully timed to be effective<br />
on many of the species dealt with in this chapter,<br />
particularly the annually renewed bulbs and corms<br />
(Box 4.4).<br />
Note: Anyone applying herbicides should have appropriate training<br />
in the safe use and handling of relevant chemicals (Chapter 8).<br />
Chapter 4 Corms, Bulbs and Tubers<br />
The herbicides<br />
Important note: The following herbicides are currently the subject<br />
of a minor use off-label permit in non-crop situations in Western<br />
Australia. Application must comply with all conditions of the permit.<br />
Available from: (http://permits.nra.gov.au/PER4984.PDF).<br />
Glyphosate<br />
When applied at the correct stage of the life-cycle, this<br />
non-selective herbicide has been found to be effective<br />
against a number of South African bulbous, cormous<br />
and tuberous species. These include Freesia (Freesia<br />
alba x leichtlinii), Ixia species (Dixon and Keighery<br />
1995), Watsonia (Day 1993) and Bridal Creeper<br />
(Pritchard 2002). Glyphosate is an acceptable option<br />
where the weeds occur in dense monocultures on the<br />
disturbed edges of bushland. However these weeds<br />
often grow closely amongst native vegetation and the<br />
use of non-selective herbicides can lead to<br />
unacceptable off-target damage unless the application<br />
method is very carefully targeted (Box 4.2 and Box 4.3).<br />
Metsulfuron methyl<br />
Following the introduction of the sulfonylurea group of<br />
herbicides in early 1980s, metsulfuron methyl (Brushoff<br />
® , Ally ® ) in particular has been found to be very<br />
effective against a number of South African<br />
bulbous/cormous species. These include Soursob<br />
(Peirce 1998), Bridal Creeper (Pritchard 1991, Dixon<br />
1996), Freesia (Dixon 1998b), Harlequin Flower (Meney<br />
1999, Brown and Brooks in press c) and Yellow Soldier<br />
(Brown et al. 2002). Interestingly, some of these studies<br />
suggest that many native species are resistant to the<br />
effects of metsulfuron methyl at rates of 5 g/ha and<br />
below (Dixon 1996, Meney 1999, Moore 1999, Brown et<br />
al. 2002, Brown and Brooks in press c). This is an area<br />
that requires further study and any use of the<br />
sulfonylurea group of herbicides in bushland needs<br />
very careful consideration. Metsulfuron methyl can<br />
remain active in dry alkaline soils and is absorbed by<br />
roots for many months following application (Parsons<br />
1995, Noy 1996, Sarmah et al. 1998).<br />
Chlorsulfuron<br />
Also of the sulfonylurea group of herbicides,<br />
chlorsulfuron (Glean ® ) is known to be effective on<br />
Arum Lily (Moore and Hoskins 1997), Cape Tulip<br />
(Parsons and Cuthbertson 2001) and Harlequin Flower<br />
(Brown and Brooks 2002). The impacts of chlorsulfuron<br />
on native plants that co-occur with these weeds are<br />
not well understood. Trials on Harlequin Flower<br />
invading herb-rich shrublands in the Brixton Street<br />
Wetlands indicated chlorsulfuron had an impact on<br />
some native herbs (Brown and Brooks in press c).<br />
Important note: Both metsulfuron methyl and chlorsulfuron can<br />
inflict damage to vegetation at very low concentrations. Both can<br />
remain active in the soil for some months following application. They<br />
should only be spot sprayed on target species invading native<br />
bushland and always by well-qualified responsible operators with a<br />
thorough knowledge of the native flora.<br />
2,2-DPA<br />
Reported to successfully control Watsonia invading<br />
remnant native vegetation. Sprayed at a rate of 10 g/L,<br />
2,2-DPA has little impact on a range of native species<br />
(Moore and Fletcher 1994, Brown and Brooks unpubl.).<br />
41
42<br />
Chapter 4 Corms, Bulbs and Tubers<br />
Targeted application techniques<br />
Sometimes the only option for effective control is a<br />
non-specific herbicide such as glyphosate. The<br />
herbicide needs to be carefully targeted so that only<br />
the weed, often growing closely amongst native<br />
vegetation, is treated. An example of a successful<br />
targeted application technique in practice is the<br />
effective control of Watsonia invading native bushland<br />
on the Darling Scarp (Day 1993). Using a 500 mL spray<br />
bottle with a sponge wired over the nozzle, a 10 %<br />
solution of glyphosate is wiped onto individual leaves<br />
just before flowering, at corm exhaustion. Community<br />
volunteers have controlled large populations of Watsonia<br />
and contained the spread of the weed using this method.<br />
The effectiveness of this treatment was recorded at<br />
three bushland sites<br />
across the Swan<br />
Coastal Plain from<br />
1999-2001 with some<br />
interesting results<br />
(case study 4.2).<br />
Wiping Watsonia leaves in spring in<br />
Shenton <strong>Bushland</strong>.<br />
Biological control<br />
For the smaller<br />
cormous and bulbous<br />
species wiping leaves<br />
of individual plants is<br />
not practical. In<br />
Shenton <strong>Bushland</strong> for<br />
example there were<br />
up to 1700 bulbs of<br />
Yellow Soldier in a<br />
single 2 m x 2 m plot.<br />
With limited resources<br />
available wiping<br />
individual plants was<br />
not an option (case<br />
study 4.1).<br />
Biological control is presently available for Bridal<br />
Creeper. In 1999 CSIRO released a leafhopper that<br />
weakens the plant by sucking sap, causing a silver<br />
patterning on leaves and reducing seed set. It is a very<br />
useful tool for preventing the spread of large<br />
infestations that are either inaccessible or beyond the<br />
resources of current control programs. A rust fungus<br />
has been released and is also available for the control<br />
of Bridal Creeper. Infected plants shed leaves early and<br />
are severely weakened. The rust is slow to spread<br />
through established populations of Bridal Creeper.<br />
Recording effectiveness of control methods<br />
and regeneration of native plant communities<br />
It is important to have in place objective methods for<br />
assessing effectiveness of control methods over time<br />
so treatments and management strategies can be<br />
adjusted accordingly.<br />
• Maps of a particular weed species in a patch<br />
of bush: These provide good base line<br />
information for a control program, and over time,<br />
if updated, will provide a record of the<br />
effectiveness of that program.<br />
• Fixed photo points: Although an interesting<br />
record, fixed photo points do not provide<br />
quantitative information on the overall success of<br />
the program or the degree of follow-up required.<br />
They also provide very limited information on the<br />
impact of a control program on the native plant<br />
community. As long as the limitations are<br />
recognised, photo points can be a useful tool for<br />
recording change over time. Photos were<br />
particularly useful for recording the highly visable<br />
changes that occurred following removal of Taro<br />
along the Gingin Brook, (case study 4.3), and for<br />
recording the change in Watsonia treatment sites,<br />
as long as they were accompanied by a detailed<br />
species list. They were not so useful for recording<br />
change following the removal of smaller cormous<br />
weeds such as Harlequin Flower in the diverse<br />
plant communities at Brixton Street.<br />
For more information Elzinga et al. (2001) provides<br />
very detailed information on setting up photo point<br />
monitoring and studies where repeat photography has<br />
been used to monitor long-term change.<br />
Importantly though, distribution maps and photos will<br />
not record in any detail changes in weed populations.<br />
Recording the density and frequency of particular<br />
weeds from year to year is often vital in assessing the<br />
effectiveness of a control program. Also, when<br />
undertaking any weed management program in<br />
bushland, the focus is not simply on eliminating weeds<br />
but on protection of intact native plant communities. It<br />
is important to have an understanding of what impacts<br />
the control work is having and what moves in once the<br />
target weed/s have been controlled. In the incredibly<br />
diverse flora of south west Western Australia this can<br />
be a complex task. At one site on the eastern side of<br />
the Swan Coastal Plain there are over 300 native plant<br />
species in only 19 hectares and up to 80 in a 10 m x 10<br />
m plot. It is important to know and understand these<br />
systems if they are to be managed effectively for nature<br />
conservation. Some methods used to collect<br />
information on change over time in populations of<br />
weeds that die down to underground storage organs<br />
and co-occurring native species are described in case<br />
studies on Yellow Soldier (case study 4.1), Watsonia<br />
(case study 4.2), Taro (case study 4.3) and Harlequin<br />
Flower (case study 4.4).<br />
Note: With bulbous, cormous and tuberous weeds, until they begin<br />
active growth in the growing season following herbicide application,<br />
it is often not possible to know how many plants including the<br />
storage organ, have been killed. It may be nine months after<br />
treatment before you can assess effectiveness of a control program.<br />
Key points<br />
• South African geophytes are one of the most<br />
serious groups of bushland weeds in south west<br />
Western Australia.<br />
• Once established on disturbed edges they can<br />
invade relatively undisturbed bushland, generally<br />
via seed or cormels, form dense monocultures and<br />
displace native plant communities.<br />
• Fire appears to facilitate establishment of<br />
seedlings and expansion of populations.
• Fire also offers a valuable window of opportunity<br />
for control.<br />
• Understanding the life-cycles of these weeds is an<br />
integral part of effective chemical and physical<br />
control and preventing spread into intact<br />
bushland.<br />
Dealing with weedy geophytes invading bushland can<br />
be a complex task. The information in the following<br />
case studies illustrates that with a consistent and<br />
carefully targeted effort over time, effective control and<br />
containment of populations can be achieved. The case<br />
Box 4.4 Timing herbicide treatment<br />
Annually renewed corms and bulbs<br />
Chapter 4 Corms, Bulbs and Tubers<br />
For those species with annually renewed corms and bulbs, the<br />
most effective time for herbicide application is when the parent<br />
corm or bulb has shrivelled and the new daughter corm/bulb has<br />
only partly developed. This usually occurs just before or just at<br />
flowering. Apply the herbicide too early and the parent corm/bulb<br />
could have enough reserves to survive; too late and the daughter<br />
corm/bulb will not be affected.<br />
In addition herbicide application at this time prevents the<br />
development of bulbils in many species. This is particularly<br />
important with Oxalis pes-caprae, O. glabra and O. purpurea where<br />
new bulbils are formed on the nodes of underground stems each<br />
year (Du Plessis and Duncan 1989, Peirce 1990, 1998). If herbicide<br />
application takes place after bulbils have begun to develop they<br />
will probably survive and go on to produce new plants the<br />
following season.<br />
Perennial corms<br />
studies cover managing and controlling the spread of<br />
the Yellow Soldier, two species of Watsonia, Harlequin<br />
Flower and Taro where they are invading wetlands and<br />
woodlands around Perth. The final table provides<br />
detailed, species-specific information on control<br />
techniques where they are known. The information in<br />
the table also highlights the many species of weedy<br />
geophytes that have similar life-cycles and reproductive<br />
biologies. The next chapter looks at a much more<br />
diverse group of weeds, the broadleaf herbs that are<br />
not geophytes and the sedges and the succulents.<br />
Only two species dealt with here arise from perennial corms, Black<br />
Flag (Ferraria crispa) and Taro (Colocasia esculenta). Timing for<br />
control of Black Flag is quite problematic as the parent corm does not shrivel and die as the new corm<br />
develops, so effectively there is no corm exhaustion. In addition there is a series of previous years’ corms<br />
below the parent which appear to be joined by a fine thread of living tissue and it is not known if herbicides<br />
can be translocated between these corms (Box 4.1)<br />
Effective control of Taro was obtained by cutting and painting the bases in early to mid summer with<br />
glyphosate and spraying regrowth in late summer with glyphosate and metsulfuron methyl (Case Study 4.3).<br />
Some workers have noted that excessive sap movement when cutting bases early in the season prevents cut<br />
stumps from taking up herbicide.<br />
Perennial bulbs<br />
The lowest dry weight of a perennial bulb generally occurs just when all the leaves are up but before flowering<br />
(Dafni et al.1981). This is probably the time plants would be most vulnerable to herbicide application. An<br />
interesting exception is the Easter Lily (Amaryllis belladonna) which belongs to a group of bulbs that flower as<br />
temperatures drop with the first rains – before the leaves come up. Dry weight in the perennial bulbs with this<br />
kind of life-cycle is generally lowest as the new leaves emerge, a couple of months after flowering (Dafni et al.<br />
1981) and this is probably the best time to apply herbicide.<br />
Perennial tubers<br />
developing daughter<br />
corm<br />
exhausted<br />
parent corm<br />
remains of<br />
previous years’<br />
corms<br />
Corm exhaustion in Watsonia meriana – late winter.<br />
Herbicide application to Arum Lily is effective throughout its period of active growth (Moore and Hoskins 1997,<br />
Brown unpublished data). Early herbicide application prevents the majority of the population flowering and<br />
setting seed but misses tubers that begin active growth later in the season.<br />
Studies on Bridal Creeper (Asparagus asparagoides) have shown herbicide application to have an impact from<br />
flowering through to the green berry stage, although is most effective at flowering (Pritchard 2002).<br />
43
44<br />
Chapter 4 Corms, Bulbs and Tubers Case Studies<br />
Case study 4.1 Managing the spread of Yellow Soldier (Lachenalia reflexa)<br />
in a Banksia woodland<br />
Yellow Soldier (Lachenalia reflexa).<br />
This study investigated the<br />
effectiveness of hand-removal and<br />
two herbicide treatments on the<br />
control of Yellow Soldier<br />
(Lachenalia reflexa). Trials took<br />
place in the species-rich<br />
Banksia/Jarrah woodland in<br />
Shenton <strong>Bushland</strong>. The impact of<br />
each treatment on the native flora<br />
was also recorded.<br />
Carefully hand-removing Yellow Soldier in<br />
Shenton <strong>Bushland</strong>.<br />
Measuring cover of all species<br />
in treatment plots<br />
The ‘point quadrat’ method<br />
(Bonham 1989) was used to<br />
determine percentage-overlapping<br />
cover (referred to as cover) for all<br />
species using 200 points within<br />
each plot (2 m x 2 m). There were<br />
five replicates of each treatment.<br />
Effectiveness of treatments<br />
Hand-removal (1998 & 1999) over<br />
two seasons left all natives intact<br />
but was very labour intensive,<br />
reducing cover of Yellow Soldier by<br />
only 44 %. It also triggered<br />
germination of annual weeds.<br />
Wiping the leaves (1998) of<br />
individual plants with a 10 %<br />
glyphosate solution was not<br />
effective and was also very labour<br />
intensive.<br />
Spot spraying (1999) with<br />
metsulfuron methyl at 0.2 g/15 L (5<br />
g/ha) reduced the cover of Yellow<br />
Soldier by 65 % in one season and<br />
appeared to have no significant<br />
impact on native shrubs or herbs<br />
including native geophytes.<br />
The control (do nothing) Yellow<br />
Soldier increased in cover by over<br />
30 % between 1998 and 2000.<br />
Percentage cover<br />
55<br />
50<br />
45<br />
40<br />
35<br />
30<br />
25<br />
20<br />
15<br />
10<br />
5<br />
control<br />
hand removal<br />
herbicide<br />
1998 1999 2000<br />
Year<br />
Figure 1. Cover of Yellow Soldier in control,<br />
hand-removal and herbicide treatment plots<br />
in 1998,1999 and 2000. The bars indicate<br />
standard errors.<br />
Impacts on natives<br />
The herbicide treatments did not<br />
significantly affect native shrubs or<br />
perennial herbs, with both groups<br />
increasing in cover in the treatment<br />
plots over two years. Although the<br />
impacts of the metsulfuron<br />
treatment on native geophytes<br />
appeared not to be significant it was<br />
difficult to assess. There was a large<br />
variation across the trial sites in<br />
both cover (which is naturally low),<br />
and in species. Of the eight species<br />
present only one, Milkmaid<br />
(Burchardia congesta), was present<br />
in all 15 plots. Leafy Sundew<br />
(Drosera stolonifera), Vanilla Lily<br />
(Sowerbaea laxiflora), Climbing<br />
Fringe Lily (Thysanotus<br />
manglesianus), and Haemodorum<br />
spp. were present in most plots<br />
with Pale Grass Lily (Caesia<br />
micrantha) and Red Beak Orchid<br />
(Pyrorchis nigricans) occurring only<br />
occasionally.<br />
Percentage cover<br />
15<br />
10<br />
5<br />
0<br />
control<br />
hand removal<br />
herbicide<br />
1998 1999 2000<br />
Year<br />
Figure 2. Cover of native geophytes in<br />
control, hand-removal and herbicide<br />
treatment plots in 1998, 1999 and 2000.<br />
The bars indicate standard errors.<br />
Implications for management<br />
Yellow Soldier still comprised 12 %<br />
of cover in 2000 therefore indicating<br />
that any broad scale application<br />
would need to be carefully followed<br />
up for a number of years following<br />
initial application to ensure reinvasion<br />
does not occur.<br />
In the species-rich Banksia<br />
woodland at Shenton <strong>Bushland</strong>,<br />
Yellow Soldier co-occurs with up to<br />
25 native species in a 2 m x 2 m plot
Chapter 4 Corms, Bulbs and Tubers Case Studies<br />
and the current policy is to allow<br />
indigenous species to recolonise<br />
treated sites unassisted.<br />
One of the major weeds that<br />
invades sites where bulbous weed<br />
control has taken place on the<br />
sandy soils of the Swan Coastal<br />
Plain is Perennial Veldgrass<br />
(Ehrharta calycina). A spray<br />
program using Fusilade ® is<br />
successfully controlling this weed<br />
over much of Shenton <strong>Bushland</strong><br />
including the study site.<br />
Stopping the spread<br />
The distribution of Yellow Soldier in<br />
Shenton <strong>Bushland</strong> is not dependent<br />
on disturbance, with populations<br />
extending into relatively intact<br />
bushland (Figure 1, Chapter 2).<br />
Preventing spread into undisturbed<br />
areas is the primary aim of the<br />
control program.<br />
Yellow Soldier spreads within the<br />
bushland via seed. The populations<br />
are generally quite discrete<br />
suggesting seed is not easily<br />
dispersed over long distances.<br />
Table 1. Costing of Yellow Soldier control over time.<br />
Source: Brown et al. (2002).<br />
Water movement and human<br />
activity play a role in the spread.<br />
Fire reduces competition from the<br />
native vegetation and creates bare<br />
areas where the seed can<br />
germinate.<br />
Fire, however, can also create<br />
opportunities for land managers to<br />
prevent further spread and<br />
establishment. After fire, Yellow<br />
Soldier plants are clearly visible and<br />
the reduced cover of native<br />
vegetation makes the resprouting<br />
flowering bulbs an easy target for<br />
herbicide control.<br />
Understanding the current<br />
distribution of the weed allows any<br />
new infestations to be recognised,<br />
recorded and targeted for control.<br />
Note: In this trial, the metsulfuron methyl<br />
was, where possible, targeted at Yellow<br />
Soldier and not applied as a blanket<br />
treatment over all vegetation. This is not a<br />
difficult or time consuming task but does<br />
require responsible operators with a<br />
reasonable knowledge of the flora. There is<br />
evidence from other studies that some native<br />
species, particularly seedlings, are<br />
susceptible to metsulfuron methyl at 5 g/ha<br />
(Moore 1999).<br />
How the study was used<br />
In the two years since the results of<br />
the study became available to the<br />
Friends of Shenton <strong>Bushland</strong>, they<br />
have secured funding to implement<br />
control of Yellow Soldier across the<br />
bushland. The map helped provide<br />
information for costing the project<br />
and indicated clear objectives to<br />
funding bodies. The Friends have<br />
since hired an experienced<br />
contractor with knowledge of the<br />
flora who has carried out the work.<br />
With approximately one hectare of<br />
bushland currently invaded the cost<br />
of control is relatively low. In the<br />
first year funding was obtained<br />
through a state government grant<br />
and in the second year the local<br />
government authority agreed to<br />
fund the follow-up work and should<br />
continue to do so until the<br />
populations require only occasional<br />
hand-removal.<br />
YEAR TREATMENT COST/HECTARE AREA COST<br />
2001 Brush-off @ 2.5 - 5 g/hectare + pulse@2 mL/L. $300.00/hectare ~ 1 hectare (from maps) $300.00<br />
2002 Brush-off @ 2.5 - 5 m/hectare + pulse@2 mL/L. $300.00/hectare check 1 hectare $300.00<br />
2003 As above but also consider hand weeding isolated plants. $300.00/hectare check 1 hectare $300.00?<br />
2004 Now only hand weeding isolated plants may be required. check 1 hectare<br />
45
46<br />
Chapter 4 Corms, Bulbs and Tubers Case Studies<br />
Case study 4.2 Monitoring and managing Watsonia (Watsonia meriana and Watsonia<br />
meriana var. bulbillifera) invading wetlands and woodlands across the Swan Coastal Plain<br />
Transect running through Bulbil Watsonia population in Brixton Street Wetlands in a) August<br />
1999 and b) August 2001.<br />
While working on Watsonia<br />
populations at three different sites<br />
across the Swan Coastal Plain, the<br />
importance of monitoring the<br />
effectiveness of weed management<br />
work and of having an<br />
understanding of the biology of the<br />
target species became apparent. At<br />
all sites W. meriana and/or<br />
W. meriana var. bulbillifera formed<br />
dense monocultures, appearing to<br />
displace much of the herbaceous<br />
flora and seriously impact on native<br />
plant diversity.<br />
Mapping, monitoring and<br />
managing the populations<br />
In 1998 the populations of Watsonia<br />
at Shenton <strong>Bushland</strong>, Brixton Street<br />
Wetlands and Talbot Road <strong>Bushland</strong><br />
were mapped. Between July and<br />
September 1999 a transect was run<br />
through the length of each<br />
population, from the highly<br />
disturbed edge, through the<br />
Watsonia and into intact bushland. A<br />
series of quadrats (1 m x 1 m) were<br />
placed at regular intervals along the<br />
Table 1. Management actions and herbicide treatment over the monitoring period.<br />
1999<br />
2000<br />
2001<br />
SHENTON BUSHLAND<br />
Green Corps team and Friends wiped<br />
entire population with 1:10 glyphosate<br />
over 2 days in early September.<br />
Green Corps team again employed to do<br />
follow- up wiping. One day’s work.<br />
Green Corps team employed to do<br />
follow-up on the remaining smaller plants.<br />
One day.<br />
a b<br />
BRIXTON ST<br />
Friends and volunteers physically<br />
removed plants from the clay flats<br />
throughout the season and in early<br />
September wiped all plants in the<br />
population.<br />
Friends continued hand-removal and in<br />
early September Green Corps team<br />
assisted wiping the population.<br />
Plants left now quite numerous but too<br />
small for wiping individually and so<br />
Friends carry on hand-removal program.<br />
transects, the number of Watsonia in<br />
each quadrat counted, all other<br />
species occurring in each quadrat<br />
recorded and each quadrat<br />
photographed. This procedure was<br />
repeated in 2000 and again in 2001.<br />
Treatments at each site varied as<br />
outlined in Table 1.<br />
Shenton <strong>Bushland</strong><br />
Introduction and spread The<br />
bushland has a long history of<br />
having garden rubbish dumped<br />
along its boundaries. Alternatively,<br />
plant material may have been<br />
brought in with laterite gravel in<br />
World War II. Spread appears to be<br />
by slow expansion of the main<br />
population via corms and seed.<br />
Distribution Watsonia meriana<br />
occurs in a relatively small discrete<br />
population in Banksia–Jarrah<br />
woodland at the southern end of<br />
the bushland.<br />
Response to treatment Two years<br />
after treatment a relatively high<br />
number of plants remained in the<br />
plots (Figure 1) indicating that<br />
intensive follow-up will be required<br />
for a number of years. Before<br />
treatment the W. meriana<br />
population consisted mostly of<br />
large adult plants. One year after<br />
treatment the population consisted<br />
mostly of small single leafed plants,<br />
less than 10 cm high. Those smaller<br />
plants arose from corms and were<br />
not seedlings.<br />
TALBOT RD<br />
Contractor employed to spray dense<br />
infestations on disturbed edge and wipe<br />
plants growing closely among natives.<br />
(They do not follow instructions and spray<br />
glyphosate over native vegetation resulting in<br />
loss of some native plants).<br />
Green Corps employed to do follow-up, wiping<br />
individual plants.<br />
Numbers of plants so reduced that only a few<br />
isolated plants left for Friends to deal with.
Number of Watsonia<br />
Chapter 4 Corms, Bulbs and Tubers Case Studies<br />
350<br />
300<br />
250<br />
200<br />
150<br />
100<br />
50<br />
0<br />
Figure 1. Number of Watsonia meriana in<br />
plots (1 m x 1 m) along a transect through<br />
the population in Shenton <strong>Bushland</strong> in 1999,<br />
2000 and 2001.<br />
Brixton Street Wetlands<br />
1999<br />
2000<br />
2001<br />
0 20 40 60 80<br />
Distance along transect (m)<br />
Introduction and spread: There<br />
are at least four species of Watsonia<br />
in the Brixton Street Wetlands;<br />
W. borbonica, W. versfeldii,<br />
W. meriana and W. meriana var.<br />
bulbillifera. At present only<br />
W. meriana and W. meriana var.<br />
bulbillifera form dense infestations.<br />
Garden refuse, soil movement and<br />
work along the adjoining railway<br />
line could all have brought in seed<br />
and vegetative material. Seed or<br />
cormels may also have come in<br />
with water movement or birds.<br />
Spread appears to be mainly by a<br />
slow expansion of populations via<br />
corms, cormels and possibly<br />
seed. Occasionally however,<br />
isolated plants are found 100<br />
metres or more from the main<br />
population in undisturbed bushland<br />
indicating cormels or seed are<br />
dispersed by birds, other animals<br />
or human activity.<br />
Distribution: Only a few scattered<br />
plants of W. versfeldii and<br />
W. borbonica have been found in the<br />
wetlands. The one dense infestation<br />
of W. meriana that was invading the<br />
highly disturbed area of Viminaria<br />
shrubland has been eradicated by<br />
the Friends of Brixton Street. The<br />
focus of this study was a dense<br />
infestation of W. meriana var.<br />
bulbillifera invading understorey of<br />
the Marri woodland.<br />
Response to treatment: The<br />
number of W. meriana var.<br />
bulbillifera plants remaining after<br />
two years treatment (Figure 2)<br />
indicates that intensive follow-up<br />
will be required for a number of<br />
years in this site also. Once again<br />
much smaller plants arising from<br />
small corms not seed, made up the<br />
population in the years following<br />
the initial treatment.<br />
Number of Watsonia<br />
350<br />
300<br />
250<br />
200<br />
150<br />
100<br />
50<br />
0<br />
0 10 20 30 40 50<br />
Distance along transect (m)<br />
Figure 2. Number of Watsonia meriana var.<br />
bulbillifera in plots (1 m x 1 m) along a<br />
transect through the population in Brixton<br />
Street Wetlands, 1999, 2000 and 2001.<br />
Talbot Road <strong>Bushland</strong><br />
Introduction and spread: Bulbils<br />
or seeds may have come in on<br />
maintenance machinery doing<br />
works along a drain near the main<br />
infestation. Water and soil<br />
movement may also have brought<br />
material in. Movement into good<br />
bushland appears to have been<br />
facilitated by soil disturbance<br />
associated with track maintenance.<br />
Distribution: A dense infestation<br />
of W. meriana var. bulbillifera<br />
occurs in disturbed Marri woodland<br />
on the eastern boundary, extending<br />
into good bushland for around 40<br />
metres. Occasional isolated plants<br />
are found in undisturbed bushland<br />
a long way from the main<br />
infestation suggesting birds or other<br />
animals are playing a role in spread<br />
of cormels and perhaps seed.<br />
Response to treatment: The<br />
population of W. meriana var.<br />
bulbillifera was effectively<br />
controlled in the first year of<br />
treatment. No smaller plants came<br />
back into the sites and the small<br />
amount of follow-up required was<br />
on large plants missed the first time<br />
around (Figure 3).<br />
What do the results tell us?<br />
1999<br />
2000<br />
2001<br />
Watsonia meriana var. bulbillifera<br />
responded quite differently to<br />
treatment at Talbot Road than at<br />
Brixton Street. It appears this is<br />
because the population at Talbot<br />
Number of Watsonia<br />
350<br />
300<br />
250<br />
200<br />
150<br />
100<br />
50<br />
0<br />
1999<br />
2000<br />
2001<br />
0 10 20 30 40 50<br />
Distance along transect (m)<br />
Figure 3. Number of Watsonia meriana var.<br />
bulbillifera in plots (1 m x 1 m) along a<br />
transect through the population in Talbot<br />
Road <strong>Bushland</strong>, 1999, 2000 and 2001.<br />
Road was initially sprayed with a 1<br />
% solution of glyphosate rather<br />
than wiped with 10 % solution, but<br />
site differences may also have<br />
played a role. Brixton Street is a<br />
denser population on a much<br />
wetter site. Whatever the cause,<br />
intensive follow-up will be required<br />
at the Brixton Street site for a<br />
number of years. Spraying<br />
glyphosate is not an option in<br />
bushlands where Watsonia grows<br />
closely among native flora. The<br />
Shenton <strong>Bushland</strong> population of<br />
W. meriana is also going to require<br />
intensive follow-up for a number of<br />
years. Why large numbers of<br />
smaller plants continue to come up<br />
each year at this site also is difficult<br />
to explain – age and density of the<br />
population and site conditions may<br />
all be playing a role.<br />
Understanding the biology of<br />
Watsonia and monitoring<br />
populations is clearly important if<br />
this weed is to be effectively<br />
managed. This case study highlights<br />
the importance of assessing invasive<br />
weeds on a site-specific basis and<br />
the necessity of resources to be<br />
made available over the long term.<br />
The results of the monitoring also<br />
provided the impetus to look for<br />
more effective methods and trials<br />
with the herbicide Dalapon (2,2-DPA)<br />
in Shenton <strong>Bushland</strong> are looking<br />
promising. This herbicide has been<br />
used on roadside populations of<br />
Watsonia in the Albany region for<br />
many years (J. Moore pers. comm.).<br />
47
48<br />
Chapter 4 Corms, Bulbs and Tubers Case Studies<br />
Case study 4.3 Control of Taro (Colocasia esculenta) and subsequent regeneration of the<br />
native plant community – a case study from along the Gingin Brook<br />
Illustration: IFAS Center for Aquatic<br />
Plants 1996.<br />
The study site was located along a<br />
section of the Gingin Brook in the<br />
town site where Swamp Paperbark<br />
(Melaleuca rhaphiophylla) and<br />
Flooded Gum (Eucalyptus rudis)<br />
form the main overstorey in the<br />
fringing vegetation and Tall Sedge<br />
(Carex appressa), Tassel Sedge<br />
(Carex fascicularis) and the fern<br />
Cyclosorus interruptus the<br />
understorey. Where Taro invades it<br />
completely displaces the<br />
understorey and allows no<br />
regeneration of overstorey species.<br />
Small population of Taro, before treatment<br />
May 1999.<br />
Physically removing isolated<br />
population in summer 1999<br />
Physically removing small (up to 10<br />
m x 10 m) outlying populations, was<br />
initially tried in the summer of 1999.<br />
The work was quite labour intensive<br />
with corms weighing around five<br />
kilos and the biomass left to dispose<br />
of significant. Follow-up work was<br />
required for the next two years and<br />
involved removing small plants that<br />
was regrowth from pieces left<br />
behind. Although effective on smaller<br />
populations, physical removal was<br />
not practical for larger infestations.<br />
Herbicide treatment in the<br />
summer of 2000<br />
In December 2000, following some<br />
preliminary trials, all Taro (around<br />
one hectare) was cut to the base<br />
and the bases painted with a 50 %<br />
glyphosate solution. These plants<br />
were up to two to three meters high<br />
and beyond the reach of a backpack<br />
unit. Six weeks later the regrowth,<br />
less than one metre high, was<br />
carefully spot sprayed with a 2 %<br />
glyphosate solution + metsulfuron<br />
methyl (0.05 g/L + Pulse ® 2 mL/L). A<br />
small 750 mL hand held sprayer was<br />
used to carefully target Taro<br />
regrowth. The glyphosate provided<br />
a relatively fast knock-down of top<br />
growth so the area covered could<br />
easily be seen.<br />
A bare open patch was left following<br />
removal in February 2000.<br />
Results from the<br />
monitoring transect<br />
Information collected along a<br />
transect run from the native<br />
vegetation into the Taro infestation<br />
showed the treatment was<br />
effective (Table 1).<br />
Regeneration of the native plant<br />
communities – photo points<br />
from the preliminary trials<br />
Preliminary trials over the summer<br />
of 1999/2000 provided the basis to<br />
treat the entire population of Taro in<br />
this way. Fixed photo points at those<br />
trial sites showed the treatment was<br />
effective. In addition, they showed<br />
rapid regeneration of the native<br />
plant community. Photo points can<br />
provide useful information when the<br />
changes are visually dramatic and<br />
the plant community relatively<br />
simple. In this case the plant<br />
community went from almost 100 %<br />
cover of Taro to 100 % cover of<br />
native species over a couple of<br />
years. Only six species of natives<br />
made up that cover; Tall Sedge,<br />
Tassel Sedge, Swamp Paperbark and<br />
Flooded Gum all spread by seed,<br />
often in water flow, while Cyclosorus<br />
interruptus and Native Knotweed<br />
(Persicaria decipiens) spread rapidly<br />
by vegetative means.<br />
Source: Brown and Brooks (in<br />
press b).<br />
By May 2001 native sedges, ferns and<br />
seedling paperbarks had colonised the<br />
open ground.
Chapter 4 Corms, Bulbs and Tubers Case Studies<br />
Table 1. December 2000–before treatment, February 2000–the regrowth, February 2002–one year after regrowth sprayed. Cover<br />
values: 1 (
50<br />
Chapter 4 Corms, Bulbs and Tubers Case Studies<br />
An integrated approach<br />
Initially it was thought the<br />
population could be managed with<br />
an intensive hand-weeding program.<br />
The first year this was tested it<br />
became evident it was going to be<br />
extremely labour intensive and<br />
expensive. Effective, affordable and<br />
appropriate control in the wetlands<br />
required a combination of carefully<br />
targeted hand-weeding and<br />
herbicide application.<br />
From 1999-2002 bush regenerators<br />
were employed in the wetlands<br />
through September/October to<br />
manually remove small isolated<br />
populations in undisturbed areas<br />
and populations growing around the<br />
edges of claypans where herbicide<br />
use is inappropriate. At this time of<br />
the year the wetland soils are still<br />
soft and entire plants including<br />
corms come out quickly and easily<br />
with minimal soil disturbance.<br />
Workers hand-removing Harlequin Flower in<br />
the wetlands<br />
Herbicide trials have indicated that<br />
Harlequin Flower can be controlled<br />
effectively with metsulfuron methyl<br />
(Brush-off ® ) at 2.5 g/ha (0.1 g/15 L)<br />
with limited impact on co-occurring<br />
native species in the Brixton Street<br />
Wetlands (Brown and Brooks in<br />
press c, Table 1). The Harlequin<br />
Flower populations are generally<br />
fairly discrete and are only ever<br />
spot sprayed. A spray contractor<br />
with a knowledge of the flora and a<br />
background in bushland work has<br />
been employed to carry out<br />
chemical control on heavier<br />
infestations in more disturbed areas<br />
and on the drier sites.<br />
To be effective over the three years<br />
the project has relied on workers<br />
having an understanding of the<br />
distribution of Harlequin Flower<br />
across the Brixton Street Wetlands.<br />
The populations were mapped at<br />
the start of the project in 1998.<br />
These maps helped set priorities<br />
and allowed for a carefully targeted<br />
works program revisiting small<br />
isolated populations over a number<br />
of years. The maps also enabled us<br />
to accurately record works carried<br />
out over time and will provide some<br />
information on the effectiveness of<br />
the management strategy.<br />
Figure 1. Distribution of Harlequin Flower • across the Brixton Street Wetlands, September 1998.<br />
Deep claypan (clay) - Melaleuca lateritia shrubland, Amphibromus grassland<br />
Wet flats - Viminaria juncea tall shrubland/dry flats - mixed low shrublands<br />
Shallow claypans (wet) - Pericalymma open heath<br />
Melaleuca shrubland<br />
Uplands - Marri Woodlands<br />
Disturbed areas<br />
Table 1. Native flora co-occurring with Harlequin Flower in the trial plots.<br />
Annual Herbs Perennial Herbs-Geophytes<br />
Aphelia cyperoides Burchardia congesta<br />
Centrolepis aristata Burchardia multiflora<br />
Drosera glanduligera Drosera menziesii ssp. menziesii<br />
Goodenia micrantha Philydrella drummondii<br />
Hydrocotyle alata Sowerbaea laxiflora<br />
Isolepis cernua Tribonanthes longipetala<br />
Schoenus odontocarpus Utricularia violacea<br />
Siloxerus humifusus Shrubs<br />
Perennial Herbs Acacia lasiocarpa var. bracteolata<br />
Borya scirpoidea Kunzea micrantha ssp. micrantha<br />
Chorizandra enodis Pimelea imbricata var. major<br />
Chorizandra multiarticulata Verticordia densiflora<br />
Cyathochaeta avenacea<br />
Juncus capitatus<br />
Lomandra spp<br />
Meeboldina canus<br />
Mesomelaena tetragona<br />
Viminaria juncea
Chapter 4 Corms, Bulbs and Tubers Case Studies<br />
Table 2. Management actions across Harlequin Flower populations in 1998 to 2001.<br />
YEAR ACTION/TREATMENT<br />
1998 Transects put in place over population. Numbers of Harlequin Flower in each 1 m x 1 m plot counted. No treatment.<br />
1999 Numbers of Harlequin Flower in plots counted again. Population appears to be expanding rapidly. Hand-weeding program<br />
attempted across wetlands and all plots hand-weeded.<br />
2000 Plots rescored. Also this year recorded cover estimates (Braun-Blanquet 1965) for all other species, weeds and natives, in plots.<br />
Hand-weeding program this year restricted to isolated populations and those in wetter areas. This population (being monitored)<br />
sprayed 2.5 g/ha Brush-off ® + Pulse ® 2 mL/L.<br />
2001 Plots rescored and control program continued as for 2000.<br />
More detailed monitoring<br />
over time<br />
In September 1998 three 30 metre<br />
long transects were run from the<br />
disturbed edge of the bushland,<br />
through the Harlequin Flower<br />
population. Along each transect<br />
quadrats (1 m x 1m) were placed at<br />
five metre intervals. The aim was to<br />
monitor changes in the density of<br />
the Harlequin Flower population<br />
Average number of plants<br />
10<br />
5<br />
0<br />
1998 1999 2000 2001<br />
Year<br />
over time and to gain an<br />
understanding of the effectiveness<br />
of the management actions.<br />
The populations of mature (Figure<br />
2a) and juvenile Harlequin Flower<br />
(Figure 2b) increased from 1998 to<br />
1999 before a management program<br />
was in place. Hand-weeding was<br />
very effective (1999-2000) and so<br />
was the herbicide treatment (2000-<br />
2001). The increase in Harlequin<br />
a Average number of Sparaxis by<br />
year and distance from edge<br />
b<br />
Average number of juvenile Sparaxis<br />
by year and distance from edge<br />
25<br />
1-2 m<br />
500 1-2 m<br />
6-7 m<br />
6-7 m<br />
20<br />
12-13 m<br />
18-19 m<br />
400<br />
12-13 m<br />
18-19 m<br />
24-25 m<br />
24-25 m<br />
15<br />
29-30 m 300<br />
29-30 m<br />
Average number of plants<br />
200<br />
100<br />
0<br />
1998 1999 2000 2001<br />
Year<br />
Figure 2. a) Average number of mature (flowering) Harlequin Flower plants and b) juvenile<br />
Harlequin Flower plants in plots (1 m x 1 m) along three 30 metre transects over four years<br />
(ie three replicates used).<br />
Flower one to two metres from the<br />
edge over 2000-2001 may indicate<br />
that the area missed herbicide<br />
treatment. If so it illustrates that<br />
there will be reinvasion of<br />
populations if follow-up is not<br />
consistent in the early years of the<br />
control program.<br />
Funding<br />
Funds have to be sought by the<br />
Friends of Brixton Street Wetlands<br />
each year to continue the work.<br />
It is anticipated that the cost will<br />
drop after the first three years.<br />
Unless the control program is<br />
consistently applied each year in<br />
the early stages, reinvasion will<br />
probably eventuate.<br />
The work at Brixton Street illustrates<br />
that with some resources and a<br />
carefully targeted and consistent<br />
effort over time, effective control of<br />
seriously invasive geophytes like<br />
Harlequin Flower moving into<br />
undisturbed bushland is possible with<br />
minimum off-target damage to cooccurring<br />
native species.<br />
Source: Brown and Brooks<br />
(in press c)<br />
Table 3. Cost of works, including funding sources, over three years. * A number of volunteers assisted the bush regenerators with<br />
their work in the wetlands<br />
TREATMENT RATE 2000 2001 2002<br />
Physical removal<br />
( 2 x bush regenerators) *<br />
48 hrs @ $17.50 x 2 $1,680.00 $1,680.00 $1,680.00<br />
Spot spray dense<br />
infestations (contractor)<br />
$60.00 per hour $600.00 $600.00 $300.00<br />
Total $2,280.00 $2,280.00 $1,980.00<br />
Funding source Wildflower Society W.A Dept. of Conservation Dept. of Conservation<br />
(Inc.) Perth branch & Land Management & Land Management<br />
51
Chapter 4 Corms, Bulbs and Tubers Weed Management Table<br />
Family Species Common name Storage organ Reproductive unit Dispersal agent Time to first<br />
flowering (years)<br />
Flowering Seedbank<br />
persistence<br />
(years)<br />
Hyacinthaceae Albuca canadensis bulb offsets, bulbils, seed 2-3 Sept-Oct short<br />
Alliaceae Allium triquetrum Angle Onion, Threecornered<br />
Garlic<br />
52<br />
bulb offsets, seed water, soil 2 Aug-Oct<br />
Amaryllidaceae Amaryllis belladonna Belladonna Lily bulb p offsets, seed birds, water, soil 5 Feb-Apr short<br />
Asparagaceae Asparagus asparagoides Bridal Creeper rhiz/tub p rhiz/tub, seed birds, water, soil 2-3 Aug-Sept 2-3 if buried<br />
Asparagaceae Asparagus declinatus Bridal Veil rhiz/tub p rhiz/tub, seed birds, water, soil 2-3 Apr-Aug medium?<br />
Asparagaceae Asparagus densiflorus Asparagus Fern rhiz/tub p rhiz/tub, seed birds, water, soil Mar medium?<br />
Asparagaceae Asparagus scandens Climbing Asapargus rhiz/tub p rhiz/tub, seed birds, water, soil Aug-Sep medium?<br />
Iridaceae Babiana angustifolia Babiana, corm ar<br />
Baboon Flower<br />
offsets, seed<br />
water, soil Jul-Nov medium?<br />
Iridaceae Babiana nana corm ar offsets, seed<br />
water, soil Aug-Sep medium?<br />
Iridaceae Babiana tubulosa corm ar offsets, seed water, soil Jul-Aug medium?<br />
Colchicaceae Baeometra uniflora corm Aug-Dec<br />
Iridaceae Chasmanthe floribunda African Corn Flag corm ar offsets, seed birds, water, soil 2-3 Jul-Oct<br />
Araceae Colocasia esculenta Taro corm p offsets, vegetativefragments<br />
water, soil Mar-Jul<br />
Amaryllidaceae Crinum moorei bulb p 3 short<br />
Iridaceae Ferraria crispa Black Flag corm p corms, seed soil Aug-Oct medium?<br />
Iridaceae Freesia alba x leichtlinii Freesia corm ar offsets, stem-cormels,<br />
seed<br />
water, soil, birds 2- Jul-Oct short?<br />
Iridaceae Gladiolus angustus Long Tubed corm ar<br />
Painted Lady<br />
offsets, seed?, cormels soil, water Aug-Nov*<br />
Iridaceae Gladiolus caryophyllaceus Pink Gladiolus corm ar d offsets, seed wind Aug-Nov medium?<br />
Iridaceae Gladiolus undulatus Painted Lady, corm ar<br />
Wavy Gladiolus<br />
offsets, seed, cormels soil, water Oct-Dec* medium?<br />
Iridaceae Hesperantha falcata Hesperantha corm ar offsets? seed water, soil Aug-Oct medium?<br />
Iridaceae Homoglossum watsonium Red Afrikaner corm Aug-Nov<br />
Alliaceae Ipheion uniflorum Spring Starflower bulb Sept-Nov<br />
Iridaceae Ixia maculata Yellow Ixia corm ar cormels on stolons, seed Aug-Oct medium?<br />
Iridaceae Ixia paniculata Tubular Corn Lily, Long<br />
Tubed Ixia<br />
corm ar seed Sep-Nov medium?<br />
Iridaceae Ixia polystachya Variable Ixia corm ar variable seed set Sep-Dec<br />
Hyacinthaceae Lachenalia aloides Soldiers bulb ar seed water, soil 2-3 Oct medium?<br />
Hyacinthaceae Lachenalia bulbifera bulb ar bulbils on leaves and<br />
stolons, seed<br />
soil, water 2-3 Sep medium?bulbils<br />
Hyacinthaceae Lachenalia mutabilis bulb ar seed water, soil 2-3 Sep medium?<br />
Hyacinthaceae Lachenalia reflexa Yellow Soldier bulb ar bulbils on leaves seed water, soil 2-3 Jul-Aug medium?<br />
Orchidaceae Monadenia bracteata South African Orchid tuber p seed wind Oct-Nov 6+<br />
Iridaceae Moraea flaccida One Leaf Cape Tulip corm ar d offsets seed water, soil 2-3 Sept-Nov less than 8<br />
Iridaceae Moraea fugax corm ar seed, cormels 3 Oct-Nov<br />
Iridaceae Moraea lewisiae corm ar offsets, seed soil, water, birds 3 Sept-Oct<br />
Storage organ: rhi=rhizome tub=tuber Renewal: ar=annually renewed p=perennial d=some dormancy between fire<br />
Reproductive units: bold=main method of dispersal Flowering: period over which plants flower Seedbank persistence: how long seed remains<br />
viable short=days to 1yr, medium=1-5yr
Suggested method of management and control Timing References<br />
Spot spray metsulfuron methyl 0.2 g/15 L + glyphosate 1% .<br />
Spot spray glyphosate 1 % + Pulse ®<br />
171, 242, 108, 101,<br />
167<br />
or metsulfuron methyl 0.15 g/10 L + Pulse ® . Just before flowering. 242, 231, 30, 248, 102,<br />
108, 167, 263<br />
Spot spray glyphosate 1 % + Pulse ®. After flowering just as new leaves emerge. 242, 167, 108<br />
Spray glyphosate 1 % + Pulse ®<br />
Chapter 4 Corms, Bulbs and Tubers Weed Management Table<br />
or metsulfuron methyl 0.04 g/10 L + Pulse ® . Best results when flowering. 242, 167, 270, 264,<br />
346, 222<br />
Spray glyphosate 1 % + Pulse ® . Best results when flowering. 242, 101, 167, 222<br />
Try 1 % glyphosate + 1 g metsulfuron methyl + 25 mL Pulse ® in 10 L water. Best results when flowering. 242, 101, 167, 222<br />
Try 100 mL glyphosate + 1 g metsulfuron methyl + 25 mL Pulse ® in 10 L water. Best results when flowering. 242, 167, 222<br />
Spot spray metsulfuron methyl 0.2 g/15 L + glyphosate 1 % . Just on flowering at corm exhaustion. 242, 167, 196, 101<br />
Spot spray metsulfuron methyl 0.2 g/15 L + glyphosate 1% . Just on flowering at corm exhaustion. 242, 167, 196, 101<br />
Spot spray metsulfuron methyl 0.2 g/15 L + glyphosate 1% . Just on flowering at corm exhaustion. 242, 167, 196, 101,<br />
181<br />
Spot spray glyphosate 1 % + Pulse ® . Before flowering. 242, 167, 108, 222<br />
Cut plants to base, paint metsulfuron methyl 0.05 g/L + glyphosate 50 % . Six weeks later carefully spray<br />
regrowth metsufuron methyl 0.05 g/L + glyphosate 1 % + Pulse ® .<br />
Hand-remove very small populations, sift soil to find all corms. Some control spraying metsulfuron methyl<br />
0.2 g/15 L + glyphosate 1 % .<br />
In summer when actively growing. Some reports suggest<br />
later in summer is more effective.<br />
242, 167<br />
44, 128, 41, 167<br />
108, 167<br />
When flowering. 242, 167, 108, 101<br />
Spot spray metsulfuron methyl 0.2 g/15 L + Pulse ® (2.5-5 g/ha). Just on flowering at corm exhaustion. 242, 167, 108, 253<br />
Spot spray metsulfuron methyl 0.2 g/15 L + glyphosate 1 % + Pulse ® in degraded sites. Physical removal<br />
can result in spread of cormels.<br />
Just on flowering? Once parent corm killed cormels in soil<br />
lose dormancy and germinate.<br />
242, 167, 108, 140<br />
Wipe individual leaves glyphosate 10 % , spray dense infesations in degraded area 1 % glyphosate. Just on flowering at corm exhaustion. 242, 167, 108, 160,<br />
140<br />
Spot spray metsulfuron methyl 0.2 g/15 L + glyphosate 1 % in degraded sites. Physical removal can result in<br />
spread of cormels.<br />
Just on flowering? Once parent corm killed cormels in soil<br />
lose dormancy and germinate.<br />
181, 242, 108, 140<br />
Spot spray metsulfuron methyl 0.2 g/15 L + Pulse ® (2.5-5 g/ha). Just on flowering at corm exhaustion. 242, 167, 108<br />
Spot spray metsulfuron methyl 0.2 g/15 L + glyphosate 1 %. Just on flowering at corm exhaustion. 242, 101, 167<br />
Spot spray metsulfuron methyl 0.2 g/15 L + glyphosate 1 %. Just on flowering at corm exhaustion. 242, 101, 266, 167<br />
Spot spray metsulfuron methyl 0.2 g/15 L + glyphosate 1 %. Just on flowering at corm exhaustion. 181, 167<br />
Try as for L. reflexa. Just on flowering at bulb exhaustion. 242, 167, 109<br />
Try as for L. reflexa. Physical removal can result in spread of bulbils. Just on flowering at bulb exhaustion. 242, 167, 109<br />
Try as for L. reflexa. Just on flowering at bulb exhaustion. 242, 167, 109<br />
Spot spray metsulfuron methyl 0.2 g/15 L + Pulse ® (2.5g-5g/ha). Just on flowering at bulb exhaustion. 242, 46, 167, 109<br />
Spot spray glyphosate 1 % + Pulse ® . Just on flowering. 30, 242, 101, 167<br />
Spot spray metsulfuron methyl 0.1 g/10 L or chorsulfuron 0.2 g/10 L + Pulse ® . Just on flowering at corm exhaustion. 242, 167, 248, 138,<br />
253,<br />
Try as on M. miniata. Just on flowering at corm exhaustion. 108, 167<br />
Try as on M. miniata. Just on flowering at corm exhaustion. 242, 167, 138, 108, 5<br />
266, 167<br />
53
Iridaceae Moraea miniata Two Leaf Cape Tulip corm ar d offsets, cormels on stem<br />
and base<br />
54<br />
Family Species Common name Storage organ Reproductive unit Dispersal agent Time to first<br />
flowering (years)<br />
water, soil, birds,<br />
Cyclone Albey<br />
2-3 Jul-Nov cormels 8<br />
Iridaceae Moraea setifolia Thread Thread Iris Iris corm ar offsets, seed water, soil 3 Sept-Jan<br />
Hyacinthaceae Muscari comosum Grape Hyacinth<br />
bulb offsets, seed water, soil, birds Sep<br />
Amaryllidaceae Narcissus papyraceus Paperwhite<br />
bulb p offsets, seed soil, water Aug-Sep<br />
Alliaceae Nothoscordum gracile False Onion Weed<br />
bulb bulbils, seed soil, water Oct-Jan<br />
Hyacinthaceae<br />
Chapter 4 Corms, Bulbs and Tubers Weed Management Table<br />
Ornithogalum thyrsoides Cincherinchee<br />
bulb seed water Oct-Nov<br />
Oxalidaceae Oxalis depressa bulb ar May-Jun<br />
Oxalidaceae Oxalis flava Pink Bulb Soursob bulb ar bulbils soil May<br />
Oxalidaceae Oxalis glabra Finger Finger Leaf Leaf Oxalis Oxalis bulb ar bulbils soil May-Aug<br />
Oxalidaceae Oxalis incarnata Pale-flowered Oxalis bulb ar bulbils soil Aug-Nov<br />
Oxalidaceae Oxalis pes-caprae Soursob Soursob bulb ar bulbils soil Jun-Oct<br />
Oxalidaceae Oxalis purpurea Four o'clock, Largeflowered<br />
Wood Sorrel<br />
bulb ar bulbils soil May-Sep<br />
Amaryllidaceae Pancratium maritimum bulb offsets, seed Aug-Oct<br />
Iridaceae Romulea flava corm ar seed 2 Jul-Sep medium?<br />
Iridaceae Romulea obscura corm ar seed 2 medium?<br />
Iridaceae Romulea rosea Guildford grass<br />
corm ar seed 2 Aug-Oct medium?<br />
Iridaceae Sparaxis bulbifera Harlequin Flower<br />
corm ar offsets, cormels on stem,<br />
seed<br />
water, soil 2-3 Sep-Oct short?<br />
Iridaceae Sparaxis pillansii Harlequin Flower<br />
corm ar seed Sep-Oct short?<br />
Iridaceae Watsonia borbonica corm ar d offsets, seed? wind, water, soil 2-3 Sep-Nov medium?<br />
Iridaceae Watsonia marginata Fragrant Bugle Lily corm ar d offsets, seed water, soil, wind 2-3 Oct-Dec medium?<br />
Iridaceae Watsonia meriana Bugle Watsonia<br />
corm ar d offsets, seed water, soil, wind 2-3 Sep-Dec medium?<br />
Iridaceae Watsonia meriana<br />
var.bulbillifera<br />
Bulbil Watsonia<br />
corm ar d offsets, cormels on stem<br />
and base, seed<br />
Flowering Seedbank<br />
persistence<br />
(years)<br />
water, soil, wind 2-3 Sep-Dec medium?<br />
Iridaceae Watsonia versfeldii corm ar d offsets, seed water, soil, wind 2-3 Sep-Nov medium?<br />
Araceae Zantedeschia aethiopica Arum Arum Lily Lily tub/rhiz p offsets, seed water, birds, soil Jun-Nov short<br />
Storage organ: rhi=rhizome tub=tuber Renewal: ar=annually renewed p=perennial d=some dormancy between fire<br />
Reproductive units: bold=main method of dispersal Flowering: period over which plants flower Seedbank persistence: how long seed remains<br />
viable short=days to 1yr, medium=1-5yr
Suggested method of management and control Timing References<br />
or chorsulfuron 0.2 g/10 L + Pulse Just on flowering at corm exhaustion. 242, 167, 248, 138,<br />
in spread of cormels.<br />
253, 5<br />
Try as on M. miniata. Just on flowering at corm exhaustion. 242, 167, 138, 108<br />
® Spot spray metsulfuron methyl 0.1 g/10 L<br />
. Physical removal can result<br />
Try 1 % glyphosate + 0.1 g metsulfuron methyl + 25 mL Pulse ® in 10 L water.<br />
Chapter 4 Corms, Bulbs and Tubers Weed Management Table<br />
Spray metsulfuron methyl 0.2 g/15 L + glyphosate 1 %. Just before flowering. 108, 167<br />
Try 1 % glyphosate + 0.1 g metsulfuron methyl + 25 mL Pulse ® in 10 L water. Just on flowering. 101, 167, 222<br />
1 g of metsulfuron methyl in 10 L of water + Pulse ® gives partial control. Before flowering. 300, 228, 167, 222<br />
As for O. pes-caprae. At bulb exhaustion, generally just on flowering. 242, 2, 167<br />
As for O. pes-caprae. At bulb exhaustion, generally just on flowering. 242, 167, 40<br />
As for O. pes-caprae. At bulb exhaustion, generally just on flowering. 242, 167, 40<br />
Spot spray metsulfuron methyl 0.2 g/15 L + Pulse or 1 % glyphosate . Physical removal can result in<br />
spread of bulbils.<br />
® ,<br />
At bulb exhaustion, generally just on flowering. 242, 167, 181, 40<br />
At bulb exhaustion, generally just on flowering. 242, 167, 248, 252, 40<br />
As for O. pes-caprae. At bulb exhaustion, generally just on flowering. 242, 167, 250, 40<br />
Try as for R. rosea. Just on flowering at corm exhaustion. 181, 108, 167<br />
Try as for R. rosea. Just on flowering at corm exhaustion. 181, 108, 167<br />
Spot spray metsulfuron methyl 0.2 g/15 L + Pulse ® . Just on flowering at corm exhaustion. 102, 108, 167<br />
or chlorsulfuran 0.3 g/10 L + Pulse ® Spot spray metsulfuron methyl 0.1 g/15 L +Pulse Just on flowering at corm exhaustion. 242, 167, 45, 222<br />
®<br />
Try as for S. bulbifera. Just on flowering at corm exhaustion. 242, 167<br />
As for W. meriana var. bulbillifera. Just on flowering at corm exhaustion. 242, 194, 108, 167<br />
As for W. meriana var. bulbillifera. Just on flowering at corm exhaustion. 242, 139, 108, 167<br />
As for W. meriana var. bulbillifera. Just on flowering at corm exhaustion. 242, 139, 108, 167<br />
Wipe individual leaves glyphosate 10 % or spray dense infesations 2,2-DPA 10 g/L + wetting agent or in<br />
degraded area 1 % glyphosate.<br />
222<br />
181, 167<br />
Just as flower spikes emerge at corm exhaustion. 242, 139, 108, 167<br />
As for W. meriana var. bulbillifera. Just as flower spikes emerge at corm exhaustion. 242, 139, 108, 167<br />
Spot spray metsulfuron methyl or chlorsulfuron 0.4 g/15 L of water + Pulse<br />
litre hand held sprayer applying a single squirt to leaves avoids off target damage.<br />
® . Higher concentration in one<br />
Any time between June and September. Early prevents<br />
flowering and seed set but may miss later sprouting tubers.<br />
223, 227, 270, 42, 167<br />
55
Chapter 5 Broadleaf Herbs,<br />
Sedges and Succulents<br />
56<br />
Herbs are seed plants with non-woody green stems.<br />
Grasses and geophytes, both classified as herbs, have<br />
been covered in previous chapters. This chapter covers<br />
the rest of the weedy herbs. The information is<br />
presented in two sections – those broadleaf herbs with<br />
an annual life-cycle and then the sedges, succulents and<br />
broadleaf herbs with a perennial life-cycle. With their<br />
small biomass and ephemeral nature, annuals are often<br />
not serious weeds of bushland. Perennial weeds on the<br />
other hand, are persistent over time, can form a large<br />
biomass and tend to have a much greater impact on<br />
native plant communities.<br />
Annual herbs<br />
As a group, annual herbs share similar life-cycles and<br />
reproductive biology. They also often share common<br />
management and control strategies.<br />
Annual plants complete their full life-cycle from<br />
germination to seed production within one year and then<br />
die. As their life expectancy is short, they are favoured<br />
where frequency of habitat disturbance is high (Hobbs<br />
and Atkins 1988, McIntyre et al. 1995, Sheppard 2000).<br />
They are among the most commonly occurring weeds on<br />
the disturbed edges of bushland. Soil disturbance and<br />
nutrient run-off in particular, facilitate the rapid<br />
establishment of weeds with an annual life-cycle.<br />
In south west Western Australia, most annual weeds<br />
germinate with the first autumn rains, grow actively<br />
over the winter spring period and set seed and die with<br />
the onset of higher temperatures in summer. In<br />
wetlands though, some annual weeds germinate as<br />
water levels drop in spring, grow actively over the<br />
summer months setting seed in autumn. Examples of<br />
the latter include Bushy Starwort (Symphyotrichum<br />
subulatum) and Prickly Lettuce (Lactuca serriola).<br />
Others can germinate and go through to flowering<br />
whenever conditions are suitable, often several times<br />
over the one year. Caltrop (Tribulus terrestris) and<br />
Doublegee (Emex australis) are good examples.<br />
Impacts<br />
Although there are large numbers of introduced annual<br />
herbs there are only a few species that are serious<br />
weeds of bushland in south west Western Australia.<br />
Many co-exist among native plant communities without<br />
having much of an impact and are often not a high<br />
priority for management. However, it is important to<br />
consider the impacts of particular annual weeds at<br />
individual sites and over several seasons. There are a<br />
number that can be serious weeds in particular plant<br />
communities and under certain seasonal conditions.<br />
For example, Lupins (Lupinus angustifolius, Lupinus<br />
consentinii) are one of the more serious annual weeds in<br />
Banksia woodland around Perth. They can form dense<br />
stands that prevent regeneration of native plants and<br />
alter the soil chemistry through nitrogen fixation<br />
(Swarbrick and Skarratt 1994). Each year Fumitory<br />
(Fumaria capreolata) grows up and smothers native<br />
shrubs and seedlings among the understorey of Banksia<br />
woodlands. The seed remains viable in the soil for<br />
several years (Chancellor 1996, Peltzer and Matson 2002)<br />
germinating with the onset of any disturbance. Isolepis<br />
hystrix is emerging as a serious annual weed of clay-based<br />
wetlands where it forms dense mats, competing with the<br />
rich native annual flora (Keighery 1999c).<br />
Annual weeds can have a serious impact where they<br />
invade native herbfields on granite outcrops (Hopper et<br />
al. 1996, Pigott and Sage 1996) and the herbaceous<br />
understorey of York Gum (Eucalyptus loxophleba) – Jam<br />
(Acacia acuminata) woodlands. They are also often<br />
prolific on the highly degraded edges of bushland.<br />
Restoring these sites often involves dealing with<br />
continual germination of annual weeds competing with<br />
regenerating natives.<br />
Management and control<br />
Management and control of this group of weeds is about<br />
preventing germination and seed set. On highly degraded<br />
edges it may sometimes involve restoring/re-establishing<br />
the cover of some local species that will displace and<br />
out-compete annual weeds and prevent further dispersal<br />
of weed seed into undisturbed areas.<br />
Preventing establishment<br />
Minimising soil disturbance<br />
Persistence of annual weeds at a site is often due to a<br />
long-lived soil seedbank that will germinate with the<br />
onset of any disturbance. Often the soil disturbance<br />
brought about by removal of perennial weeds is enough<br />
to stimulate germination of annual weed seed that has<br />
lain dormant in the soil. As soon as space and light<br />
become available dormancy is broken, seeds germinate<br />
and seedlings establish (Box 5.1).<br />
Box 5.1 Black Nightshade – a disturbance<br />
opportunist<br />
An isolated clump of Arum Lily removed from among<br />
native sedges and ferns along the Gingin Brook was<br />
very quickly replaced by a dense monoculture of the<br />
annual Black Nightshade (Solanum nigrum). Seed of<br />
Black Nightshade can remain viable in the soil for up<br />
to eight years and dormancy can be broken by light<br />
(Thullen and Keeley 1982). Black Nightshade will<br />
need to be controlled until the soil seedbank is<br />
exhausted or native perennials fill the gap and<br />
prevent further germination.<br />
A patch of Black Nightshade coming up where an isolated clump<br />
of Arum Lily has been physically removed.<br />
Illustration provided by: IFAS, Centre for Aquatic Plants University<br />
of Florida, Gainesville, 1996
Chapter 5 Broadleaf Herbs, Sedges and Succulents<br />
Other annual weeds establish by rapidly dispersing<br />
into recently disturbed sites. Many annual weeds of the<br />
Swan Coastal Plain and Jarrah Forest belong to the<br />
daisy family (Asteraceae), a group with largely wind<br />
dispersed seed. They are able to disperse effectively<br />
into sites of soil disturbance, rapidly growing and<br />
exploiting available resources (McIntyre et al. 1995).<br />
Often the most prolific is the wind dispersed Flat Weed<br />
(Hypochaeris glabra) (Box 5.2).<br />
Box 5.2 Fire and soil disturbance in a<br />
Banksia woodland<br />
The disturbance caused by fire and then the handremoval<br />
of Yellow Soldier (Lachenalia reflexa), an<br />
introduced bulb, in study plots in Shenton <strong>Bushland</strong><br />
encouraged the establishment of weedy annuals.<br />
Fire<br />
The initial increase in cover of annual broadleaf<br />
weeds that occurred over 1998/1999 across all plots<br />
was probably a reflection of conditions following<br />
the October 1997 fire. The gaps created by the fire<br />
and the increased nutrient levels provide ideal<br />
conditions for annual weed establishment.<br />
Soil disturbance<br />
Where Yellow Soldier was removed by hand and<br />
the soil disturbed, the cover of annual weeds<br />
increased to an even greater degree. Flat Weed<br />
(Hypochaeris glabra) was the most prolific. With its<br />
wind dispersed seed and flat rosette of leaves it is<br />
a prime example of a weed able to disperse<br />
effectively and rapidly exploit available resources.<br />
Other broadleaf annual weeds colonising the plots<br />
included Ursinia (Ursinia anthemoides), French<br />
Catchfly (Silene gallica), and Slender Suckling<br />
Clover (Trifolium dubium). Any hand-removal<br />
program aimed at controlling bulbous weeds such<br />
as Yellow Soldier in Banksia woodland is likely to<br />
result in colonisation by annual weeds.<br />
Percentage Cover<br />
45<br />
40<br />
35<br />
30<br />
25<br />
20<br />
15<br />
10<br />
5<br />
0<br />
control<br />
hand removal<br />
herbicide<br />
1998 1999 2000<br />
Year<br />
Figure 1. The cover of weedy annual herbs in plots (2 m x 2 m)<br />
for three years following fire. Bars indicate standard errors.<br />
Keeping out fire<br />
Fire can also facilitate invasion of annual weeds into<br />
bushland. Weed seed builds up in the soil seedbank<br />
between fires. After fire many annual weed species<br />
germinate, exploit available resources and set seed<br />
before native species (Fisher 1998, Perez-Fernandez<br />
et al. 2002). In the two years following fire at Shenton<br />
<strong>Bushland</strong>, the cover of annual weeds at study sites<br />
increased greatly (Box 5.2).<br />
Assisting regeneration of the native plant<br />
community<br />
Management that favours the regeneration of native<br />
plant communities increases competition against<br />
weeds. Annual weeds, probably more than any other<br />
weeds, can be displaced and prevented from<br />
establishing through careful bush regeneration -<br />
encouraging regeneration of the native plant<br />
communities and allowing native plants to fill gaps<br />
(Bradley 1988, Vranjic et al. 2000). This can be a<br />
particularly useful tool when fast-growing native<br />
perennials are present (Box 5.3).<br />
Stimulating the native soil seedbank to germinate by<br />
the use of smoke or smoke-derived products (Dixon<br />
et al. 1995, Roche et al. 1998) is one way to encourage<br />
regeneration of the native plant community. At most<br />
disturbed sites weed management will be labour<br />
intensive and ongoing until a cover of native species is<br />
well established.<br />
Direct seeding with local provenance seed<br />
If there is no native soil seedbank remaining, as in<br />
many degraded sites on the edge of bushland (Fisher<br />
1998), then direct seeding the site is the next option.<br />
Consider the following:<br />
• The great diversity of native flora of south west<br />
Western Australia is recognised internationally.<br />
Less well known is the diversity we cannot see,<br />
hidden diversity in the genetic make up of our flora<br />
(Byrne 2002). In order to protect the integrity of<br />
that genetic diversity, always collect seed locally,<br />
i.e. from bushland adjoining the restoration site.<br />
Collecting seed for restoration work locally is, at<br />
present, the only way to avoid introducing nonlocal<br />
genetic material and non-local forms of plants<br />
to bushland. It also ensures plants established are<br />
adapted to local conditions (Box 5.4).<br />
• Ensure that the species selected occur on the soils<br />
and are from the plant community of the site that is<br />
being restored. Vegetation maps, species lists and<br />
near-by intact bushland are useful reference points.<br />
• Think about species selection. When the aim of the<br />
project is to displace annual weeds along a<br />
disturbed edge, think about selecting easy to<br />
establish, fast-growing species. Remember though,<br />
returning as much of the natural diversity to the<br />
site as possible is the long-term objective.<br />
• Weed control will be ongoing for many years until<br />
a cover of native plants is well established.<br />
57
58<br />
Chapter 5 Broadleaf Herbs, Sedges and Succulents<br />
• Success will often depend on at least one or two<br />
year’s site preparation and seed collection and a<br />
long-term access to resources for follow-up work.<br />
• Results will vary across sites, soils, seasons, plant<br />
communities and species selected.<br />
• Ensure appropriate permits have been acquired<br />
before seed collection is undertaken.<br />
Control methods<br />
There are 60 species of annual weeds listed in the table<br />
at the end of the chapter. Methods of control are often<br />
going to be quite specific for each species.<br />
Nevertheless, some useful generalisations can be made.<br />
Physical control<br />
• Hand-removal is only useful before seed set and all<br />
flowering material should be taken from a site. Left<br />
behind, it may well go on to produce seed.<br />
• Mowing or brushcutting can reduce seed production<br />
and reduce populations if carried out well before<br />
seed set. As slashing is non-specific it is really only<br />
useful in highly degraded sites. Work needs to be<br />
Box 5.3 Managing annual weeds after Arum Lily control – experience from the banks of<br />
Bennett Brook<br />
Trials on different methods to control Arum Lily along Bennett Brook highlight the invasive potential of annual<br />
weeds. The trials were located in a very degraded patch of Flooded Gum (Eucalyptus rudis) – Swamp<br />
Paperbark (Melaleuca rhaphiophylla) woodland. The understorey in most places was a monoculture of Arum<br />
Lily. <strong>Weeds</strong> that moved into areas where Arum Lily had been controlled included 12 species of annual weeds<br />
(nine broadleaf herbs and three species of annual grasses) (Table 1.).<br />
Interestingly, the only natives to move into the site were four species of herbaceous perennials, all of them<br />
fast-growing, easily-propagated, mat-forming plants highly suitable for displacing weeds, particularly those<br />
with an annual life-cycle. Such species are often present in disturbed wetland sites and they provide a great<br />
opportunity to quickly fill gaps, helping prevent further germination of annual weeds.<br />
Slender Knot Weed (Persicaria decipiens).<br />
Water Buttons (Cotula coronopifolia).<br />
Table 1. <strong>Weeds</strong> and natives that colonised the site following<br />
removal of Arum Lily.<br />
WEEDS<br />
Annual Grasses<br />
Annual Rye Grass Lolium sp.<br />
Annual Veldgrass Ehrharta longiflora<br />
Annual Barb Grass<br />
Perennial Grasses<br />
Polypogon monspeliensis<br />
Phalaris<br />
Annual Herbs<br />
Phalaris aquatica<br />
Bushy Starwort (annual or biennial) Symphyotrichum subulatum<br />
Pimpernel Anagallis arvensis<br />
Common Starwort Callitriche stagnalis<br />
Pattersons Curse Echium plantagineum<br />
Lesser Loosestrife Lythrum hyssopifolium<br />
Slender Birds Foot Trefoil Lotus angustissimus<br />
Plantain (or short-lived perennial) Plantago major<br />
Sow Thistle Sonchus oleraceus<br />
Sharp Buttercup<br />
Perennial Herbs<br />
Ranunculus muricatus<br />
Clustered Dock Rumex conglomeratus<br />
Water Cress<br />
NATIVES<br />
Perennial Herbs<br />
Rorippa nasturtium-aquaticum<br />
Juncus microcephalus<br />
Water Buttons Cotula coronopifolia<br />
Centella Centella asiatica<br />
Joy Weed Alternanthera nodiflora<br />
Slender Knot Weed Persicaria decipiens
Chapter 5 Broadleaf Herbs, Sedges and Succulents<br />
carefully timed; too early and some species will<br />
resprout. Slash too late (after seed set) and the result<br />
will be further spread of propagules and expanding<br />
populations of the weed the following year.<br />
Chemical control<br />
Spot spraying with glyphosate generally well before<br />
flowering is the recommended herbicide control for<br />
many annual weeds. There are some species of annual<br />
weeds not killed by glyphosate. Check the table at the<br />
end of the chapter.<br />
Box 5.4 Using local provenance seed in<br />
restoration (from Keighery et al. 1998)<br />
This is a list of species from Brixton Street<br />
Wetlands that can be easily propagated for<br />
restoration purposes. The list highlights the<br />
importance of using locally collected seed.<br />
Many species have locally occurring forms that<br />
could be lost with the introduction of genetic<br />
material (seeds or cuttings) from other areas.<br />
FAMILY/SPECIES<br />
Anthericaceae<br />
HABITAT PROPAGATION<br />
Sowerbaea laxiflora dry division/seed<br />
Tricoryne humilis<br />
Asteraceae<br />
dry division/seed<br />
Hyalosperma cotula dry/damp/wet seed<br />
# Podolepis gracilis<br />
Haemodoraceae<br />
damp/wet seed<br />
Anigozanthos manglesii<br />
Mimosaceae<br />
dry seed<br />
# Acacia lasiocarpa dry/damp seed<br />
# Acacia pulchella dry seed<br />
# Acacia saligna<br />
Myrtaceae<br />
dry seed<br />
# Astartea aff. fascicularis wet seed<br />
Baeckea camphorosmae dry/damp seed<br />
Eucalyptus calophylla dry seed<br />
Hypocalymma angustifolium dry/damp cuttings/seed<br />
Hypocalymma robustum dry cuttings/seed<br />
# Melaleuca rhaphiophylla wet seed<br />
# Melaleuca viminea wet seed<br />
Pericalymma ellipticum<br />
Papilionaceae<br />
damp/wet seed<br />
Kennedia prostrata dry/damp seed<br />
Viminaria juncea<br />
Proteaceae<br />
damp/wet seed<br />
# Grevillea bipinnatifida dry/damp cuttings/seed<br />
# Hakea trifurcata dry/damp seed<br />
# Hakea prostrata dry/damp seed<br />
# Hakea varia damp/wet seed<br />
Key # Species with recognised local variants Habitats dry = uplands<br />
damp = waterlogged areas wet = inundated areas.<br />
As glyphosate is non-specific it needs to be carefully<br />
targeted and is only useful in degraded sites where<br />
there is no danger of off-target damage.<br />
In direct seeding trials, the Main Roads Department<br />
has found that Lontrel at 500 mL/ha controls Lupins<br />
and Cape Weed in the early stages with little off-target<br />
damage to native species (Grist and Thompson 1997).<br />
Clopyralid, the active ingredient of Lontrel, is<br />
particularly effective on members of the Asteraceae<br />
(daisy family) and the Fabaceae (pea family).<br />
Important note: Lontrel can persist in the soil for several months, is<br />
not bound by soil particles, and is highly soluble. It should only be<br />
applied in bushland by well-qualified, responsible operators with a<br />
thorough knowledge of the native flora (see Chapter 8.).<br />
Key points<br />
• The majority of annual weeds do not have serious<br />
impacts in bushland and are often not a priority<br />
for management.<br />
• Annual weeds often germinate from soil stored<br />
seed or disperse into a site following removal of<br />
more serious perennial weeds.<br />
• Their management is then the next step in the<br />
restoration process – sometimes simply waiting for<br />
native perennials to fill the gap.<br />
• Preventing the establishment of annual herbs in<br />
bushland is about minimising soil disturbance,<br />
nutrient run-off and fires.<br />
• Limiting spread is about preventing or reducing<br />
seed set.<br />
• Restoration of native plant communities along the<br />
disturbed edges, either through germination of the<br />
native seedbank stored in the soil or direct<br />
seeding, is often part of a long-term solution to<br />
management of annual weeds.<br />
Perennial herbs<br />
Perennial plants have a life span that extends over two<br />
or more years. The perennial herbs covered in the<br />
table at the end of this chapter are a diverse group.<br />
They include everything from succulents and sedges to<br />
plants with underground storage organs, to<br />
Pelargonium and perennial members of the daisy<br />
(Asteraceae) family. They have a diverse range of lifecycles<br />
and mechanisms for spreading into bushland.<br />
As management and control strategies vary<br />
accordingly, it is not possible or useful to provide<br />
general information for the group as a whole.<br />
Instead, case studies are presented for three weedy<br />
perennial herbs of the Swan Coastal Plain and Jarrah<br />
Forest. They illustrate how some of the weeds in this<br />
group can be managed where they are invading<br />
bushland. Detailed control techniques and information<br />
on the biology for specific species that are serious<br />
weeds in the region are provided in the final table.<br />
59
60<br />
Chapter 5 Broadleaf Herbs, Sedges and Succulents<br />
Case Studies<br />
Case study 5.1 Direct seeding to manage annual weeds along a disturbed edge of Swish<br />
Bush (Viminaria juncea) shrublands<br />
Site history<br />
• The site has a long history of<br />
soil disturbance associated with<br />
track and drain maintenance.<br />
• Before 1995: The site was<br />
100 % covered by Watsonia<br />
meriana with a few emergent<br />
Swish Bushes. The Watsonia<br />
population provided a continual<br />
source of propagules to the<br />
adjoining intact bushland.<br />
• 1996 and 1997: The Friends<br />
of Brixton Street sprayed the<br />
Watsonia (1 % solution of<br />
glyphosate as flower spikes<br />
were emerging) for two<br />
consecutive years eradicating<br />
the population.<br />
• 1998 and 1999: Invasion by a<br />
large number of annual and a<br />
few perennial weeds followed.<br />
Early in the season Wild Radish<br />
(Raphanus raphanistrum), Wild<br />
Oat (Avena barbata) and<br />
Annual Veldgrass (Ehrharta<br />
longiflora) were prolific and<br />
later on Slender Suckling Clover<br />
(Trifolium dubium), Patersons<br />
Curse (Echium plantagineum),<br />
Lotus (Lotus angustissimus),<br />
Vicia (Vicia sativa) and Stagger<br />
Weed (Stachys arvensis)<br />
covered the site.<br />
• There was also some<br />
recruitment of native species,<br />
mostly isolated seedlings of<br />
shrubs including Swish Bush,<br />
Running Postman (Kennedia<br />
prostrata), and Acacia<br />
lasiocarpa var. bracteolata. The<br />
adjoining bushland is rich in<br />
native herbs and some of these<br />
also moved into the site,<br />
tending to colonise bare soil –<br />
Yellow Autumn Lily (Tricoryne<br />
elatior), Centrolepis aristata and<br />
Goodenia micrantha were the<br />
most common.<br />
• Given the resources available,<br />
hand-weeding was not an<br />
option. Spot spraying of 1 %<br />
glyphosate was required four<br />
times over the season as<br />
germination of soil stored weed<br />
seed continued.<br />
The Swish Bush shrublands at Brixton Street occur on winter-wet clay soils.<br />
• The management of this site in<br />
the longer term required<br />
restoration of native plant<br />
cover, particularly<br />
fast-growing perennials to<br />
displace, shade out and prevent<br />
continual germination of weedy<br />
annuals over the winter and<br />
spring seasons.<br />
• Trials with smoke water at the<br />
site in autumn 1999, indicated<br />
little viable native seed<br />
remained in the soil.<br />
The trial<br />
Seed collection and species<br />
selection<br />
Seed was collected from adjoining<br />
Swishbush shrublands over the<br />
summer. Species selected included<br />
five shrubs: Acacia lasiocarpa var.<br />
bracteolata, Swishbush, Hakea<br />
trifurcata, Running Postman and<br />
Verticordia densiflora. Seed was also<br />
collected from Foxtail Mulga Grass<br />
(Neurachne alopecuroidea) and<br />
Clustered Lovegrass (Eragrostis<br />
elongatus), chosen for their potential<br />
to occupy bare ground quickly.<br />
There was one disadvantage in using<br />
grasses; grass-selective herbicides<br />
could not be used in follow-up weed<br />
control as germinating native grass<br />
seedlings are susceptible.<br />
Site preparation and trials<br />
• The site was spot sprayed with<br />
1 % glyphosate twice over the<br />
autumn prior to setting up the<br />
direct seeding trial.<br />
• Prior to sowing, the soil surface<br />
in trial plots was very lightly<br />
raked to create microsites for<br />
seed germination and to<br />
prevent the seed blowing away.<br />
• Trial plots measured 2 m x 2 m<br />
and there were three replicates<br />
of two different seed mixes<br />
(shrubs only and shrubs and<br />
grasses) and a control – no seed.<br />
• The hard-seeded legumes<br />
(Acacia, Kennedia and<br />
Viminaria) were all soaked in<br />
just-boiled water for two hours<br />
prior to sowing.<br />
• Once seed was broadcast, plots<br />
were sprayed with Regen 2000<br />
(smoke water) diluted to 100<br />
mL/L (Lloyd et al. 2000). The<br />
aim was to break dormancy<br />
and stimulate germination of<br />
the Verticordia and the native<br />
grass seed.<br />
• Heavy rains fell in the days<br />
following sowing.
Chapter 5 Broadleaf Herbs, Sedges and Succulents<br />
Case Studies<br />
July 2000 just after direct seeding.<br />
Note: 1. Disturbing the soil to create a seed<br />
bed for germination can easily facilitate<br />
establishment of more weeds.<br />
2. Viability of seed was not determined<br />
before sowing but subsamples were set<br />
aside for the purpose should germination<br />
failure occur.<br />
The trials were hand-weeded twice<br />
and sprayed with grass-selective<br />
herbicide where appropriate in the<br />
winter season following sowing<br />
(2000). No weed control took place<br />
in 2001.<br />
Establishment of natives<br />
Two years after sowing, in June<br />
2002, all seeded plots had 100 %<br />
cover of natives. Hakea trifurcata<br />
formed the greatest cover in all<br />
plots followed by Acacia lasiocarpa,<br />
Swish Bush, Running Postman then<br />
Verticordia densiflora. Foxtail Mulga<br />
Grass occurred at 25-50 % cover in<br />
two plots and 1-5 % in the third.<br />
Clustered Lovegrass had not<br />
germinated in any plots. All the<br />
controls (not seeded) had less than<br />
1 % cover of native species.<br />
Effectiveness in displacing<br />
annual weeds<br />
The same 6 -10 species of annual<br />
weeds occurred across all plots,<br />
seeded and not seeded. The most<br />
commonly occurring were Scarlet<br />
Pimpernel, Wild Oat, Blowfly Grass,<br />
Slender Suckling Clover, Slender<br />
Birds Foot Trefoil and Silver Grass<br />
(Vulpia species). Together they<br />
formed 100% cover in all the control<br />
(unseeded) plots. In the seeded<br />
plots, where native cover was<br />
established, the weeds were more<br />
scattered and less vigorous with<br />
reduced flowering and seed<br />
production.<br />
Management implications<br />
July 2002, two years later.<br />
• Although a cover of native<br />
species was established within<br />
two years at this site, the<br />
complete displacement of<br />
annual weeds is a longer-term<br />
project.<br />
• Direct seeding will need to be<br />
at a larger scale than the trial<br />
plots (2 m x 2 m).<br />
• Weed control in the winter<br />
season following sowing will<br />
need to be very intensive to<br />
ensure seedling establishment.<br />
• Establishment of native shrub<br />
cover along the disturbed edges<br />
will begin to reverse the cycle<br />
of degradation. It will prevent<br />
further weed encroachment<br />
into intact bushland and, over<br />
time, reduce resources required<br />
for weed control.<br />
This case study highlights the<br />
complexities of restoring degraded<br />
bushland edges where there are<br />
scattered regenerating natives<br />
among a diverse weed flora.<br />
61
62<br />
Chapter 5 Broadleaf Herbs, Sedges and Succulents<br />
Case Studies<br />
Case study 5.2 Preventing further spread of a recent invader – Holly-leafed Senecio<br />
(Senecio glastifolius)<br />
Holly-leafed Senecio, a tall perennial<br />
herb from the daisy family, occurs<br />
naturally in the Cape Region of<br />
South Africa. It was first recorded<br />
as naturalised in Western Australia<br />
in 1986 (Western Australian<br />
Herbarium 1998). Collected from<br />
the Mt Adelaide and Mt Clarence<br />
Nature Reserves in the south west<br />
town of Albany, Holly-leafed Senecio<br />
was apparently an escapee from a<br />
garden adjoining the reserve. A<br />
series of fires facilitated rapid<br />
expansion of the original infestation<br />
and slashing of fire breaks<br />
contributed to further spread of<br />
seed. Holly-leafed Senecio now<br />
occurs throughout much of the 260<br />
hectares of Jarrah (Eucalyptus<br />
marginata), Albany Blackbutt<br />
(Eucalyptus staeri), and Marri<br />
(Eucalyptus calophylla) woodlands,<br />
as well as Allocasuarina open<br />
woodland, in the reserves. In recent<br />
years infestations have also been<br />
found growing on coastal sands and<br />
loams up to 20 kilometres from the<br />
original infestation (Western<br />
Australian Herbarium 1998). Hollyleafed<br />
Senecio has the potential to<br />
become a major weed of natural<br />
areas around much of the south<br />
coast of Western Australia<br />
(Keighery 1999c).<br />
Senecio glastifolius (photograph Greg Keighery)<br />
Why is it such a successful<br />
weed?<br />
• Produces prolific amounts of<br />
viable, wind dispersed seed.<br />
• Some evidence of persistent<br />
soil seedbank.<br />
• Fire is a major mechanism for<br />
establishment and facilitates<br />
spread.<br />
• Soil disturbance also facilitates<br />
spread and establishment.<br />
(from Williams et al. 1999)<br />
Management<br />
The Mt Adelaide and Mt Clarence<br />
Nature Reserves are vested in the<br />
City of Albany. Until very recently<br />
few resources have been available<br />
for weed management in the<br />
Reserves. Although the original<br />
infestation of Holly-leafed Senecio<br />
threatened natural areas from<br />
Augusta to Albany and possibly<br />
beyond, it was never clear who was<br />
responsible for its eradication.<br />
Community volunteers initiated the<br />
first control programs.<br />
The following report comes<br />
from Karin Baker, Friends of<br />
Mt Adelaide and Mt Clarence<br />
Nature Reserves<br />
• 1998: Fire followed by good<br />
rains led to prolific germination<br />
of Holly-leafed Senecio on the<br />
north face of the saddle<br />
between Mt Adelaide and Mt<br />
Clarence. Many people who<br />
used the reserves for their<br />
daily walks started hand-pulling<br />
the plants and leaving them in<br />
the Reserves. (It was not known<br />
at this stage that they could<br />
form seeds after being pulled).<br />
Three community volunteers<br />
started a hand-removal<br />
program in a Casuarina open<br />
woodland area, where the<br />
thickest infestations occurred.<br />
• 1999: Holly-leafed Senecio was<br />
hand-removed from dense<br />
thickets of Acacia pulchella up<br />
to 700 mm high. Hand-pulling in<br />
this area required thick gloves<br />
and trousers. Some of the Hollyleafed<br />
Senecio removed was<br />
two and a half metres tall. This<br />
time the plants were removed<br />
from the site. We were learning!<br />
• John Moore and Dale Baker, a<br />
board member of the first CRC<br />
(Cooperative Research Centre)<br />
for Weed Management Systems<br />
ran a series of herbicide trials.<br />
Lontrel at 500 mL/ha applied<br />
from a backpack mister in<br />
spring was found to be effective<br />
on the Holly-leafed Senecio and<br />
caused little damage to the<br />
native species in the area.<br />
• The CRC for <strong>Weeds</strong> and the<br />
Department of Agriculture,<br />
Western Australia held the<br />
state launch of ‘Weedbuster<br />
Week’ at the Mt Adelaide and<br />
Mt Clarence Reserves in<br />
October. Over 100 people<br />
turned up to hand-pull Hollyleafed<br />
Senecio and the ‘Friends<br />
of Mt Adelaide & Mt Clarence<br />
Reserves’ was formed. The<br />
following year the Bushcarers<br />
Group, an umbrella group for<br />
all the Friends groups that were<br />
starting up around the city was<br />
formed.<br />
• Following on from the work<br />
day, populations were sprayed<br />
with Lontrel (500 mL/ha).
Chapter 5 Broadleaf Herbs, Sedges and Succulents<br />
Case Studies<br />
• Further spot fires in the<br />
following years have produced<br />
a germination of Holly-leafed<br />
Senecio. These have been dealt<br />
with as quickly as time and<br />
labour allow. Green Corps<br />
teams have been used but are<br />
not usually available at the time<br />
they are most needed.<br />
• Outcome: Areas where there<br />
is a good cover of natural<br />
vegetation have had very little<br />
Holly-leafed Senecio growing in<br />
the following years. However,<br />
along slashed firebreaks and<br />
under power lines, germination<br />
occurs every year. Outbreaks<br />
should be sprayed or hand -<br />
pulled in the first year following<br />
fire, to stop the spread of seed.<br />
• Being wind dispersed, there is<br />
probably seed all over the<br />
reserves, and any fire will result<br />
in further outbreaks.<br />
Case study 5.3<br />
As well as 260 hectares of the<br />
nature reserves to deal with,<br />
outlying populations also needed to<br />
be covered as a priority and<br />
resources were limited.<br />
In 2000, Holly-leafed Senecio was<br />
placed on the ‘Alert List for<br />
<strong>Environmental</strong> <strong>Weeds</strong>’ – weeds<br />
identified by Environment Australia<br />
as likely to be a significant threat to<br />
biodiversity. Grants to undertake onground<br />
actions to manage/control<br />
isolated populations of weeds listed<br />
became available. The objective was<br />
to prevent further establishment<br />
and expansion of listed weeds.<br />
The Department of Agriculture,<br />
Western Australia, City of Albany<br />
and Albany Bushcarers jointly<br />
applied for funding to have the<br />
current distribution of the Hollyleafed<br />
Senecio mapped and to<br />
implement a carefully targeted<br />
control program. They were<br />
successful and work will begin in<br />
spring 2002.<br />
The case study is an example of<br />
community, federal, state and local<br />
government working together to<br />
acquire resources and to<br />
implement effective on-ground<br />
management of weeds invading<br />
natural areas. With any one of the<br />
parties not present, the work<br />
would not be possible. It also<br />
highlights, again, the importance of<br />
early intervention and eradication<br />
of small infestations of new weeds.<br />
Source: Information for the case<br />
study was provided by Karin Baker,<br />
(Friend of Mt Adelaide & Mt<br />
Clarence Reserves), Greg Keighery<br />
(DCLM), John Moore (Western<br />
Australian Department of<br />
Agriculture, Albany) and Ryan<br />
Munro (City of Albany).<br />
Geraldton Carnation Weed (Euphorbia terracina) – managing the spread of a serious invader<br />
Geraldton Carnation Weed has<br />
been slowly spreading south and<br />
east over the last 60 years and<br />
habitats at risk include bushlands<br />
of the offshore islands and<br />
calcareous (limestone) plant<br />
communities throughout southern<br />
Western Australia (Keighery and<br />
Keighery 2000).<br />
Reproductive biology,<br />
dispersal and spread<br />
• Short-lived perennial herb to<br />
one metre.<br />
• Loses leaves and dies back to a<br />
stem in summer, reshooting<br />
with the first autumn rains.<br />
• Often but not always killed by<br />
fire.<br />
• Regenerates from soil-stored<br />
seed. Seed remains viable in<br />
the soil for at least 3-5 years.<br />
Bulk of seed germinates with<br />
onset of autumn rains but will<br />
germinate after good summer<br />
rains.<br />
• Seed released explosively<br />
from fruits.<br />
• Water, soil movement, birds<br />
(particularly feral doves), and<br />
possibly ants play a role in<br />
dispersal. Often introduced<br />
into bushland with crushed<br />
limestone material brought in<br />
for paths.<br />
• Is increasing on roadsides and<br />
highways. Soil movement and<br />
road maintenance machinery<br />
are one of the major<br />
mechanisms for long distance<br />
dispersal.<br />
(Source: Keighery and Keighery<br />
2000, Randall and Brooks 2000,<br />
Parsons and Cuthbertson 2001).<br />
Impacts<br />
In Western Australia Geraldton<br />
Carnation Weed can be found<br />
invading natural ecosystems from<br />
Geraldton to Cape Arid. It has been<br />
recorded in coastal dune heath,<br />
limestone heath, Tuart woodland,<br />
Banksia woodland and ephemeral<br />
wetlands. Once established it is<br />
able to invade relatively<br />
undisturbed bushland. It is a<br />
particularly serious weed of Tuart<br />
woodlands and one of the few<br />
serious weeds of coastal heath in<br />
south west Western Australia<br />
(Keighery and Keighery 2000).<br />
Control and Management in<br />
Kings Park<br />
Geraldton Carnation Weed is<br />
invading Kings Park Banksia<br />
woodlands in four main locations.<br />
Management has effectively<br />
focused on preventing spread<br />
through the identification and<br />
eradication of new outbreaks.<br />
• Volunteers and contractors are<br />
able to accurately identify the<br />
weed and new outbreaks are<br />
mapped as soon as located.<br />
• Large infestations are initially<br />
spot sprayed with herbicide<br />
Brush-off ® (1 g/150 L) or<br />
Brush-off ® + glyphosate.<br />
Follow-up includes regular<br />
inspection of the site and<br />
hand-removal of remaining<br />
plants. This continues for at<br />
least five years.<br />
Note: The entire plant must be removed.<br />
Plants as young as three weeks will resprout<br />
from any root material left behind.<br />
63
64<br />
Chapter 5 Broadleaf Herbs, Sedges and Succulents<br />
Case Studies<br />
Euphorbia terracina invading the understorey of Tuart woodland at Bold Park.<br />
Case study 5.4 Typha orientalis – an aggressive coloniser of wetlands<br />
Two species of Typha are known<br />
from Western Australia,<br />
T. domingensis and T. orientalis.<br />
Native to eastern Australia,<br />
T. orientalis is thought to be<br />
introduced in Western Australia and<br />
it is an aggressive coloniser of<br />
wetlands of the Swan Coastal Plain<br />
and Jarrah Forest. Typha<br />
domingensis is native and occurs<br />
only occasionally in the region. The<br />
native and the weed can be difficult<br />
to tell apart.<br />
Typha domingensis has a<br />
leaf blade that does not<br />
exceed 8 mm in width<br />
and a cinnamon brown<br />
female flower spike that<br />
is 5 to 20 mm in diameter<br />
and 6 to 20 times as long<br />
as it is wide.<br />
Typha orientalis has a leaf<br />
blade up to 14 mm wide<br />
with a chestnut brown<br />
female flower that is 10 to<br />
30 mm in diameter and 5<br />
to 10 times as long as it is<br />
wide. Intermediates exist<br />
and expert help is<br />
sometimes required for<br />
identification.<br />
Life-cycle and Reproductive<br />
Biology of Typha orientalis<br />
• Expansion of existing<br />
populations is rapid, occurring<br />
via rhizomes that grow out<br />
from the population each<br />
season. Establishment of new<br />
populations is via seed.<br />
• Typha orientalis can produce<br />
220,000 seed per flower head.<br />
The seed is very light and winddispersed,<br />
often over several<br />
kilometres. Seed also spreads<br />
via water and is moved around<br />
in mud on the feet of birds,<br />
livestock and humans.<br />
• Seed germination generally takes<br />
place from December to April.<br />
• High temperatures (above<br />
20° C) and high levels of light<br />
are required for germination.<br />
Seeds germinate in mud on the<br />
margins of waterways and,<br />
sometimes, under water (less<br />
than eight centimetres deep).<br />
• Once established, seedlings<br />
start producing rhizomes and<br />
the diameter of the plant can<br />
extend to three metres within<br />
the first year.<br />
The program has resulted in a<br />
significant reduction of Geraldton<br />
Carnation Weed invading the<br />
bushland in Kings Park.<br />
Effective management has relied on:<br />
• Recognising, recording and<br />
removing new infestations.<br />
• Revisiting known populations<br />
year after year (for at least five<br />
years) following up previous<br />
work.<br />
(From Dixon 2000)<br />
Cautionary note: The sap in the stems of<br />
Euphorbia terracina is highly caustic and<br />
can cause quite dramatic and painful<br />
inflammations of sensitive skin. If the sap<br />
gets into the eyes temporary blindness is<br />
often reported and in some severe cases<br />
varying vision loss has been reported. When<br />
working with this plant, or any Euphorbia,<br />
care should be taken to minimise direct<br />
contact with the plant. Safety glasses or face<br />
shields and gloves, at a minimum, with fully<br />
enclosed shoes and neck to wrist to ankle<br />
protection is advised.<br />
• Active growth is mainly<br />
through summer and autumn<br />
although in mild climates it can<br />
occur at any time of the year.<br />
• Flowering commences in early<br />
summer and seed is dispersed<br />
from December onwards.<br />
(from Parsons and Cuthbertson 2001)<br />
Establishment and spread of<br />
Typha orientalis at Lake<br />
Forrestdale<br />
A study based on a series of aerial<br />
photographs of Lake Forrestdale<br />
just south of Perth illustrates how<br />
quickly the weed can spread once<br />
established at a site (Watkins and<br />
McNee 1985). The aerial photos<br />
revealed that prior to 1964 no<br />
T. orientalis occurred at the lake,<br />
with the first stand appearing in<br />
1967. By 1976 a fairly large stand<br />
had established on the southern<br />
end of the lake and by 1984<br />
T. orientalis had colonised almost<br />
the entire six kilometres of lake<br />
margin. Dense colonies had in many<br />
places displaced the native rushes<br />
and sedges in the understorey of<br />
the Melaleuca woodland fringing the
Chapter 5 Broadleaf Herbs, Sedges and Succulents<br />
Case Studies<br />
lake. Seed had been responsible<br />
for the establishment of new<br />
populations but existing<br />
populations had also been<br />
expanding rapidly over that time<br />
(Watkins and McNee 1985).<br />
Control of Typha<br />
Preventing establishment of<br />
seedlings is vital to limiting spread<br />
of the weed. Trials at Lake<br />
Forrestdale found cultivating<br />
seedling populations late in<br />
autumn, when most seed has<br />
germinated, effectively prevented<br />
seedling establishment. Although<br />
water levels are at their lowest at<br />
this time in Perth, the ground was<br />
still soft. A Honda trike with<br />
balloon tyres dragging a piece of<br />
weld mesh was used to cultivate<br />
the population (Watkins and<br />
McNee 1985).<br />
Maintaining a cover of native<br />
species in fringing vegetation will<br />
keep light levels down and prevent<br />
germination of seeds. Juncus<br />
species will displace seedlings.<br />
Cutting shoots 15 cm below the<br />
water surface two to three times in<br />
one season when plants are<br />
actively growing, but before seeds<br />
are fully formed, can reduce a<br />
stand by 95-99 % (Motivans and<br />
Apfelbaum 2002).<br />
Plants generally resprout following<br />
fire unless fire kills rhizomes. Case<br />
studies looking at control through<br />
burning (low intensity) dense<br />
infestations of Typha species in<br />
North America, in late winter, have<br />
shown that under certain<br />
conditions a 70 % reduction in<br />
populations can be achieved<br />
(Snyder 1993).<br />
As Typha often grows in water,<br />
chemical application is sometimes<br />
inappropriate. Roundup Biactive<br />
(360 g/L) at 13 mL/L is registered<br />
for use on Typha species in<br />
Tasmania. Apply in the period<br />
between male flowers opening, and<br />
six weeks after female flowers<br />
emerge. Avoid producing run-off or<br />
spray drift (DPIWE 2001).<br />
Typha orientalis is an<br />
aggressive coloniser of<br />
wetlands on the Swan<br />
Coastal Plain. Effective<br />
management requires an<br />
integrated approach<br />
• Keeping disturbance out of<br />
intact plant communities<br />
prevents establishment of<br />
seedlings.<br />
• Controlling seedlings as a<br />
priority prevents establishment<br />
of new populations.<br />
• Removing emerging flower<br />
spikes from established<br />
populations limits seed<br />
production and spread.<br />
• Using both physical and<br />
chemical techniques is<br />
essential for effective control<br />
of established populations.<br />
Rhizome of Typha orientalis<br />
65
Chapter 5 Annual Broadleaf Herbs, Sedges and Succulents Weed Management Table<br />
66<br />
Species Common name Timing of seed germination Growing<br />
season<br />
Arctotheca<br />
calendula<br />
Bellardia<br />
trixago<br />
Cakile<br />
maritima<br />
Flowers Dispersal agent Seedbank<br />
persistence (years)<br />
Cape Weed after rains win/spr Aug-Nov wind some dormancy 8+? y<br />
White Bartsia autumn/winter win/spr Sep-Jan wind<br />
Sea Rocket mostly spring but any time after<br />
rain<br />
Can be<br />
biennial<br />
win/spr Jan-Dec wind, water 2+ y<br />
Carduus Slender Thistle<br />
pycnocephalus<br />
up to 6wks after autumn rains win/spr Oct-Dec wind, water, birds 10+<br />
Carduus<br />
tenuiflorus<br />
Carthamus<br />
lanatus<br />
Centranthus<br />
macrosiphon<br />
Chenopodium<br />
album<br />
Cirsium<br />
vulgare<br />
Sheep Thistle up to 6wks after autumn rains win/spr Sep-Nov wind, water, birds 10+<br />
Saffron Thistle autumn and early winter.<br />
staggered south west W.A<br />
win/spr Dec-Apr water, adhesion 8<br />
Pretty Betsy win/spr Aug-Nov limestone gravel, wind? short?<br />
Fat Hen after rains all year Mar-Apr/Oct-<br />
Dec<br />
birds, machinery 20-40<br />
Spear Thistle autumn mostly win/spr Jan-Dec wind, water, machinery 30+ y<br />
Conyza albida Tall Fleabane autumn/winter/spring win/spr Dec-Feb wind<br />
Conyza<br />
bonariensis<br />
Crepis<br />
capillaris<br />
Flaxleaf<br />
Fleabane<br />
Smooth Hawks<br />
Beard<br />
Crepis foetida Stinking Hawks<br />
Beard<br />
Cucumis<br />
myriocarpus<br />
Dischisma<br />
arenarium<br />
Dischisma<br />
capitatum<br />
Dittrichia<br />
graveolens<br />
Echium<br />
plantagineum<br />
Prickly Paddy<br />
Melon<br />
autumn/winter/spring win/spr Dec-Feb wind<br />
win/spr Nov-Jan wind y<br />
win/spr Nov-Jan wind y<br />
sum Jan-May birds, machinery<br />
win/spr Aug-Nov<br />
Wolly Dischisma win/spr Aug-Sep<br />
Stinkwort sum Jan-Apr wind, animal<br />
Patersons Curse all year win/spr Sep-Jan water, machinery 6 (most in 2) y<br />
Emex australis Doublegee all year win/spr Jul-Oct tyres, water, machinery 4+<br />
Erodium botrys Long Storksbill mainly autumn/winter but spring/<br />
summer if moisture is available<br />
Euphorbia<br />
peplus<br />
Fumaria<br />
capreolata<br />
Fumaria<br />
muralis<br />
Hypochaeris<br />
glabra<br />
Hypochaeris<br />
radicata<br />
Petty Spurge autumn to spring win/spr Jul-Jan<br />
Climbing<br />
Fumitory<br />
autumn to spring win/spr Aug-Nov<br />
win/spr Aug-Nov 3+<br />
Wall Fumitory autumn to spring win/spr Jun-Dec 20+<br />
Flat Weed autumn/winter win/spr Jan-Dec wind y<br />
autumn win/spr Jan-Dec wind
Chapter 5 Annual Broadleaf Herbs, Sedges and Succulents Weed Management Table<br />
Suggested methods of management and control Similar natives<br />
often mistaken<br />
for weeds<br />
Colonises bare soil and disturbed sites. Lontrel ® 6 mL/10 L (300 mL/ha) in early growth stages. Glyphosate 0.2 % will control<br />
at all growth stages.<br />
Reference<br />
146, 53, 96, 115, 101,<br />
167, 242, 222<br />
Colonises disturbed wetlands. Hand remove isolated plants before seed set. Spot spray 0.2 % glyphosate. 167, 242, 222<br />
300, 207, 167, 242<br />
Seedlings establish in bare open ground so establish desirable vegetation cover. Hand remove isolated plants through spring<br />
and early summer. Glyphosate applied with a rope wick provides good control or spot spray Lontrel®10 ® mL in 10 L water<br />
+ 25 mL wetting agent. Control at rosette stage.<br />
300, 248, 91, 121, 228,<br />
167, 242<br />
as for Slender Thistle 300, 248, 91, 228, 167,<br />
242<br />
as for Slender Thistle 300, 248, 96, 147, 251,<br />
145, 120, 228, 167, 242<br />
Hand remove small populations. Spray metsulfuron methyl 0.1 g/15 L (2 g/ha) + wetting agent. 300, 101, 167, 242<br />
Highly susceptible to mowing before flowering. Requires bare ground for establishment and persistence. Herbicide application<br />
most effective in early growth stages.<br />
Seedlings establish in bare open ground so establish desirable vegetation cover. Glyphosate 0.5 % provides effective control of<br />
seedling and adult plants or Lontrel® ® 6 mL/10 L (300 ml/ha) + wetting agent, rosette to early flowering.<br />
Does not compete well under high plant density or cover. Requires disturbance to establish and persist. Establish desirable<br />
vegetation.<br />
Does not compete well under high plant density or cover. Requires disturbance to establish and persist. Establish desirable<br />
vegetation.<br />
19, 228, 167, 242<br />
248, 96, 167, 242, 222<br />
333, 325, 167, 242<br />
300, 333, 325, 167, 242<br />
Spot spray 1 % glyphosate + Pulse®or ® 10 mL Lontrel® ® in 10 L of water + 25 mL Pulse ® . 167, 242, 222<br />
Spot spray 1 % glyphosate + Pulse®or ® 10 mL Lontrel® ® in 10 L of water + 25 mL Pulse®. ®<br />
300, 167, 242, 222<br />
Hand remove isolated plants before flowering. Not killed by glyphosate. Spot spray 2 mL Garlon®in ® 10 L of water + 25 mL<br />
wetting agent.<br />
Spot spray 0.2 % glyphosate. 167, 242<br />
Spot spray 0.2 % glyphosate. 167, 242<br />
248, 167, 242, 222<br />
Hand remove isolated plants before flowering. Slash very close to ground (can resprout). 248, 167, 242<br />
Slashing or mowing can cause out of season flowering and seed production. Spot spray in late autumn when most seed has<br />
germinated for the year with 0.5g/10 L chlorsulfuron + wetting agent-this will help prevent further germination. Glyphosate will<br />
control existingplants. Spot spray plants with 1 % Grazon®. ®<br />
Seed produced at early stage. Any control program must aim at killing all plants shortly<br />
after emergence and must continue for a number of years. Spot spray with glyphosate 0.5-0.7 % to kill existing plants but bare<br />
soil quickly reinfested.<br />
Lontrel®at ® 6 mL/10 L (300 mL/ha) + wetting agent applied before flowering or Verdict 520® ® at 1.5 mL/ 10 L (75 mL/ha) +<br />
wetting agent.<br />
229, 248, 96, 257, 167,<br />
242, 222<br />
133, 248, 286, 167, 242,<br />
222<br />
E. cygnorum 12, 228, 222, 101, 167,<br />
242, 222<br />
Colonises degraded sites; spray metsulfuron methyl 0.1 g/15 L (2.5 g/ha) + wetting agent or glyphosate 0.5 %. 101, 167, 242<br />
Colonises degraded sites; spray metsulfuron methyl 0.1 g/15 L (2.5 g/ha) + wetting agent or glyphosate 0.5 %. 101, 167, 242<br />
Colonises degraded sites; spray metsulfuron methyl 0.1 g/15 L (2.5 g/ha) + wetting agent or glyphosate 0.5 %. 254, 62, 101, 167, 242<br />
Rosettes wiped with glyphosate 30 % provides effective control. Dense infestations - 25 mL wetting agent + 10 mL Lontrel®in ®<br />
10 L of water.<br />
Rosettes wiped with glyphosate 30 % provides effective control. Dense infestations - 25 mL wetting agent + 10 mL Lontrel®in ®<br />
10 L of water.<br />
300, 228, 222, 167, 242<br />
300, 54, 228, 167, 242<br />
167, 242<br />
67
Chapter 5 Annual Broadleaf Herbs, Sedges and Succulents Weed Management Table<br />
68<br />
Species Common name Timing of seed germination Growing<br />
season<br />
Lactuca<br />
serriola<br />
Lupinus<br />
angustifolius<br />
Lupinus<br />
cosentinii<br />
Malva<br />
parviflora<br />
Medicago<br />
polymorpha<br />
Melilotus<br />
indicus<br />
Mesembryanthemum<br />
crystallinum Osteospermum<br />
clandestinum<br />
Parentucellia<br />
viscosa<br />
Petrorhagia<br />
velutina<br />
Portulaca<br />
oleracea<br />
Ranunculus<br />
muricatus<br />
Raphanus<br />
raphanistrum<br />
Senecio<br />
elegans<br />
Senecio<br />
vulgaris<br />
Prickly Lettuce autumn to spring sum Oct-Feb wind y<br />
Narrowleaf<br />
Lupin<br />
Sand Plain<br />
Lupin<br />
Small Flowered<br />
Mallow<br />
autumn/winter win/spr Jul-Nov little dormancy<br />
autumn win/spr Aug-Nov some dormancy<br />
spring to autumn win/spr Jul-Nov soil, water 100? y<br />
Burr Medic autumn/winter win/spr May-Nov animal, adhesion 5+<br />
King Island<br />
Meliot<br />
Common Ice<br />
Plant<br />
win/spr Aug-May water, wind 20+? y<br />
autumn/winter or after rains win/spr Sep fleshy fruit-animal ingestion 22? y<br />
Stinking Roger autumn/winter win/spr Oct-Dec wind<br />
Sticky Bartsia win/spr Aug-Jan wind, water, machinery<br />
Velvet Pink win/spr Aug-Dec<br />
Pigweed most in autumn sum Feb-May wind, water, soil, birds 40<br />
Sharp Buttercup win/spr Aug-Dec<br />
Wild Radish bulk after autumn rains but<br />
sporadic throughout year<br />
all year Apr-Nov wind, water, machinery 20 y<br />
win/spr Sep-Mar wind<br />
Groundsel all year win/spr Jul-Feb wind 5<br />
Silene gallica French Catchfly win/spr Jul-Dec<br />
Solanum<br />
americanum<br />
Solanum<br />
nigrum<br />
Glossy<br />
Nightshade<br />
Black<br />
Nightshade<br />
Sonchus asper Prickly<br />
Sowthistle<br />
Sonchus<br />
oleraceus<br />
Symphyotrichum<br />
subulatum<br />
Tribulus<br />
terrestris<br />
win/spr Mar-Dec birds, water, soil, machinery<br />
spring/summer win/spr Jan-Dec birds, water, soil, machinery 5+ y<br />
all year win/spr Sep-Dec wind 1-2 y<br />
Sowthistle autumn/winter win/spr Sep-Dec wind 1-2 y<br />
Bushy Starwort sum Dec-Mar wind<br />
Caltrop all year all year Jan-Dec tyres, water, machinery several<br />
Trifolium spp Clovers win/spr Sep-Dec soil, water some dormancy<br />
Ursinia<br />
anthemoides<br />
Flowers Dispersal agent Seedbank<br />
persistence (years)<br />
Ursinia win/spr Jul-Dec wind, adhesion<br />
Vicia sativa Common Vetch autumn/winter win/spr Jul-Dec birds, horses, sheep ingest some dormancy<br />
Can be<br />
biennial
Chapter 5 Annual Broadleaf Herbs, Sedges and Succulents Weed Management Table<br />
Suggested methods of management and control Similar natives<br />
often mistaken<br />
for weeds<br />
Colonises disturbed wetland sites. 316, 167, 242<br />
Hand remove scattered plants. Spray dense infestations metsulfuron-methyl 0.1 g/15 L (2-3 g/ha) + wetting agent or<br />
Lontrel® ® 6 mL/10 L (300 mL/ha) + wetting agent to late flowering (will prevent seed set).<br />
101, 222, 167, 242<br />
Hand remove scattered plants. Spray dense infestations metsulfuron-methyl 0.1g/15 L (2-3 g/ha) + wetting agent. 258, 101, 222, 167, 242<br />
Hand remove isolated plants. Chemical control only effective at early growth stages. M. australiana 197, 222, 167, 242,<br />
25 mL of wetting agent + 10 mL of Lontrel® ® in 10 L of water provides effective control in early winteror<br />
metsulfuron methyl 0.1 g/10 L + wetting agent.<br />
200, 228, 167, 242<br />
Weed of highly disturbed bushland. If slashing cut below lowest branch axil to prevent resprouting. 300, 335, 167, 242<br />
Hand remove isolated plants through spring and early summer. Spot spray with 0.5 % glyphosate or Lontrel® ® 10 mL/ 10 L<br />
(500 mL/ha).<br />
334, 316, 167, 242, 222<br />
Spot spray with glyphosate 0.5 % before flowering. 222, 167, 242, 222<br />
Spot spray with glyphosate 0.5 % before flowering. 167, 242, 222<br />
Hand remove before flowering. Will shoot from stem fragments under moist conditions. Spot spray 0.5 % glyphosate. 217, 167, 242, 222<br />
Weed of highly disturbed edges. Hand remove isolated plants several times over the year. Spot spray 1% glyphosate before<br />
flowering.<br />
Only persists in disturbed sites. Lontrel® ® at 10 mL in 10 L of water + 25 mL wetting agent applied before stem elongation in<br />
late spring.<br />
Only persists in disturbed sites. Lontrel® ® at 10 mL in 10 L of water + 25 mL wetting agent applied before stem elongation in<br />
late spring.<br />
167, 242<br />
R. amphitrichus, 167, 242<br />
R. colonorum<br />
248, 66, 228, 167, 242<br />
30, 167, 242, 222<br />
300, 337, 167, 242, 222<br />
167, 242<br />
Weed of disturbed sites. Shade reduces seed production. Hand weed small infestations. 300, 167, 242<br />
<strong>Weeds</strong> of disturbed sites. Shade reduces seed production. Hand weed small infestations. 300, 141, 167, 242<br />
Slashing often ineffective as flowers continue to be produced. Rosette stage preferred time for effective chemical control.<br />
Lontrel® ® at 10 mL in 10 L of water + 25 mL wetting agent.<br />
Slashing often ineffective as flowers continue to be produced. Rosette stage preferred time for effective chemical control.<br />
Lontrel® ® at 10 mL in 10 L of water + 25 mL wetting agent.<br />
S.hydrophilus<br />
Native<br />
Sowthistle<br />
Colonises disturbed wetlands. Hand remove isolated plants before seed set. 167, 242<br />
Glyphosate 1 % effective on seedlings. Exclude people and close tracks to stop spread. On bare tracks diesel can be used to kill<br />
plants and penetrate and destroy seed in surface soil.<br />
Hand remove isolated plants before flowering. Spot spraying Lontrel® ® 10 mL/10 L + wetting agent in early winter before<br />
flowering provides effective control.<br />
Colonises bare disturbed sites. Can smother native plants. Lontrel® ® 10 mL/10 L + wetting agent provides effective control in<br />
early growth stages or metsulfuron methyl 0.1 g/ 10 L + wetting agent.<br />
300, 11, 168, 167, 242,<br />
222<br />
300, 11, 168, 167, 242,<br />
222<br />
248, 167, 242<br />
228, 167, 242<br />
167, 242<br />
Reference<br />
1, 228, 222, 167, 242,<br />
222<br />
69
Chapter 5 Perennial Broadleaf Herbs, Sedges and Succulents Weed Management Table<br />
70<br />
Species Common name Flowering Reproductive unit Seedbank persistence<br />
(years)<br />
Dispersal agent<br />
Acetosella vulgaris Sorrel Aug-Dec seed, root fragment long wind, water, animal, soil<br />
Agapanthus praecox Agapanthus Oct-Dec rhizome, seed short soil<br />
Agave americana Century Plant Dec-Jan seed, suckers wind, water<br />
Alternanthera pungens Khaki Weed Mar-Jul stem and root fragment, seed many soil, animal (adhesion)<br />
Arctotheca populifolia Dune Arctotheca Jun-Jan seed wind, soil<br />
Arctotis stoechadifolia Arctotis Sep-Jan root fragment germination of seed rare soil<br />
Argyranthemum frutescens Marguerite Jul-Oct seed<br />
Asphodelus fistulosus Onion Weed Jun-Oct seed many wind, machinery, water<br />
Berkheya rigida African Thistle Oct-May seed, stem and root fragments many adhesion, soil<br />
Canna x generalis Canna Lily Nov-Mar rhizome, seed? soil, bird<br />
Carex divisa Divided Sedge Sep-Dec seed? water?<br />
Carpobrotus aequilaterus Angular Pigface Aug-Nov seed, stem fragments<br />
Carpobrotus edulis Pigface Aug-Nov seed, stem fragments 2 + rabbits, birds (ingestion)<br />
Centranthus ruber Red Valerian Oct-Mar seed, rhizome soil<br />
Chenopodium ambrosioides Mexican Tea Mar-Jul seed soil, machinery, water<br />
Cyperus congestus Dense Flat Sedge Jul-Oct<br />
Cyperus eragrostis Umbrella Sedge Jun-Jul seed, rhizome soil, water<br />
Cyperus polystachyos Bunchy Sedge Dec-Jul<br />
Cyperus rotundus Nut Grass Apr-Jul seed, tubers, rhizome seed viability low, tubers<br />
longevity up to 10<br />
soil, water (flooding), wind<br />
Epilobium ciliatum Willow Herb Oct-Jan seed, crown fragments short? wind, soil<br />
Euphorbia paralias Sea Spurge Oct-Jun seed, root fragments 2 + in salt water explosive, water, sand, wind<br />
Euphorbia terracina Geraldton Carnation<br />
Weed<br />
Aug-Dec seed 3-5 explosive, birds, ants, limestone,<br />
machinery<br />
Foeniculum vulgare Fennel Jul-Jan root fragments, seed soil, machinery ,water<br />
Hypericum perforatum St John Wort Mar-0ct stem fragments, seed, rhizome 10 water, soil, machinery, animals<br />
(adhesion and ingestion)<br />
Isolepis prolifera Budding Club Rush Oct-Jan seed? stem fragments water<br />
Juncus acutus Spiny Rush Oct-Dec seed, crown fragments water, machinery<br />
Juncus microcephalus Nov-Feb seed water, machinery<br />
Limonium companyonis Statice, Sea Lavender Nov-Feb seed<br />
Limonium sinuatum Statice, Sea Lavender Sep-May seed<br />
Lotus uliginosus Greater Lotus Nov-Mar seed, rhizome water, soil<br />
Reproductive unit: bold=main mechanism of dispersal. Seedbank perisistence: long=5+ years short= months to 1 year
Chapter 5 Perennial Broadleaf Herbs, Sedges and Succulents Weed Management Table<br />
Some suggested methods of management and control Similar natives often<br />
mistaken for weeds<br />
Reference<br />
Spot spray with 0.5 % glyphosate or metsulfuron methyl 0.2 g/10 L + 25 mL Pulse ® . 248, 21, 228, 167,<br />
242<br />
Dig out taking care to remove all bulbs. Remove and burn or deep bury flower heads to stop spread of seed. Spray with 1 % Grazon ® just<br />
before flowering.<br />
21, 101, 167, 242<br />
Dig out small infestations. Stem inject into base of leaves 1 partTordon ® / 5 parts diesel. (flowers only once, after 10 to 15 years, then dies) 21, 167, 242<br />
Difficult to control as it is a true deep-rooted perennial. Cut roots well below surface. Cultivation can spread plant fragments. Spot spray<br />
with 1 % glyphosate before flowering.<br />
Difficult to hand pull and resistant to chemicals, it is short-lived. Lontrel® ® 10 mL/10 L (500 mL/ha) + Pulse ® in early growth stages.<br />
Glyphosate 1% will control at all growth stages.<br />
A. nodiflora 248, 222, 167, 242<br />
143, 102, 167, 242,<br />
222<br />
30, 167, 242<br />
Hand pull small infestations. 143, 102, 167, 242,<br />
Hand pull small infestations. Metsulfuron-methyl 0.1 g /10 L +100 mL spray oil when flowering. 248, 228, 167, 242<br />
Dig out and destroy single plants before flowering. Suggest Lontrel ® 10 mL/10 L + wetting agent at early rosette stage or 0.5 % glyphosate. 30, 248, 222, 167,<br />
242<br />
Hand pull small infestations. Cut stems to ground level, paint 10 % glyphosate on larger infestations. 241, 167, 242<br />
Physical control where only scattered plants occur. Try 1 % glyphosate. 167, 242, 222<br />
As for C. edulis? C. virescens 167, 242<br />
Roll up large mats removing all roots (shallow-rooted) and stem fragments. Follow up with removal of any germinating plants. Spray with<br />
glyphosate at label rates.<br />
13, 83, 84, 167, 242<br />
Suggest metsulfuron methyl 0.15 g/10 L (5 g/ha) + Pulse ® before flowering. 300, 101, 167, 242<br />
Hand remove small populations (use gloves); Suggest metsulfuron methyl 0.7 g/10 L (20 g/ha) + Pulse ® before flowering or<br />
1 % glyphosate + Pulse ® .<br />
102, 167, 242<br />
Try 1 % glyphosate + Pulse ® . 167, 242, 222<br />
Try 1 % glyphosate + Pulse ® . 167, 242, 222<br />
Try 1 % glyphosate + Pulse ® . 167, 242, 222<br />
Intolerant of dense shade - apply glyphosate at label rate before the fifth leaf stage after this time herbicide is not translocated to tubers.<br />
Difficult to control.<br />
Spray seedlings with glyphosate; established plants will resprout from crown after glyphosate treatment. Seedlings normally only establish<br />
on bare moist soil.<br />
E. billardiereanum,<br />
E. hirtigerum<br />
332, 248, 241, 317,<br />
167, 242<br />
248, 96, 167, 242<br />
Hand remove small isolated infestations. Long tap root. Consider possible dune erosion. 248, 330, 167, 242<br />
Large infestations - spot spray- with herbicide metsulfuron methyl 0.1 g/15 L or metsulfuron methyl + 1 % glyphosate before flowering.<br />
Follow-up with hand removal for at least five years.<br />
Usually found in very disturbed sites; persistent and difficult to eradicate. Spot spray with 1.5 % glyphosate or metsulfuron methyl<br />
0.7 g/10 L (20 g/ha) + Pulse ® . On older plants apply just before flowering. Follow up on seedlings. Seed germinates throughout year;<br />
plants don't flower until around 2 years.<br />
Seedlings establishment restricted by soil cover, litter and competition. Spot spray at flowering (50 % bud - 50 % open flowering - do not<br />
spray after 50 % green bud) with Grazon® ® (triclopyr + picloram) at label rates. Biological control available from CSIRO.<br />
Establish native vegetation cover; dig out isolated plants; spray 2 % glyphosate-repeat application six weeks later. Burning plants after<br />
they have been knocked back by herbicide increases kill rate. Consider possibility of erosion.<br />
98, 173, 267, 248,<br />
167, 242<br />
23, 102, 167, 242<br />
55, 56, 8, 341, 57,<br />
167, 242<br />
167<br />
6, 241, 248, 167,<br />
242<br />
Dig out isolated plants. J. holoschoenus 167, 242<br />
Hand remove small patches. 167, 242<br />
248, 167, 242<br />
Weed of highly disturbed areas. Spot spray Lontrel ® at 10 mL/10 L + 25 mL wetting agent. 101, 228, 167, 242<br />
71
Chapter 5 Perennial Broadleaf Herbs, Sedges and Succulents Weed Management Table<br />
72<br />
Species Common name Flowering Reproductive unit Seedbank persistence<br />
(years)<br />
Malva dendromorpha Tree Mallow Aug-Dec seed long birds-(adhesion and ingestion)<br />
Myosotis sylvatica Forget-Me-Not Sep-Dec seed animals (adhesion), soil<br />
Oenothera drummondii Beach Evening Primrose Feb-Jun seed O. biennis up to 80.<br />
Oenothera laciniata May-Jan seed<br />
Oenothera mollissima Nov-Mar seed<br />
Oenothera stricta Jan-Nov seed<br />
Dispersal agent<br />
Parietaria judaica Pellitory Dec-Jan seed, root fragments water, wind, soil, animals<br />
(adhesion), ants<br />
Pelargonium capitatum Rose Pelargonium Aug-Dec seed, root fragments wind, water, soil<br />
Phytolacca octandra Red Ink Plant Jan-Mar seed short birds (ingestion)<br />
Plantago lanceolata Ribwort Plantain Nov-mar seed, stem fragments some dormancy soil, water<br />
Plantago major Greater Plantain Oct-Feb seed up to 40 soil, water<br />
Rumex brownii Swamp Dock Apr-May seed, root fragments 80+ (some species) animals, soil, machinery<br />
Rumex conglomeratus Clustered Dock Oct-Feb seed, root fragments long animals, soil, machinery<br />
Rumex crispus Curled Dock Jul-Dec seed, root fragments 20+ animals, soil, machinery<br />
Sagina procumbens Spreading Pearlwort Jul-Sep seed, stem and root fragments long probably wind<br />
Senecio glastifolius Holly-leafed Senecio Aug-Oct seed some persistence wind, soil, machinery<br />
Trachyandra divaricata Dune Onion Weed Aug-Nov seed light induces dormancy wind<br />
Trifolium repens White Clover Jul-Jan seed, stem fragments, stolons 25+ wind, water, birds, animal<br />
(ingestion)<br />
Typha orientalis Typha Oct-Dec seed, rhizomes wind, water, soil<br />
Vinca major Blue Periwinkle Aug-Nov stem fragments, stolons Seed rarely matures soil, machinery, water?<br />
Reproductive unit: bold=main mechanism of dispersal. Seedbank perisistence: long=5+ years short= months to 1 year
Chapter 5 Perennial Broadleaf Herbs, Sedges and Succulents Weed Management Table<br />
Some suggested methods of management and control Similar natives often<br />
mistaken for weeds<br />
Biennial, rapidly replacing the native Malva on islands off the coast of Perth. Cut to ground and paint stump with glyphosate. Weed mat<br />
will prevent germination of seedlings.<br />
M. australiana 274, 167, 242, 197<br />
Try 0.5 % glyphosate + Pulse®. 167, 242, 222<br />
Control in seedling stage, older plants resistant to herbicide. Relatively tolerant of glyphosate. Hand remove small populations in areas not<br />
susceptible to erosion. Spot spray chlorsulfuron 0.4 g/10 L + spray oil.<br />
Control in seedling stage, older plants resistant to herbicide. Relatively tolerant of glyphosate. Hand remove small populations - remove<br />
entire root stystem. Spot spray chlorsulfuron 0.4 g/10 L + spray oil.<br />
Control in seedling stage, older plants resistant to herbicide. Relatively tolerant of glyphosate. Hand remove small populations - remove<br />
entire root stystem. Spot spray chlorsulfuron 0.4 g/10 L + spray oil.<br />
Control in seedling stage, older plants resistant to herbicide. Relatively tolerant of glyphosate. Hand remove small populations - remove<br />
entire root stystem. Spot spray chlorsulfuron 0.4 g/10 L + spray oil.<br />
Hand pull isolated plants. Regular spot spraying with 1 % glyphosate is reported to give effective control in Australia. Resistance to<br />
glyphosate reported from the Mediterranean.<br />
300, 38, 49, 228,<br />
167, 242, 222<br />
300, 38, 49, 228,<br />
167, 242, 222<br />
300, 38, 49, 228,<br />
167, 242, 222<br />
300, 38, 49, 228,<br />
167, 242, 222<br />
P. debilis 248, 18, 167, 242<br />
Hand pull isolated plants taking care to remove entire stem - will reshoot from below ground level. Spot spray metsulfuron methyl 5 g/ha +<br />
Pulse ® . Easy target after fire.<br />
300, 101, 167, 242<br />
Dig out isolated plants - cut root at least 5 cm below ground. Spray with 1 % glyphosate + Pulse ® . 300, 21, 101, 167,<br />
242, 222<br />
Spray in early stages of growth with 1 % glyphosate. P. debilis, P. drummondii,<br />
P. exilis<br />
300, 336, 167, 242,<br />
222<br />
Spray in early stages of growth. Suggest 1 % glyphosate. 30, 336, 151, 167,<br />
242<br />
Spot spray with 1 % glyphosate in early bud stage, cultivation of older plants will spread root fragments. R. dumosus,<br />
R. drummondii<br />
96, 248, 326, 167,<br />
242<br />
Spot spray with 1 % glyphosate in early bud stage, cultivation of older plants will spread root fragments. 96, 248, 326, 167,<br />
242<br />
Spot spray with 1% glyphosate in early bud stage, cultivation of older plants will spread root fragments. 96, 248, 326, 167,<br />
242<br />
Hand remove small infestations. Seed generally does not move far from parent plants. Boiling water reported to destroy 99 % of soil<br />
seed bank.<br />
130, 167, 242<br />
Hand remove small infestations. Lontrel ® at 10 mL/10 L (500 mL/ha) + wetting agent just before stem elongation in spring. 339, 228, 167, 242<br />
Wipe with 50 % glyphosate solution before flowering. Dense infestations in degraded areas spot spray 0.4 g chlorosulfuron plus 25 mL<br />
wetting agent in 10 L of water when plants actively growing.<br />
300, 153, 25, 228,<br />
167, 242, 222<br />
Spot spray with 1 % glyphosate before flowering. Lontrel ® 3 mL/10 L (150 mL/ha) up to 6 leaf stage. 77, 102, 167, 242<br />
Roundup Biactive ® (360 g/L) at13 mL/L. Apply in the period between male flowers opening, and 6 weeks after female flowers emerge.<br />
Avoid producing run-off or spray drift. Cutting shoots 15 cm below the water surface two to three times in a season when actively growing,<br />
but before seeds are formed, greatly reduces stands.<br />
Hand pull small infestations. Spray larger areas with 2 % glyphosate + 2 % Pulse® ; spray when plants have approximately 5 cm new<br />
growth in 8-12 weeks - repeat applications will be required.<br />
Reference<br />
T. domingensis 230a, 96, 167, 242<br />
21, 22, 228, 167,<br />
242, 222<br />
73
74<br />
Chapter 6 Trees, Shrubs<br />
and Climbers<br />
The Woody <strong>Weeds</strong><br />
The term “woody weed” refers to any woody perennial<br />
tree, shrub or climber that has established within<br />
bushland outside its natural range. Unlike the<br />
herbaceous plants covered in previous chapters,<br />
woody plants have secondary growth, which means<br />
their stems continue to lay down new tissue increasing<br />
in girth even after they stop increasing in height.<br />
Most woody weeds recorded around the world were<br />
deliberately introduced as ornamentals or forestry<br />
species (Binggeli et al. 1998). Many of the species found<br />
in south west Western Australia come from southern<br />
Africa, South America and the Mediterranean region.<br />
Planting of ‘Australian natives’ in parks and bushland,<br />
has also resulted in the naturalisation of numerous<br />
weedy Australian species. Of the 81 tree and shrub<br />
species recorded as environmental weeds of the Swan<br />
Coastal Plain and Jarrah Forest, 39 % are eastern<br />
Australian species (Keighery 1999a). Given the<br />
opportunity, even Western Australian species can<br />
become weedy outside their natural range (Box 6.1).<br />
The biology of woody plants varies considerably. Most<br />
reproduce by seed – but not all. Some are deciduous,<br />
some evergreen. Many resprout when felled, some<br />
sucker, others simply die. Woody species may retain<br />
their fruit in the canopy, releasing it when the tree is<br />
damaged, or shed it as soon as it is ripe. Mammals,<br />
birds, insects, wind, water or gravity may disperse fruit.<br />
Seed may remain viable for years, or only weeks, and<br />
plant lifespan can vary from several to hundreds of<br />
years. Some woody species produce toxins that inhibit<br />
growth of other plants. The toxins produced by the<br />
Tree-of-heaven (Ailanthus altissima) are so strong their<br />
Box 6.1 Western Australian natives can be weeds too.<br />
potential use as a natural herbicide has been<br />
researched (Lin et al. 1995).<br />
Common characteristics that make woody weeds highly<br />
competitive (Binggeli et al. 1998, Buist et al. 2000) include:<br />
• Fast growth.<br />
• Early maturity and prolific seeding.<br />
• High seed germinability.<br />
• Readily germinate and grow within shady conditions.<br />
• Ability to grow at high densities.<br />
• Resprouting or suckering response.<br />
• Lack of seed and plant predation in the naturalised<br />
habitat.<br />
• Resilience to a range of environmental conditions.<br />
• A rapid response to changes in space, light,<br />
nutrient or water availability.<br />
As a group the woody weeds pose several problems to<br />
bushland managers. They are often large, both difficult<br />
to dig out and to spray without causing damage to the<br />
surrounding vegetation. Their removal can result in the<br />
loss of desirable shade and cause a considerable<br />
increase in the space, light and nutrients available to<br />
other weeds that might be present. The act of removal<br />
itself can damage surrounding vegetation and spread<br />
propagules. This chapter discusses these problems and<br />
looks at some of the different treatment options<br />
available. In particular it highlights the relationship<br />
between treatment approach and the plant’s ability to<br />
resprout and sucker.<br />
“In Western Australia thirty five species of Western Australian plants have become naturalised, largely outside their<br />
ranges, from plantings” (Keighery 2002b). It is important to emphasise the use of locally collected material<br />
(seed or cuttings) when planting in or near bushland areas. Likewise, correct identification of plants from<br />
which material is collected is also essential.<br />
Table 1. Some Western Australian natives known to have naturalised outside their native range (adapted from Keighery, G.,<br />
unpublished report).<br />
Acacia acuminata (Jam)<br />
Acacia blakelyi<br />
Acacia lasiocalyx<br />
Acacia microbotrya (Manna Wattle)<br />
Acacia myrtifolia<br />
Allocasuarina huegeliana (Rock Sheoak)<br />
Banksia caleyi (Caley's Banksia)<br />
Callitris glaucophylla<br />
Callitris preissii (Rottnest Island Pine)<br />
Calothamnus chrysantherus (Clawflower)<br />
Calothamnus graniticus<br />
Calothamnus quadrifidus (One-sided Bottlebrush)<br />
Calothamnus validus (Barrens Clawflower)<br />
Ceratopteris thalictroides<br />
Diplolaena dampieri (Southern Diplolaena)<br />
Eucalyptus camaldulensis (River Red Gum)<br />
Eucalyptus conferruminata (Bald Island Marlock)<br />
Illustration provided by: IFAS, Centre for Aquatic Plants University<br />
of Florida, Gainesville, 1996<br />
Eucalyptus erythrocorys (Illyarrie Gum)<br />
Eucalyptus todtiana (Coastal Blackbutt)<br />
Grevillea leucopteris (White Plume Grevillea)<br />
Hakea costata (Ribbed Hakea)<br />
Hakea francisiana (Emu Tree)<br />
Hakea pycnoneura<br />
Hibbertia cuneiformis (Cut-leaf Hibbertia)<br />
Kunzea baxteri<br />
Melaleuca nesophila<br />
Melaleuca pentagona<br />
Melia azedarach (Cape Lilac)<br />
Verticordia monadelpha (Woolly Featherflower)<br />
Actual or potential serious weeds<br />
Agonis flexuosa (Peppermint)<br />
Chamelaucium uncinatum (Geraldton Wax)<br />
Melaleuca lanceolata (Rottnest Tea Tree)
Impacts<br />
Invasive woody species can have profound effects on<br />
the structure and diversity of the invaded bushland.<br />
Weedy trees and shrubs often form dense stands,<br />
shading out and preventing the germination and<br />
establishment of native species (Gleadow and Ashton<br />
1981, Gleadow 1982, Weiss and Noble 1984, Rose and<br />
Fairweather 1997, Goodland et al. 1998, Mullett 2002).<br />
Over a 25 year period at Croydon North in Melbourne,<br />
scattered plants of Sweet Pittosporum (Pittosporum<br />
undulatum) coalesced into a dense stand, obliterating<br />
nearly all the original understorey (Gleadow and<br />
Ashton 1981). Closer to home, on the Darling Scarp<br />
east of Perth, stands of eastern Australian Acacias,<br />
including Cootamundra Wattle (Acacia baileyana),<br />
Silver Wattle (Acacia dealbata) and Flinders Range<br />
Wattle (Acacia iteaphylla), form dense stands in the<br />
understorey of the Jarrah Forest. The establishment of<br />
dense weed infestations also impact on the fauna.<br />
Habitat and food sources are lost, which may lead to<br />
decreases in native animal diversity.<br />
It may only require one or two plants to establish and<br />
reach maturity for the source of an infestation to form.<br />
The seed rain that follows, coupled with the ability to<br />
germinate in shady conditions and/or take rapid<br />
advantage of disturbance events, is enough to allow<br />
dense establishment of the plant. In Kings Park and<br />
Botanic Garden, Perth, a small number of Acacia<br />
lasiocalyx were planted on the edge of bushland<br />
around 1967. A wildfire in 1989 resulted in mass<br />
germination of the species and it was realised this<br />
Western Australian Wheatbelt species had become a<br />
serious weed. By 1993, when the non-sprouting trees<br />
were cut out by a group of dedicated volunteers,<br />
A. lasiocalyx had covered 0.6 hectares of the park’s<br />
bushland area (Dixon 2001, Dixon pers. comm. 2002).<br />
A dense infestation of Acacia lasiocalyx in Kings Park <strong>Bushland</strong>.<br />
(Photograph by Bob Dixon).<br />
Chapter 6 Trees, Shrubs and Climbers<br />
Mechanisms of spread<br />
Woody plants may reproduce by seed, or create clones<br />
from vegetative fragments or propagules. Dispersal of<br />
propagules, over short or long distances, followed by<br />
successful establishment results in the spread of the<br />
plant.<br />
• Birds, insects and mammals spread the seeds of<br />
many invasive woody species. Seeds of Brazilian<br />
Pepper (Schinus terebinthifolius), Edible Fig (Ficus<br />
carica) and Blackberry (Rubus spp) are all ingested<br />
by birds and germinate in their droppings. Finding<br />
weed species growing at the base of perching trees<br />
is a good indication that these particular weeds<br />
are spread by birds (Gleadow 1982, Blood 2001).<br />
Propagules also attach to feathers and fur or can<br />
be carried by ants (many Acacia species).<br />
• Wind is an effective disperser of seed especially if<br />
an individual plant emerges above the canopy (eg.<br />
Tamarisk, Sheoaks and Eucalypts). Dispersal<br />
distance is considerably less than with birddisseminated<br />
species.<br />
• Water can carry propagules down stream and,<br />
during floods, to distant sites. The seeds of many<br />
Acacia species, stems of Willows (Salix spp), and<br />
aerial tubers of Madeira Vine (Anredera cordifolia)<br />
are all carried by water.<br />
• Garden rubbish dumped in bushland introduces<br />
various weed propagules. Cuttings of Australian<br />
natives, especially eastern Australian Bottlebrush<br />
(Callistemon) and Wattle (Acacia) species, are<br />
commonly dumped in bushland under the<br />
misguided belief that they came from there!<br />
• Planting of non-local tree species within bushland<br />
can also be the source of woody weed invasions<br />
(eastern Australian species and Western Australian<br />
species planted outside their natural range).<br />
• Individual plants may spread locally by vegetative<br />
reproduction - stem layering or root suckering.<br />
Resprouting, suckering and apical control<br />
Resprouting and suckering are mechanisms by which<br />
many woody plants resist or recover from fire, storm<br />
or grazing damage.<br />
Suckering is the formation of sprouts from<br />
adventitious buds in the lateral roots. Suckers arise<br />
most often at root branch intersections, areas of root<br />
irregularity or points of injury. Individual plants form<br />
as the sucker develops its own root system and old<br />
root connections are broken. Some species sucker in<br />
response to crown removal or root damage.<br />
75
76<br />
Chapter 6 Trees, Shrubs and Climbers<br />
Resprouting, or coppicing, refers to the growth of<br />
shoots from dormant buds (epicormic buds) in the<br />
stem or root crown after the canopy has been removed<br />
or damaged. The ability to sprout can be agedependent.<br />
Epicormic buds may not be laid down until<br />
a plant reaches a certain maturity. In some species the<br />
woody rootstock contains epicormic buds and is<br />
termed a lignotuber (common in Eucalypts).<br />
suckering from root node<br />
In woody plants, the term apical dominance describes<br />
the control the shoot tip has over the current year’s<br />
growth (Cline 1997). When apical dominance is<br />
removed, as in tip pruning, the side buds are able to<br />
develop and the plant becomes bushier. On a whole<br />
tree scale, apical control describes the inhibition of<br />
lateral branch growth by the top portion of the tree<br />
crown, the canopy (Cline 1997, Wilson 2000). When the<br />
crown is cut off, apical control is removed and<br />
epicormic buds in the lower trunk and root crown are<br />
free to sprout. The sprouting response is due, in part,<br />
to removal of plant growth hormones, in particular<br />
auxins (Cline 2000). However, release of carbohydrates,<br />
nutrients and water previously used by the canopy,<br />
combined with increased light and space also play a<br />
role (Cline 2000). Suckering from lateral roots may also<br />
occur with the release of apical control. This has been<br />
shown for a number of species including Quaking<br />
Poplar (Populus tremulus), Black Locust (Robinia<br />
pseudoacacia), Tree-of-heaven and Lantana (Lantana<br />
camara) (Anon. 1999, Binggeli et al. 1998, Converse<br />
1984b, Converse 1987).<br />
The implication of apical control for management is<br />
simple – removal of the crown above epicormic buds<br />
enhances resprouting and, in many species, suckering.<br />
Herbicide treatment is required to kill these species.<br />
Species known to sucker should be treated using basal<br />
bark or stem injection methods (see following). These<br />
methods allow systemic herbicides to be translocated<br />
around the plant without the release of apical control<br />
which would initiate the suckering response.<br />
Management and control<br />
resprouting or<br />
coppicing from trunk<br />
When managing woody weeds the approach taken and<br />
the techniques used will depend on: The size and<br />
distribution of the infestation, the species in question,<br />
the plant age and size, the presence of other invasive<br />
weeds, the impact on other plants and animals, the<br />
sensitivity of the area and the size and skills of the<br />
labour force.<br />
The general approach<br />
• As with other weed groups, baseline maps<br />
illustrating the distribution of target species allow<br />
for strategic planning of control and follow-up work.<br />
• Isolated trees/shrubs/climbers and small<br />
infestations in good bushland should be removed<br />
first, preferably before the year’s seed crop has<br />
ripened. Modeling has shown that eradicating<br />
small founding populations slows the overall<br />
invasion process (Moody and Mack 1988).<br />
• Managing heavily invaded areas poses a greater<br />
problem (Goodland et al. 1998). It is important to<br />
understand the structure and ecology of the<br />
vegetation community invaded. Large infestations<br />
may need to be removed slowly over time to allow<br />
the native plant community to regenerate and<br />
resume its role in the ecosystem.<br />
Where a dense native overstorey has been<br />
gradually replaced by woody weeds, the<br />
subsequent removal of the weed infestation can<br />
create large gaps in the canopy that may be<br />
detrimental to surviving native plants. Opening up<br />
the canopy favours the establishment of exotic<br />
grasses and other weeds and allows intense light<br />
to reach the shade-adapted native understorey. In<br />
contrast, removing weed trees from open<br />
woodlands, shrublands, herblands or grasslands,<br />
returns the status quo in terms of vegetation<br />
structure and sunlight intensity.<br />
Established woody weeds may be stabilising<br />
susceptible areas, especially along watercourses<br />
and on steep embankments. Removal of more than<br />
a few individuals at a time may result in severe<br />
erosion.<br />
• Until the infestation is removed, there will be<br />
continued spread of propagules within the area<br />
and seedlings need to be removed as they appear.<br />
Always plan to follow up treatments for several years<br />
to provide the greatest chance of eradicating the weed<br />
from an area. The few survivors or missed plants will<br />
quickly re-establish the infestation if left for a number<br />
of years.<br />
Physical control – without herbicide<br />
<strong>Manual</strong> and mechanical techniques such as pulling,<br />
cutting, stripping and ring-barking, may be useful to<br />
control some woody weeds, particularly if the<br />
population is relatively small.<br />
Note: Chainsaws should not be used unless operators are certified<br />
and supervised.<br />
Hand-weeding<br />
Labour intensive but effective, hand-weeding is<br />
suitable for removing some light infestations of some<br />
weed seedlings and small saplings. However, the use<br />
of machinery or a large, inexperienced labour force can<br />
cause extensive soil disturbance and vegetation<br />
trampling.
• Seedlings and small shrubs can be carefully pulled<br />
by hand, ensuring removal of the taproot. Seedlings<br />
can be distinguished by the presence of a long<br />
taproot while suckers have a hockey stick shaped<br />
end, where they have broken off the parent root.<br />
• Saplings and mature trees should not be removed<br />
using this method. The disturbance of soil<br />
structure and damage to native vegetation is<br />
counter-productive and may lead to invasion by<br />
other weeds. In addition, such disturbance of<br />
suckering species may stimulate growth from root<br />
fragments left in the soil.<br />
• Integration of hand-weeding with other<br />
techniques is often appropriate. Removal of large<br />
trees by felling or herbicide treatment may be<br />
followed up by hand-removal of the flush of<br />
seedlings that are likely to appear.<br />
Felling and ring-barking<br />
These two techniques are suitable for trees and shrubs<br />
that do not resprout. The methods are labour intensive<br />
and may not be suitable for large infestations. Ringbarking<br />
is fiddley and the felling approach requires<br />
removal of branches from the site. However, on small<br />
infestations both techniques provide a simple, targetspecific,<br />
control option.<br />
Ring-barking involves cutting away a strip of bark,<br />
usually at least 10 cm wide, all the way around the<br />
trunk. The strip must be cut deep enough to stop the<br />
flow of photosynthates (plant food) between the<br />
growing points of the tree. To be successful, the phloem<br />
and vascular cambium (Box 6.2) must be completely<br />
severed around the circumference of the tree. Felling<br />
the tree at the base has effectively the same result,<br />
cutting the flow of food between roots and crown.<br />
• Seedlings can be quickly slashed at ground level if<br />
not growing closely among native vegetation.<br />
• Non-sprouting shrubs, saplings and mature trees<br />
can be cut off at, or very near, ground level below<br />
any branches or dormant buds. Many basically<br />
non-sprouting plants have epicormic buds higher<br />
up the trunk so it is important to cut off the trunk<br />
as close to the ground as possible.<br />
• Keep in mind that surrounding vegetation can be<br />
damaged when trees and large shrubs are felled,<br />
and as branches are carried out.<br />
Chemical control<br />
Although the introduction of chemicals into bushland<br />
should be minimised, herbicide treatment remains the<br />
most successful means of control for many woody<br />
species. There are some general rules of thumb when<br />
using chemicals to control woody weeds, but treatment<br />
effectiveness will vary across species and sites.<br />
• Apply herbicides as selectively as possible to<br />
target weeds, minimising damage to the<br />
surrounding native vegetation.<br />
• Regardless of the application method chosen, all<br />
herbicides should be applied when the target<br />
species is actively growing.<br />
Chapter 6 Trees, Shrubs and Climbers<br />
• Herbicides should not be applied when plants are<br />
stressed; either through drought, flooding, disease,<br />
insect damage or previous herbicide application.<br />
• Effective control of many woody plants requires a<br />
systemic herbicide to be used (Box 6.2, Chapter 8).<br />
• Herbicides are rarely 100 % effective and an<br />
integrated control program will nearly always give<br />
the best result. Use a combination of different<br />
herbicide application techniques, physical methods<br />
and regeneration/direct seeding programs.<br />
Note: Anyone applying herbicides should have appropriate training<br />
in the safe use and handling of relevant chemicals (Chapter 8).<br />
Foliar treatment<br />
Treating the leaves or foliage of large trees with<br />
herbicide (foliar treatment) can be cumbersome and<br />
expensive. In addition, many tree species have thick,<br />
waxy leaf cuticles that make them highly resistant to<br />
spray. However, this approach can be useful for treating<br />
large, dense infestations of resprouting seedlings and<br />
small shrubs in degraded areas. Foliar treatment is not<br />
recommended for saplings and mature trees. It is<br />
impossible to spray the canopy of even a small tree<br />
within bushland without off-target damage.<br />
Cut and paint<br />
Cut and paint is a target-specific method, suitable for<br />
many small trees and shrubs that resprout. Successful<br />
control requires careful application – it is essential to<br />
apply the herbicide immediately to cut stumps. If<br />
delayed, the tree seals the wounded stump, preventing<br />
absorption of the herbicide. Large trees and shrubs<br />
may need to be cut down sequentially to avoid injury<br />
to workers and damage to the surrounding bush. Cut<br />
down the plant until one metre of trunk remains above<br />
the ground. With herbicide ready, cut the remaining<br />
trunk off close to ground level, apply herbicide<br />
immediately to the stump. The cut and paint method is<br />
labour intensive and can leave large gaps in the<br />
canopy. It is not viable for large infestations unless an<br />
experienced work crew is available and a consistent,<br />
systematic effort can be made over time.<br />
• Shrubs and small trees can be treated by felling<br />
the plant close to ground level (5-15 cm) and<br />
immediately painting the exposed stump with a<br />
systemic herbicide. The entire surface of small<br />
stems can be painted using a paintbrush or<br />
sponge applicator. On larger stems, focus on the<br />
outer ring of wood containing the phloem, xylem<br />
and vascular cambium.<br />
77
78<br />
Chapter 6 Trees, Shrubs and Climbers<br />
Box 6.2 Herbicide translocation in woody plants<br />
Whether applied to the leaves, roots or stem of a tree, herbicide is transported around the plant within the<br />
xylem and phloem tissue. Understanding the function of these tissues and that of the vascular cambium is<br />
important in woody weed management.<br />
Phloem is the tissue that is exposed when the<br />
outer bark is peeled away. These living cells are<br />
linked by protoplasm, forming an avenue for bi-<br />
inner bark and phloem<br />
directional movement of hormones and<br />
outer bark<br />
photosynthates between shoots and roots.<br />
Vascular cambium describes the thin layer of<br />
cells with the ability to divide that lie beneath<br />
the phloem. Each year these cells produce a new<br />
layer of phloem toward the outside of the tree<br />
and a new layer of xylem, or wood, toward the<br />
inside.<br />
Xylem consists of four kinds of cells. Tracheids<br />
and vessels, which at maturity are dead, are<br />
hollow cells responsible for the upward transport<br />
of water and dissolved solutes. Fibres provide<br />
structural strength and parenchyma cells, when<br />
living, provide a pathway for lateral movement<br />
across the xylem. While the parenchyma cells are<br />
alive, the xylem is physiologically active and<br />
considered part of the sapwood. When the<br />
parenchyma cells die, the xylem becomes<br />
heartwood; it provides structural support but no<br />
longer transports water and solutes. The<br />
sapwood can often, but not always, be<br />
distinguished by its lighter colour.<br />
Uptake of herbicides in phloem<br />
Herbicides with a molecular structure that allows them to cross living plant cell membranes may be carried in<br />
the phloem. They are called systemic herbicides and are readily taken into the phloem through leaves and<br />
roots. Phloem-mobile, systemic herbicides are not restricted to movement in the phloem however (Chaney<br />
1985, Sindel 2000). Uptake directly into the phloem cells via trunk injection is unlikely; the cell contents are<br />
under positive pressure and when damaged, are forced out. Damaged cells are also quickly sealed with plugs of<br />
gelatinous material (Chaney 1985, Chaney no date).<br />
Movement in the sapwood<br />
heartwood<br />
vascular cambium<br />
sapwood<br />
Cross-section of a tree trunk illustrating the location of outer bark, inner<br />
bark and phloem, vascular cambium and xylem (both sapwood and<br />
heartwood).<br />
All herbicides with some water solubility can be transported in the xylem (Sindel 2000). Within the xylem,<br />
continuous columns of water extend from the roots to the leaf cells. Unlike phloem cell content which is under<br />
positive pressure, liquid in the xylem is under negative pressure; as water evaporates from stomatal pores in<br />
the leaves, more is drawn upwards (Chaney 1985, Kozlowski and Pallardy 1997). Injected herbicide is initially<br />
pulled up into the tree due to this strong negative pressure. Once in the xylem, phloem-mobile herbicides can<br />
move across cell membranes making their way into the phloem to be transported around the plant (Chaney<br />
1985, Sindel 2000). However, rapid application is vital. Trunk injection severs xylem cells, breaking the<br />
continuity of the water, introducing air and initiating wound healing - all processes that impede the uptake of<br />
injected substances (Chaney 1985).<br />
Soil moisture, air temperature, and relative humidity affect the rate of water movement. For most temperate<br />
species, warm days with low relative humidity are associated with high transpiration. Injected substances are<br />
rapidly taken up. In contrast, when the temperature is cool or the relative humidity high, conditions that slow<br />
down transpiration, the rate of water uptake from the soil will be slow and trunk injection less effective. There<br />
are of course exceptions. Many Australian species, adapted to the hot dry climate, conserve water by not<br />
transpiring in the heat of the day during the summer months, and thus should not be injected at this time.
Felling large trees can result in damage to the native<br />
vegetation. Furthermore, the cut and paint approach<br />
may not deliver the quantity of herbicide required to<br />
kill the rootstock.<br />
Removing branches from the site: Minimise damage<br />
to surrounding vegetation by planning your removal<br />
route in advance and cutting back large or bushy<br />
plants sequentially. Where possible avoid cutting down<br />
plants when they are covered in ripe fruit or seed, as<br />
carrying out the branches will help spread the weed!<br />
Never leave cut branches bearing seed or fruit in<br />
bushland – even unripe seed can ripen on cut<br />
branches. If possible put seed-bearing material into<br />
bags before carrying out of the bushland. Some plants,<br />
like Willow, Edible Fig and Poplar (Populus species) will<br />
also grow from branch cuttings. To avoid spreading<br />
such plants unwittingly, these species can be left<br />
Chapter 6 Trees, Shrubs and Climbers<br />
Box 6.3 Brazilian Pepper – a successful sucker<br />
Brazilian, or Japanese Pepper (Schinus<br />
terebinthifolius), is a large shrub to small evergreen<br />
tree. Separate male and female plants produce small,<br />
cream flowers, but only the female tree produces the<br />
distinctive clusters of small red berries. The dark<br />
green leathery leaves emit a strong turpentine or<br />
peppery smell when crushed. Widely planted as an<br />
ornamental, Brazilian Pepper has successfully<br />
naturalised in more than 20 countries in two circumglobal<br />
belts of roughly 15-30° North and South. The<br />
weed can form dense thickets, which shade out and<br />
smother native plants. Most invasive in moist<br />
situations, it also tolerates dry conditions and has<br />
been found growing and spreading on cliffs,<br />
roadsides and in bushland. Birds are the primary<br />
seed dispersal agents, although many mammals,<br />
gravity and water also play a part. Root suckers<br />
contribute greatly to local spread, especially after<br />
crown or root damage. In moist conditions branch<br />
cuttings will also take root (Anon. 1998, Elfers 1988a,<br />
Ferriter 1997, Parsons and Cuthbertson 2001, Randall<br />
and Marinelli 1996, Panetta and McKee 1997).<br />
Successful strategies – some Brazilian<br />
Pepper biology<br />
• Brazilian Pepper can reach reproductive age<br />
within three years of germination.<br />
• Bears seed from April until October – an<br />
extensive period for seed dispersal.<br />
• Seeds are dispersed by birds.<br />
• Seedlings can grow in dense shade.<br />
• Established trees are not usually killed by fire.<br />
• Stems sprout prolifically after canopy damage.<br />
• Suckering is enhanced by root or canopy<br />
damage.<br />
standing and treated by stem injection or basal bark<br />
treatment.<br />
Stem injection<br />
As outlined in the section on apical control, plants may<br />
sucker primarily in response to canopy or root<br />
damage. Species which root sucker (including Silver<br />
Wattle, Lantana, Poplar and Brazilian Pepper) may be<br />
best treated by stem injection or basal bark methods<br />
(Box 6.3).<br />
Stem injection techniques reduce herbicide damage to<br />
the surrounding environment. By placing the herbicide<br />
directly into the tree, contamination of soil and water,<br />
and damage to off-target plants is minimised. Response<br />
to stem injection will vary, depending on species,<br />
xylem anatomy, sap components, and environmental<br />
conditions (Box 6.2 & 6.4).<br />
Controlling Brazilian Pepper<br />
Physical control<br />
Seedlings: Carefully hand-weed being sure to<br />
remove all the root. Seedlings have a distinct tap<br />
root, suckers snap off leaving a hockey stick<br />
shaped end.<br />
Saplings and mature trees: Do not fell as trees will<br />
coppice. Damage to the root system or canopy<br />
stimulates root suckering.<br />
Chemical control<br />
Saplings and mature trees:<br />
Cut and paint: Does not allow sufficient herbicide to<br />
enter the system and cutting stimulates suckering.<br />
Only offers temporary control and the resultant<br />
resprouting, as much as 26 months later (Panetta<br />
and Anderson 2001), and root suckering forms<br />
denser thickets.<br />
Stem injection/ basal bark: Correctly applied these<br />
techniques are preferable to the cut and paint<br />
method, resulting in a relatively high proportion of<br />
tree death and minimal suckering in the survivors.<br />
Resprouts: Foliar spray only if original trunk was<br />
small; if very large root stock, foliar spray over the<br />
proportionately small area of regrowth will not<br />
deliver enough herbicide to kill the plant. Instead,<br />
inject herbicide into the root crown.<br />
Timing<br />
For maximum effect herbicide should be applied<br />
during summer when plants are actively growing<br />
and, in wet areas, where roots are not waterlogged.<br />
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Chapter 6 Trees, Shrubs and Climbers<br />
Drill and fill: Holes 8-10 mm in diameter are drilled<br />
down at an angle into the sapwood around the base of<br />
the tree at 50-100 mm intervals, ensuring there is an<br />
injection point below each major branch. Inject<br />
approximately 5 mL of herbicide solution into the<br />
holes immediately after drilling each one. The hole<br />
depth will depend on the wood anatomy of the tree<br />
and thickness of the bark, but 30-50 mm is usually<br />
appropriate. A cordless drill or brace and bit can be<br />
used for drilling and the herbicide injected from a<br />
squirt bottle, large syringe or a drench gun.<br />
Alternatively, Sidewinder Tree Injectors ® have been<br />
specifically designed for this task.<br />
Note: Common practice is to inject undiluted herbicide. While this is<br />
sometimes necessary, in other situations a 50 % or even 20 % solution<br />
is adequate.<br />
Frilling: Herbicide can also be injected into the<br />
sapwood by means of frilling. An axe is used to make<br />
cuts into the sapwood around the base of the tree. The<br />
cuts should be 30-50 mm wide by 20-30 mm deep<br />
(ensure cuts penetrate into the sapwood). Herbicide<br />
should be injected immediately into the cuts.<br />
Basal bark<br />
Basal bark treatment is useful on small stems – less<br />
than 20 cm in diameter and some larger trees with thin<br />
bark. The lower 60 cm of bark is<br />
painted or sprayed until<br />
dripping, with a<br />
herbicide and bark<br />
penetrant solution. The<br />
bark penetrant (usually<br />
diesel) carries the<br />
herbicide through thin bark<br />
and into the sapwood. Bark<br />
thickness and characteristics<br />
can influence effectiveness of this<br />
technique. Bark should also be<br />
dry and relatively dirt free. This<br />
method is quicker than<br />
injection or cut and paint, distributes the herbicide<br />
evenly around the tree base and thus evenly into the<br />
sapwood and is useful in tangled thickets.<br />
Treating climbers and brambles<br />
Climbers present their own set of problems when it<br />
comes to control. They scramble over and through<br />
native vegetation making targeted spraying of foliage<br />
difficult. Climbers often have thin stems that cannot be<br />
injected, and when cut off at the base provide an<br />
inadequate surface area for herbicide uptake. They<br />
may also have the ability to sucker and/or stem layer,<br />
putting down roots from the stem into the ground and<br />
trunks or branches of other plants (Morning Glory<br />
(introduced Ipomoea spp), Japanese Honeysuckle<br />
(Lonicera japonica)). For these species, cutting off<br />
stems at the base only cuts one part of the nutrient<br />
supply and is ineffective. Many climbing species<br />
including Dolichos Pea (Dipogon lignosus), Morning<br />
Glory and Madeira Vine, have a large woody or<br />
tuberous root stock and techniques are required that<br />
introduce enough herbicide into the plant to kill it.<br />
Scrape and paint<br />
An effective way of killing<br />
climbers that sucker or stem<br />
layer, is to scrape the stems<br />
with a knife and<br />
immediately paint the<br />
exposed wood with a<br />
systemic herbicide.<br />
This method<br />
increases the surface<br />
area available for<br />
herbicide uptake and<br />
allows the herbicide to<br />
be translocated throughout the<br />
plant – including into secondary<br />
root systems. One or two long<br />
scrapes (300 mm) should be made<br />
along the same side close to the<br />
base of each stem. The scrapes<br />
should be deep enough to expose<br />
the sapwood, but not sever the<br />
stem. Treatments should be<br />
carefully monitored and any<br />
resprouts foliar sprayed or<br />
re-scraped and painted<br />
before they become<br />
entangled with native<br />
vegetation. The scrape and paint approach is suitable<br />
for Madeira Vine, which is particularly difficult to<br />
manage. It produces a multitude of both aerial and<br />
underground tubers which break off easily when the<br />
plant is disturbed and readily form new plants. With<br />
the scrape and paint method there is minimal<br />
disturbance to the canopy and aerial tubers will<br />
gradually wither and die on the plant (Muyt 2001).<br />
Remove and bag aerial tubers from the treatment area<br />
prior to scraping.
Foliar spray<br />
Foliage provides a large surface area for uptake of<br />
herbicides. If the climber is growing over low shrubs,<br />
the bulk of the material can be pulled back off and<br />
away from native plants and sprayed. A good penetrant<br />
should always be used. This method is suitable for:<br />
• Dense infestations where no native species are<br />
present and off-target damage will not occur.<br />
• Small infestations in relatively good bushland<br />
where labour is available to carefully pull vines<br />
away from native plants.<br />
Slash and spray<br />
Infestations of plants such as Blackberry, which form<br />
thickets of stems up to two metres high can be difficult<br />
to treat. Larger, dense infestations in highly disturbed<br />
areas are better treated by leaving the plants intact<br />
and spraying with a systemic herbicide. Intact plants<br />
provide more leaf area, increasing the amount of<br />
herbicide that can be taken into the plant (Bruzzese<br />
and Lane 1996).<br />
Chapter 6 Trees, Shrubs and Climbers<br />
Box 6.4 Xylem anatomy and sapwood porosity<br />
In plants, water and its dissolved solutes (including herbicide) are transported along the pathway of least<br />
resistance and this varies depending on the xylem anatomy. In cross section there are three main (and an array<br />
of intermediate) arrangements of vessels and tracheids within woody species: Non-porous, diffuse porous and<br />
ring porous (Chaney 1985, Kozlowski and Pallardy 1997).<br />
Non-porous anatomy is found in gymnosperms, the conifers, which only have small, narrow tracheids for water<br />
uptake. Tracheids produced early in the growing season, the earlywood, have the largest diameters and are the<br />
main pathway for water transport. Three or four annual growth rings of xylem may be active (Kozlowski and<br />
Pallardy 1997).<br />
Diffuse porous anatomy occurs in angiosperm trees, or hardwood species. Vessels, rather than tracheids are<br />
the primary water conductors. In diffuse porous woods, vessels of similar diameter are uniformly scattered in<br />
the early and latewood. The proportion of the sapwood conducting water varies between species, but<br />
commonly vessels found in the outer three or four growth rings are responsible.<br />
Ring porous anatomy also occurs in angiosperms. However, here the vessels of the earlywood are larger in<br />
diameter than those of the latewood. It is these larger vessels of the current growth increment that conduct<br />
99 % of the water and solutes (Zimmerman and Brown 1971, Chaney 1985, Kozlowski and Pallardy 1997).<br />
The movement of sap upwards through the tree also varies between species. Sap may move in a continuous<br />
vertical path, from root to tip, although this is an exception not the rule (Zimmerman and Brown 1971).<br />
Depending on the arrangement of tracheids and vessels, sap may travel in spiral ascent turning right or left,<br />
interlocked ascent and sectorial straight ascent (Chaney 1985, Kozlowski and Pallardy 1997). Spiral ascent<br />
allows the most complete distribution of water from an individual root to many branches (Kubler 1991) and<br />
thus would distribute injected herbicide most widely.<br />
Workers often report variable success rates using herbicide injection tecniques. Knowledge of anatomy and<br />
conduction pattern in the xylem helps tailor our injection technique, maximise its effectiveness and achieve<br />
consistent results. In non-porous and diffuse porous species, herbicide can be injected into the three or four<br />
annual growth rings below the bark. For ring porous species the injected material should be placed just<br />
beneath the bark in the current growth ring. The spacing of injection points can also influence treatment<br />
effectiveness. While there is usually some tangential spread of injected herbicides in the crown (Northcott<br />
1957), trees with straight ascent pathways will often require more injection points than those with a spiral<br />
ascent pathway. If not, the result may be death of the tree in strips, resulting in some dead branches while<br />
others still live. This has been observed in the Flame Tree, Erythrina x skysii (Rod Randall pers. comm. 2001).<br />
Foliar spraying small infestations of Blackberry among<br />
good bushland can result in off-target damage and<br />
accessing the root crown for injection is awkward. A<br />
number of community groups in the Perth region have<br />
found that slashing the plants, carting the bulk away<br />
and spraying regrowth once it is 50-100 cm high is<br />
effective. Blackberries will root readily from cuttings,<br />
so cut material must be removed from the site and<br />
disposed of carefully. Make sure plants are not cut<br />
down while in fruit as their removal from the bushland<br />
will spread the weed. Several follow-up treatments may<br />
be necessary.<br />
Treating resprouts<br />
No matter how good your technique, resprouting of<br />
trees, shrubs and climbers will occur in some species<br />
and/or under some conditions. Follow-up application of<br />
a systemic herbicide to foliage of resprouting plants and<br />
suckers is common practice. However, if the plant was<br />
very large and healthy prior to removal, the amount of<br />
chemical that can be applied to the foliage is likely to be<br />
insufficient to permanently damage the rootstock.<br />
Instead, try clearing away some soil and drilling holes<br />
around the base into the root crown. Fill the holes with<br />
herbicide as for the drill and fill technique.<br />
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Chapter 6 Trees, Shrubs and Climbers<br />
If herbicide use is not desirable and the offending weed<br />
resprouts, try cutting the stump and then repeatedly<br />
cutting any regrowth. This should eventually exhaust<br />
the plant’s reserves; but be prepared, it may take<br />
years! Alternatively, try stripping away all the bark<br />
from the stump to remove epicormic buds. This will<br />
not work for suckering species like Blackwood (Acacia<br />
melanoxylon), Flame Tree (Erythrina X sykesii), Tree-ofheaven<br />
or Eucalypts with lignotubers.<br />
Seedling recruitment<br />
The control of mature woody weeds usually frees light,<br />
space and nutrients, ideal conditions for seedling<br />
recruitment. Resources need to be made available to<br />
control any seedling flush. In some species seed is<br />
short-lived in the soil (Brazilian Pepper seed survives<br />
only six months) and follow-up control of seedlings is<br />
only required for a short period. For species with<br />
longer-lived seed, including many Acacia species,<br />
Broom (Genista spp) and Tagasaste (Chamaecytisus<br />
palmensis), follow-up may take a number of years. After<br />
the initial seedling flush is controlled, reduce further<br />
germination by encouraging the regeneration of native<br />
species. Keep out fire and other forms of disturbance<br />
until the soil weed seedbank disappears. In other<br />
situations it may be desirable to encourage weed seeds<br />
to germinate so they can be controlled and the soil<br />
seedbank exhausted.<br />
Injection and basal bark herbicide treatments can<br />
induce seed drop in bradysporous species such as<br />
Cajeput (Melaleuca quinquenervia) (Coladonato 1992b).<br />
These are plants that retain most of their seed in the<br />
canopy. The herbicide places the tree under stress<br />
causing the canopy-stored seed to be released which<br />
may result in prolific seedling recruitment. Such<br />
species can be treated using the cut and paint method.<br />
Ensure no seed-bearing material is left in the bushland.<br />
That said, canopy-stored seed is often only short-lived<br />
in the soil. Timing injection or basal bark treatments<br />
carefully can greatly reduce the amount of seed<br />
available for germination. For example, Sugar Gum<br />
(Eucalyptus cladocalyx) seed only remains viable in the<br />
soil for six months and the bulk of seed germinates in<br />
winter (Ruthrof 2001). By treating the plant in<br />
November, thereby inducing an early seed drop, most<br />
of the seed will lose viability over summer before<br />
seedling recruitment starts with the winter rainfall.<br />
Even when follow-up control of seedlings is<br />
meticulously undertaken, seed can still be brought in<br />
from an external source and susceptible bushland<br />
should be monitored at least annually.<br />
Making the most of unplanned fires<br />
Fire is a source of disturbance and a major mechanism<br />
for spread and establishment of many woody weeds.<br />
Invasive Australian species (Acacias, Melaleucas, and<br />
Eucalypts), are often favoured by post-fire conditions.<br />
Many have large numbers of seeds whose germination<br />
is enhanced by fire. Others resprout or sucker,<br />
increasing the density of stands.<br />
Nevertheless, for non-resprouting, non-suckering trees,<br />
particularly those with short to medium-lived seed,<br />
unplanned fire provides an opportunity for effective<br />
control. When mature plants have been killed or<br />
damaged by fire, follow-up treatment of seedlings by<br />
hand-weeding or spraying can greatly reduce the<br />
infestation.<br />
• Fire can enhance germination of some seedbanks –<br />
resulting in mass germination and reducing the<br />
requirement for staggered spray programs. At<br />
Kings Park, Perth, mature plants of the resprouting<br />
Sugar Gum retain approximately 120,000 seeds in<br />
the canopy that are released to germinate en<br />
masse after fire (Ruthrof 2001). Post-fire control of<br />
resprouting adults and seedlings is very effective<br />
for this and other species with a similar fire<br />
response. Indeed, if seedlings aren’t controlled<br />
then such species could rapidly dominate the<br />
bushland.<br />
• Seedling recruitment can be extensive. Post-fire<br />
recruitment of Acacia sophorae has been recorded<br />
as high as 32,000 seedlings per hectare (McMahon<br />
et al. 1994). A consistent effort over a few years<br />
can drastically reduce, and sometimes eliminate<br />
the population.<br />
• The fire itself may destroy a large portion of the<br />
weed seedbank. Intense fire has been shown to<br />
destroy a large proportion of the soil stored seed<br />
of Sydney Golden Wattle (Acacia longifolia)<br />
(McMahon et al. 1994), although less intense fires<br />
can result in mass recruitment.<br />
• For some species such as Victorian Tea Tree<br />
(Leptospermum laevigatum) the season in which<br />
mature trees are burnt may be critical in<br />
determining the amount of post-fire recruitment of<br />
seedlings (Molnar et al. 1989).<br />
• Whatever the scenario, funds must be available for<br />
post-fire control work or weed problems can be<br />
amplified. Other weeds, not just woody species,<br />
often have a more competitive advantage in fire<br />
disturbed communities, germinating first and<br />
smothering native species.<br />
The question is then posed ‘can fires be used as a tool<br />
to manage woody weeds?’ There is little information<br />
regarding the use of fire as an actual management tool<br />
(McMahon et al. 1994). A review of the studies that<br />
have been done highlights a lack of common pre- and<br />
post-fire measurements (Downey 1999). Obviously a lot<br />
more research on weed and ecosystem response is<br />
required before fire can be recommended as a<br />
management tool. It is also important to appreciate the<br />
potential problems associated with using fire:<br />
• Resources and commitment must be put into<br />
follow-up weed control or the problems will be<br />
exacerbated. Other weeds (especially grasses), not<br />
just woody species, often have a more competitive<br />
advantage in fire-disturbed communities,<br />
germinating early and smothering native species<br />
before they can establish.<br />
• Even in fire-adapted plant communities frequent<br />
burns can result in loss of species diversity and<br />
changes in vegetation structure.
• Detailed research into the biology of the target<br />
weed, other weeds in the area and native species<br />
is often not available.<br />
• Fires can easily get out of control damaging large<br />
tracts of bushland. In small remnants this may be<br />
disastrous for the native flora and fauna.<br />
Woody weeds and waterways<br />
Many south western Australian waterways are now<br />
inhabited by a range of woody weeds. Creeks provide<br />
favourable conditions for weed tree growth and act as<br />
a dispersal route along which propagules can float<br />
downstream. It follows that, when removing a large<br />
weed infestation from along a watercourse, you should<br />
always start your removal program at the top of the<br />
stream and move downwards. Weed control techniques<br />
themselves can contribute to the dispersal of<br />
propagules. Willows, for example, grow easily from cut<br />
pieces of branch left in the mud and can be carried to<br />
new sites by water. Therefore, it is important that all<br />
potential propagules are removed from the site.<br />
When removing woody weeds from creeks and<br />
wetlands, the risk of erosion must be a primary<br />
consideration. Erosion can be started or compounded<br />
by the removal of woody weeds from embankments.<br />
Grubbing out the roots of mature trees causes major<br />
soil disturbance and stimulates erosion in most<br />
situations. Just leaving areas of bare soil allows water<br />
to move quickly across the surface and causes<br />
significant erosion problems. Entire removal of large<br />
areas of woody weeds should be very carefully<br />
considered. Even when removing small infestations, or<br />
part of a larger infestation, bare soil should be<br />
revegetated with local species as soon as possible.<br />
Rapid replacement of vegetation cover will minimise<br />
water run-off and thus loss of topsoil.<br />
In Western Australia, if woody weeds are within 20<br />
metres of flowing waterways or swamps, restrictions on<br />
herbicide use (Chapter 8) limit control choices. Felling,<br />
which does not use herbicide and does not cause major<br />
soil disturbance, is one option. But, for many suckering<br />
species this approach may lead to an increase in the<br />
weed infestation. Roundup Biactive ® is registered in all<br />
states for use near waterways on some weeds and a<br />
minor use off-label permit (No. PER4984) approves its<br />
use in accordance with the label in aquatic situations in<br />
Western Australia. The highly targeted stem injection<br />
method, which contains herbicide within the tree, is a<br />
good option for use near waterways, especially if a nonresidual<br />
herbicide is used.<br />
Key points<br />
Clearly the woody weeds as a group have much in<br />
common when it comes to management. The following<br />
summarises the key management issues and control<br />
techniques.<br />
• Non-sprouting, non-suckering woody weeds can be<br />
felled. No herbicide is necessary.<br />
• Species that resprout but do not sucker, can be<br />
treated by the cut and paint, stem injection, or<br />
basal bark methods.<br />
Chapter 6 Trees, Shrubs and Climbers<br />
• Species that sucker should be treated by stem<br />
injection or basal bark methods whenever possible.<br />
• When using the stem injection method ensure<br />
there is an injection point below each major<br />
branch. On plants with multiple trunks each stem<br />
should be injected or sprayed. Trees should be<br />
injected when water uptake is at a maximum.<br />
Avoid stem injection during cold weather,<br />
flowering or drought.<br />
• When applying the cut and paint or stem injection<br />
method, herbicide must be applied within seconds<br />
of tissue damage. Always use a systemic, or<br />
phloem-mobile, herbicide.<br />
• Do not inadvertently spread the weed while<br />
removing branches.<br />
• When removing infestations along waterways<br />
assess the possibilities of erosion, spread and<br />
chemical contamination first.<br />
• Allocate resources for follow-up control of<br />
resprouts and germinating seedlings (after<br />
treatment and following unplanned fires).<br />
• Knowledge of tree anatomy, physiology and<br />
biology allows you to tailor your herbicide<br />
application technique and management program.<br />
• Fire can provide a major mechanism for the<br />
establishment of new populations of many species.<br />
• Fire also offers a window of opportunity to greatly<br />
reduce and possibly eradicate populations.<br />
Managing woody weed infestations is not straight<br />
forward. Depending on your reasoning, large<br />
populations could be removed slowly to minimise<br />
disturbance and allow time for bush regeneration, or<br />
removed en masse to prevent further spread of<br />
propagules. Indeed, ‘large’ depends on your<br />
perspective and the size of the area to be protected.<br />
Ideally, fruiting branches would never be taken out and<br />
the most suitable control method would be applied<br />
from the beginning. The following case studies<br />
describe how two community groups tackled their<br />
particular woody weed problem. They illustrate the<br />
need to gather as much information on the weedy<br />
plant as possible and highlight the ‘reality’ of woody<br />
weed control - the influence that residents, season and<br />
availability of labour have on the decisions made.<br />
These case studies are followed by the woody weed<br />
management table ending the discussion of weed<br />
groups. The table presents information on the biology<br />
of individual woody weed species and known control<br />
methods. The final two chapters are dedicated to<br />
describing the simple, cheap and effective approach<br />
taken to weed mapping by EWAN staff throughout this<br />
project and discuss the frequently and less frequently<br />
asked questions about herbicide use in bushland.<br />
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Chapter 6 Trees, Shrubs and Climbers Case Studies<br />
Case study 6.1 Eastern Australian natives at Blue Gum Lake<br />
The woody weed problem at Blue<br />
Gum Lake, Perth, is largely the<br />
result of misguided planting of<br />
eastern Australian natives. Sydney<br />
Golden Wattle (Acacia longifolia)<br />
and Melaleuca linariifolia (among<br />
others) were planted throughout<br />
the Swamp Banksia (Banksia<br />
littoralis) and Flooded Gum<br />
(Eucalyptus rudis) – Paperbark<br />
(Melaleuca preissiana and Melaleuca<br />
rhaphiophylla) woodlands during<br />
the 1980s and 90s. They have since<br />
seeded, quickly naturalising and<br />
spreading, particularly following<br />
fire. Their increasing presence<br />
alters plant community dynamics<br />
within this small urban remnant.<br />
Importantly, M. linariifolia was<br />
mistakenly planted as Melaleuca<br />
preissiana, a local species,<br />
highlighting the need to use locally<br />
collected seed from correctly<br />
identified species when planting in<br />
or near bushland.<br />
The distribution of both weed<br />
species was mapped by overlaying<br />
a transparent map of the tracks on<br />
an aerial photograph and walking<br />
the bushland area. As there were<br />
local species superficially similar to<br />
the weed trees flagging tape was<br />
tied to each tree allowing quick,<br />
accurate recognition of weed<br />
species. The process took four<br />
hours to complete. It was low cost<br />
and provided a record of<br />
distribution so follow-up could be<br />
effectively carried out once all large<br />
trees were removed.<br />
Management strategies differed for<br />
the two species reflecting basic<br />
differences in their biology:<br />
Acacia longifolia<br />
Shrub to small tree<br />
Does not resprout<br />
Soil stored seed<br />
Melaleuca linariifolia<br />
Small to medium tree<br />
Resprouts<br />
Stores seed in canopy<br />
Populations of both species were<br />
small and scattered, and removing<br />
them in a single effort was<br />
appropriate to prevent further<br />
spread and aid bush regeneration.<br />
The distribution of Sydney Golden Wattle • and Melaleuca linariifolia • at Blue Gum Lake, City<br />
of Melville, Western Australia.<br />
Acacia longifolia<br />
A Bushcare work day was organised<br />
through the Department of<br />
<strong>Environmental</strong> Protection’s Ecoplan<br />
program in July 1999. Volunteers<br />
assisted the Friends with the<br />
removal of 40 Sydney Golden<br />
Wattles. The trees were cut low to<br />
the ground with pruning saws and<br />
where necessary chainsaws. The<br />
branches were carried out of the<br />
bushland to be carted away by the<br />
local shire. To follow up the control<br />
effort, a Green Corps team and City<br />
of Melville Bushcare Officers took<br />
just a few hours to hand pull<br />
emergent seedlings.<br />
The following August, flowering<br />
revealed a number of other mature<br />
plants hidden amid a dense stand of<br />
leggy Golden Wreath Wattle (Acacia<br />
saligna). These were removed with<br />
the help of two delightful Japanese<br />
volunteers who were not quite sure<br />
why we were taking out this<br />
beautiful ‘native’. A thorough search<br />
of the area revealed lots of<br />
seedlings and a few more have been<br />
found and hand-pulled in the<br />
subsequent months.<br />
The job is not over. Continued local<br />
government assistance and the<br />
input of time and effort from the<br />
Friends are important for continuity<br />
of the management program.<br />
Follow-up will need to be conducted<br />
annually for at least ten years; the<br />
soil seedbank of Sydney Golden<br />
Wattle is long-lived and trees reach<br />
seed bearing age in as little as two<br />
years. Resources should be made<br />
available for seedling removal if an<br />
unplanned fire occurs. Fire will<br />
enhance seed germination and the<br />
resulting seedling flush will largely<br />
exhaust the seedbank, providing an<br />
excellent control opportunity. The<br />
subsequent regeneration of the local<br />
Flooded Gum‚ and the Golden Wreath<br />
Wattle makes the effort worth while.<br />
Melaleuca linariifolia<br />
The removal of M. linariifolia posed<br />
additional problems. Several large<br />
trees grew within the bushland, a<br />
few close to the lake shore. The<br />
removal of these would be visible to<br />
residents across the lake. Therefore,<br />
the initial step was to convince the<br />
local council that residents would<br />
find the Swamp Banksia and<br />
Flooded Gum – Paperbark<br />
woodlands behind the weed trees<br />
equally as attractive. This took<br />
some doing. By removing the weed<br />
trees, and opening up the canopy<br />
there was also a concern that bare<br />
areas would be invaded by weeds.<br />
Australian Trust for Conservation<br />
Volunteers (ATCV) assisted the<br />
Friends in the removal of the trees.<br />
The majority of the trees were large<br />
and bulky and a chainsaw was used
Chapter 6 Trees, Shrubs and Climbers Case Studies<br />
Sydney Golden Wattle growing in bushland at Blue Gum Lake . Using a hand saw to fell a Sydney Golden Wattle at Blue Gum Lake.<br />
to prune back each tree before<br />
cutting the stump low to the<br />
ground. Neat (100 %) glyphosate<br />
was immediately applied to the cut<br />
stump. To minimise damage to<br />
native vegetation, branch removal<br />
routes were carefully planned in<br />
advance for each tree. Care was<br />
taken to collect all seed-bearing<br />
branches, no matter how small, and<br />
remove them from the site. Large<br />
sections of trunk were left in the<br />
bush to rot.<br />
In all, 20 trees were removed. It took<br />
eight people six hours to do the job.<br />
The following year saw a localised<br />
flush of M. linariifolia seedlings that<br />
Case study 6.2 Removing Edible Fig (Ficus carica) from Gingin Brook<br />
In 1999 the Friends of Gingin Brook<br />
aquired funding to manage the<br />
bushland along a section of the<br />
brook. A major component was<br />
tackling various weed issues<br />
including a dense infestation of<br />
Edible Fig (Ficus carica), which was<br />
displacing the Flooded Gum<br />
(Eucalyptus rudis) and Swamp<br />
Paperbark (Melaleuca<br />
rhaphiophylla) woodland fringing<br />
the brook. Edible Fig is a<br />
resprouting, suckering species with<br />
fruit that ripen over summer. The<br />
Fig population was mapped and<br />
found to cover approximately two<br />
hectares. Isolated trees occurred<br />
elsewhere in the bushland area. The<br />
decision was made to remove the<br />
entire infestation over summer<br />
using the cut and paint technique.<br />
Although incongruent with many<br />
things said in this chapter,<br />
constraints of funding and access<br />
lay behind the decision:<br />
Short-term funding and a Green<br />
Corps crew were available for work<br />
to be done at that time.<br />
The Figs presented an impenetrable<br />
mass of branches that had to be cut<br />
out and removed in order to access<br />
the area for control of other<br />
invasive weeds such as Blackberry<br />
and Arum Lily.<br />
The infested area was dry and<br />
access was better over summer.<br />
During winter and spring the area<br />
was mostly submerged.<br />
By removing the entire population<br />
it was hoped to protect<br />
uninfested areas.<br />
In the summer of 1998 the Green<br />
Corp team and the Friends cut<br />
down, painted stumps (with 100 %<br />
Roundup Biactive ® ) and carried out<br />
over 500 Edible Fig trees from the<br />
Flooded Gum and Swamp Paperbark<br />
woodland. In the two years since,<br />
there has been some germination,<br />
resprouting and suckering of Figs,<br />
the extent of which can only be<br />
estimated. Vigilant members of the<br />
Friends pull seedlings, spray foliage<br />
with 10 % Roundup Biactive ® or drill<br />
and inject large root boles (100 %<br />
Roundup Biactive ® ) at any sign of<br />
growth. Lone trees which have<br />
since been found are treated using<br />
the drill and fill method (100 %<br />
were hand-pulled as they appeared<br />
and will continue to be removed<br />
until the soil seedbank is exhausted.<br />
Besides this flush of seedlings, the<br />
bare spaces were largely colonised<br />
by local species, specifically:<br />
Centella (Centella asiatica) and Pale<br />
Rush (Juncus pallidus).<br />
Roundup Biactive ® ). This is the<br />
simplest method and appears to<br />
achieve a high proportion of<br />
deaths. In hindsight, to minimise<br />
spread, the group would have tried<br />
to avoid removing the Fig while in<br />
fruit. But again, access to the area<br />
limited the choices.<br />
Removal of the Figs opened up the<br />
canopy and increased light became<br />
a factor. This resulted in an influx of<br />
annual and some perennial weeds<br />
including Bushy Starwort<br />
(Symphyotrichum subulatum), Rough<br />
Sowthistle (Sonchus asper), Glossy<br />
Nightshade (Solanum americanum)<br />
and Nutgrass (Cyperus species).<br />
With the hand-removal of these<br />
weeds by the Friends, the native<br />
plants Tassel Sedge (Carex<br />
fascicularis), Tall Sedge<br />
(C. appressa), Native Knotweed<br />
(Persicaria decipiens) and<br />
Waterbuttons (Cotula coronopifolia)<br />
are rapidly returning. Regeneration<br />
of the canopy species Swamp<br />
Paperbark and Flooded Gum has<br />
also been prolific.<br />
85
Chapter 6 Trees, Shrubs and Climbers Weed Management Table<br />
Trees and Shrubs<br />
86<br />
Common name Dispersal agent<br />
Seed storage and seedbank<br />
persistence<br />
Years to first<br />
flowering<br />
Vegetative<br />
regeneration<br />
strategy<br />
Acacia baileyana* Cootamundra Wattle bird, mammal, ant soil, long 2+ n (r)<br />
Wood structure<br />
Acacia dealbata* Silver Wattle bird, water soil, long 5+ s,r,l diffuse porous<br />
Acacia decurrens* Early Black Wattle water, bird soil, long r<br />
Acacia elata* Mountain Cedar Wattle n<br />
Acacia floribunda* White Sallow Wattle bird, ant soil, long s<br />
Acacia iteaphylla* Flinders Range Wattle water, bird soil, long 2 n<br />
Acacia longifolia* Sydney Golden Wattle water, bird, ant soil, long 2 n (r)<br />
Acacia melanoxylon* Blackwood bird, water soil, long 5 s,r diffuse porous<br />
Acacia microbotrya* Manna Wattle<br />
Acacia podalyriifolia* Qeensland Silver Wattle water, bird soil, long n<br />
Acacia pycnantha* Golden Wattle water, bird soil, long 3 r<br />
Ailanthus altissima Tree-of-heaven wind, water, bird 2+ s,r,l ring porous<br />
Brachychiton populneus* Kurrajong bird, mammal soil, short 8+? r diffuse porous<br />
Buddleja dysophylla<br />
Buddleja madagascariensis Butterfly Bush bird (vegetative material) no seed set recorded in Australia r,l ring porous/ diffuse porous<br />
Callistemon spp* (not local spp) Bottlebrush r<br />
Callitris columellaris Coastal Pine short s non porous<br />
Casuarina cunninghamiana* Sheoak wind canopy? soil, short 4+ n (r)<br />
Casuarina glauca* Sheoak wind canopy? soil, short 4+ s,r<br />
Chamaecytisus palmensis Tagasaste explosive soil, long 3 r<br />
Chrysanthemoides monilifera Bitou Bush bird, water, mammal, ant soil, medium/long 1.5 r,l<br />
Cotoneaster spp Cotoneaster bird soil, short? 2 r<br />
Erica baccans Berry Flower Heath wind, water soil, medium 3+ r<br />
Erythrina x sykesii Flame Tree no viable seed produced? s,r,l diffuse porous<br />
Eucalyptus botryoides* Bangalay wind canopy? soil, short r diffuse porous<br />
Eucalyptus camaldulensis** River Red Gum wind canopy? soil, short r diffuse porous<br />
Eucalyptus citriodora* Lemon Scented Gum wind canopy? soil, short r diffuse porous<br />
Eucalyptus cladocalyx* Sugar Gum explosive, wind, water canopy, soil, short r diffuse porous<br />
Eucalyptus conferruminata** Bald Island Marlock wind canopy? soil, short r<br />
Eucalyptus globulus* Tasmanian Bluegum wind canopy? soil, short r diffuse porous<br />
Eucalyptus maculata* Spotted Gum wind canopy? soil, short r diffuse porous<br />
Eucalyptus muelleriana* Yellow Stringybark wind canopy? soil, short r diffuse porous<br />
Eucalyptus polyanthemos* Red Box wind canopy? soil, short r diffuse porous<br />
Eucalyptus saligna* Sydney Bluegum wind canopy? soil, short r diffuse porous<br />
Ficus carica Edible Fig bird, mammal short? 4+ s,r,l diffuse porous<br />
Genista spp Broom explosive, bird, water soil, long 2 r<br />
Gomphocarpus fruticosus Narrowleaf Cottonbush wind, water soil,long 2 s,r<br />
Hibiscus diversifolius* Swamp Hibiscus short 1 s,r<br />
Lagunaria patersoniana* Norfolk Island Hibiscus short n<br />
*Eastern Australian natives naturalised in Western Australia. **Western Australian natives that have become weedy when planted outside their natural range.<br />
Dispersal: mode of seed dispersal Seedbank: main storage of seed (canopy or soil), and length of seed viability, short = days to 1 year, medium = 1-5 years,<br />
long = 5 years plus. Years to maturity: years to first seed crop. Regeneration strategy: r = coppices/resprouts, l = stem layering, n = not sprouting or suckering,<br />
s = suckers (parentheses indicate occasional occurrence has been observed). Management and control: Injection = drill and fill or frilling
Chapter 6 Trees, Shrubs and Climbers Weed Management Table<br />
Suggested method of management and control References<br />
Hand pull seedlings; fell mature plants, young plants may occasionally resprout. Basal bark - picloram/triclopyr. 58, 167, 231, 319, 51, 228, 242, 222<br />
Hand pull seedlings; basal bark - picloram/triclopyr (autumn). 53, 58, 167, 319, 228, 242<br />
Hand pull seedlings; basal bark - picloram/triclopyr (autumn); cut and paint - neat glyphosate. 53, 167, 231, 319, 228, 242<br />
Hand pull seedlings; fell mature plants. Resprouting has been recorded in some areas - if in doubt basal bark spray with triclopyr/picloram. 58, 167, 242<br />
Hand pull seedlings; try injection - 50 % glyphosate or basal bark - picloram +triclopyr. 167, 60, 242<br />
Hand pull seedlings; fell mature plants. 58, 167, 242<br />
Hand pull seedlings; fell mature plants, young plants may occasionally resprout. Basal bark - picloram/triclopyr. 53, 58, 167, 319, 228, 242<br />
Hand pull seedlings; try injection - 50 % glyphosate or basal bark - picloram/triclopyr (autumn). 53, 58, 167, 319, 228, 242, 222<br />
Hand pull seedlings; fell mature plants. 58, 167, 319, 242<br />
Hand pull seedlings; basal bark - picloram/triclopyr (autumn); cut and paint - 100 % glyphosate or picloram/triclopyr. 53, 134, 319, 228, 242<br />
injection 100 % glyphosate; basal bark - picloram/triclopyr (summer). 10, 30, 167, 248, 303, 320, 51, 242<br />
Hand pull seedlings; try injection with 50-100 % glyphosate or basal bark - picloram/triclopyr; cut and paint - glyphosate. 48, 167, 242<br />
Hand pull small plants - remove all stem material. 167, 242<br />
Hand pull small plants - remove all stem material. 167, 241, 297, 242<br />
Hand pull seedlings; try cut and paint with 50-100 % glyphosate. 167, 242<br />
Try cut and paint with 100 % glyphosate; injection in this species with non porous wood may be ineffective. 124, 242<br />
Hand pull seedlings;fell mature plants; cut and paint young plants - 50 % glyphosate. 167, 241, 291, 242<br />
Hand pull seedlings; basal bark - Garlon ® +oil; try drill and fill - 50 % glyphosate. 21, 114, 167, 241, 291, 242<br />
Hand pull seedlings where possible; basal bark - picloram/triclopyr; foliar spray with 0.5 g/10 L metsulfuron methyl + Pulse ® . 167, 231, 313, 228, 242<br />
Hand pull small plants to 1m; cut and paint or inject 100 % glyphosate or foliar spray with 1 % glyphosate (spr-sum). 9, 21, 95, 167, 231, 248, 285, 327, 313, 2, 242<br />
Seedlings difficult to hand pull; cut and paint with 40-100 % glyphosate or foliar spray - glyphosate + metsulfuron methyl (Trounce ® ) (spr-sum). 21, 167, 231, 51, 242<br />
Digout small plants; cut and paint - 20 % glyphosate (aut-win); slash prior to seed set, spray regrowth within year - 1 % glyphosate. 21, 231, 242<br />
Injection - closely spaced holes/frills or try basal bark- picloram/triclopyr. 9, 167, 242<br />
Hand pull seedlings; try cut and paint or inject root crown - 50 % glyphosate; foliar spray regrowth - 1.5 % glyphosate. 134, 167, 231, 319, 242<br />
Hand pull seedlings; try cut and paint or inject root crown - 50 % glyphosate; foliar spray regrowth - 1.5 % glyphosate. 167, 242<br />
Hand pull seedlings; try cut and paint or inject root crown - 50 % glyphosate; foliar spray regrowth - 1.5 % glyphosate. 167, 231, 242<br />
Hand pull seedlings; try cut and paint or inject root crown - 50 % glyphosate; foliar spray regrowth - 1.5 % glyphosate. 167, 231, 282, 242<br />
Hand pull seedlings; try cut and paint or inject root crown - 50 % glyphosate; foliar spray regrowth - 1.5 % glyphosate. 167, 242<br />
Hand pull seedlings; try cut and paint or inject root crown - 50 % glyphosate; foliar spray regrowth - 1.5 % glyphosate. 167, 231, 242<br />
Hand pull seedlings; try cut and paint or inject root crown - 50 % glyphosate; foliar spray regrowth - 1.5 % glyphosate. 167, 242<br />
Hand pull seedlings; try cut and paint or inject root crown - 50 % glyphosate; foliar spray regrowth - 1.5 % glyphosate. 167, 242<br />
Hand pull seedlings; try cut and paint or inject root crown - 50 % glyphosate; foliar spray regrowth - 1.5 % glyphosate. 167, 242<br />
Hand pull seedlings; try cut and paint or inject root crown - 50 % glyphosate; foliar spray regrowth - 1.5 % glyphosate. 167, 242<br />
Hand pull seedlings; inject with 50-100 % glyphosate (summer); foliar spray regrowth with 10 % glyphosate or inject root boles. 167, 242<br />
Hand pull small seedlings; cut and paint - 100 % glyphosate or foliar spray - 1 % glyphosate, repeat treatment (win-spr). 53, 134, 163, 231, 248, 344, 242<br />
Hand pull small plants; foliar spray with 1.5 % glyphosate or try cut and paint - 50 % glyphosate (Sep-Dec). 248, 242<br />
Hand pull seedlings; fell mature plants. 167, 242<br />
167, 242<br />
124, 242<br />
87
Chapter 6 Trees, Shrubs and Climbers Weed Management Table<br />
Common name Dispersal agent<br />
Seed storage and seedbank<br />
persistence<br />
Years to first<br />
flowering<br />
Vegetative<br />
regeneration<br />
strategy<br />
Lantana camara Lantana bird, mammal, water 2+ s,r,l<br />
Lavandula stoechas Lavender r<br />
Leonotis leonurus Lion's Tail s<br />
Leptospermum laevigatum* Victorian Tea Tree wind soil short, canopy 4 n (r) l<br />
Lycium ferocissimum African Boxthorn bird, mammal, water (skinks) soil, short? 2 s,r,l<br />
Melaleuca lanceolata** wind, water canopy, long/soil, short r<br />
Melaleuca linariifolia* wind, water canopy, long/soil,short r<br />
Melaleuca quinquenervia* Cajeput wind, water canopy, long/soil, short 3 r (l)<br />
88<br />
Wood structure<br />
Melia azedarach** Cape Lilac bird, water soil, short/medium 3? s,r,l semi ring porous<br />
Nicotiana glauca Tobacco Tree wind, water soil, ? 1 s,r,l<br />
Olea europea Olive bird, mammal soil, long 5+ s,r diffuse porous<br />
Pinus pinaster Maritime Pine wind canopy, medium 7 n (r) non porous<br />
Pinus radiata Radiata Pine wind canopy, medium 5+ n (r) non porous<br />
Pittosporum undulatum* Sweet Pittosporum bird, mammal soil, short/medium 5 r diffuse porous<br />
Polygala myrtifolia Butterfly Bush bird, ant, water soil, short/medium 3 n<br />
Populus alba White Poplar wind, water none? short? s,r,l diffuse porous<br />
Populus nigra Lombardy Poplar no viable seed produced? s,r,l diffuse porous<br />
Psoralea pinnata Taylorina bird, mammal, water soil, long (8) -1 (r)<br />
Rhamnus alaternus Buckthorn bird, mammal soil, long 2? r<br />
Ricinus communis Castor Oil Plant water, mammal, explosive soil, medium 1+ r<br />
Robinia pseudoacacia Black Locust ? seedlings rare 6+ s,r ring porous<br />
Rosa laevigata Cherokee Rose bird, mammal soil, medium 3 s,r,l<br />
Rubus spp Blackberry bird, mammal, water soil, short 2 s,r,l<br />
Salix babylonica Willow wind, water short (no female trees in W.A?) 4+ s,r,l diffuse porous<br />
Schinus terebinthifolius Brazilian Pepper bird, water short 3 s,r<br />
Solanum aviculare* Kangaroo Apple bird, mammal soil, long 2+ s,r<br />
Solanum laciniatum Kangaroo Apple s,r<br />
Tamarix spp Athel Pine, Tamarisk wind, bird, mammal short 3 s,r ring porous<br />
Ulmus procera English Elm fruit usually sterile<br />
Washingtonia filifera Cotton Palm mammal, bird soil, short/medium 9+ n<br />
Vines<br />
Anredera cordifolia Madeira Vine water aerial & underground tubers na r<br />
Asparagus asparagoides Bridal Creeper See chapter 4 - Corms, Bulbs and Tubers<br />
Cardiospermum grandiflorum Large Balloon Creeper water, wind soil, short r<br />
Dipogon lignosus Dolichos Pea explosive, bird, water soil, medium 2+ r<br />
Ipomoea carica Morning Glory wind, water r,l<br />
Ipomoea indica Purple Morning Glory water (stolons) r,l<br />
Lonicera japonica Japanese Honeysuckle bird, mammal, water s,r,l<br />
Parthenocissus quinquefolia Virginia Creeper ant, bird soil, short-medium r,l<br />
Senecio tamoides Canary Creeper wind, water s<br />
*Eastern Australian natives naturalised in Western Australia. **Western Australian natives that have become weedy when planted outside their natural range.<br />
Dispersal: mode of seed dispersal Seedbank: main storage of seed (canopy or soil), and length of seed viability, short = days to 1 year, medium = 1-5 years,<br />
long = 5 years plus. Years to maturity: years to first seed crop. Regeneration strategy: r = coppices/resprouts, l = stem layering, n = not sprouting or suckering,<br />
s = suckers (parentheses indicate occasional occurrence has been observed). Management and control: Injection = drill and fill or frilling<br />
s
Suggested method of management and control References<br />
Basal bark- triclopyr/picloram (sum-aut) or cut stump; foliar spray regrowth with 1.5 % glyphosate; biological control. 29, 95, 231, 248, 295, 301, 242<br />
Hand pull small plants; try cut and paint with 50 % glyphosate.<br />
Chapter 6 Trees, Shrubs and Climbers Weed Management Table<br />
Handpull seedlings or small plants. 328, 242<br />
Hand pull seedlings; fell mature plants. Resprouting has been recorded in some areas - if in doubt basal bark spray with triclopyr+picloram. 50, 123, 218, 319, 228, 191, 242<br />
Injection - neat glyphosate; or basal bark with triclopyr/picloram (Feb-May); foliar spray regrowth with 10 % glyphosate or 1 % Grazon ® + Pulse ® . 95, 231, 248, 313, 342, 228, 242, 222<br />
Hand pull seedlings; cut and paint - 50 % glyphosate. 242<br />
Hand pull seedlings; cut and paint - 50 % glyphosate. 242<br />
Hand pull seedlings; cut and paint - 100 % glyphosate (basal bark ineffective). 29, 75, 241, 302, 242<br />
Hand pull seedlings; injection - neat glyphosate; basal bark - 10 % triclopyr (summer). 20, 241, 319, 242<br />
242<br />
167, 319, 242<br />
Hand pull seedlings; basal bark - triclopyr or try injecting into root crown - glyphosate (sum-aut); foliar spray regrowth - 1.5 % glyphosate. 7, 4, 231, 248, 242<br />
Hand pull seedlings; fell mature plants; cut and paint young plants - try 50 % glyphosate. 21, 167, 231, 319, 242<br />
Hand pull seedlings; fell mature plants; cut and paint young plants - try 50 % glyphosate. 21, 82, 167, 231, 319, 313, 242<br />
Hand pull seedlings; cut and paint, injection - 50 % glyphosate (young plants killed by fire/slashing). 29, 134, 135, 167, 231, 279, 278, 142, 242, 230b<br />
Hand pull seedlings - dense stands can be sprayed with 1.5 % glyphosate; fell mature plants. 21, 167, 231, 228, 242<br />
Basal bark - 25 % triclopyr; injection - 70 % glyphosate; foliar spray regrowth. 81, 167, 272, 51, 242<br />
Basal bark - 25 % triclopyr; injection - 70 % glyphosate; foliar spray regrowth. 81, 167, 51, 242<br />
Hand pull seedlings (slash dense clumps); hand pull young plants 1- 2 years old, cut and paint - 20 % glyphosate or foliar spray 1 g/10 L metsulfuron methyl + Pulse ® ;<br />
fell mature plants.<br />
21, 134, 167, 231, 228, 242<br />
Hand pull seedlings; cut and paint - neat glyphosate; injection - Grazon®; foliar spray regrowth - 1.5 % glyphosate (autumn). 21, 79, 167, 231, 242<br />
Hand pull seedlings; cut or scrape and paint - 50 % glyphosate; basal bark - triclopyr or Garlon ® (spr-sum). 9, 95, 134, 167, 231, 242<br />
Hand pull seedlings; basal bark - picloram/triclopyr (spr-sum): Intolerant of shade. 80, 167, 299, 304, 14, 242<br />
Hand pull seedlings; basal bark - triclopyr (Dec). 167, 231, 248, 242<br />
Hand pull small plants; cut and paint or slash canes and spray regrowth at 0.5 metres with metsulfuron methyl 1 g/10 L (sum-aut). Will require follow up for a number<br />
of years.<br />
3, 21, 95, 167, 231, 241, 248, 47, 51, 343, 228, 242<br />
Hand pull seedlings; injection - 50 % glyphosate (check restrictions on chemical use near waterways) (sum-aut). 4, 21, 167, 231, 319, 181, 242, 269<br />
Hand pull seedlings; injection - 50 % glyphosate; basal bark - triclopyr/picloram. (summer). 76, 113, 167, 125, 167, 231, 245, 246, 248, 242, 39<br />
Hand pull small plants; injection - 50 % glyphosate (sum-aut); basal bark with 1.5 % triclopyr/picloram. 167, 228, 242<br />
Hand pull small plants; injection - 50 % glyphosate (sum-aut); basal bark with 1.5 % triclopyr/picloram. 167, 228, 242<br />
Injection into root crown - neat glyphosate; cut and paint - 30 % triclopyr; basal bark or spray regrowth (autumn). 167, 215, 232, 248, 306, 242<br />
Try injection with 50 % glyphosate or basal bark spray - picloram/triclopyr. 324, 242<br />
Hand pull seedlings; chop off at base when not in fruit. 164, 167, 242<br />
Stem scrape or drill and fill thick vines - 100 % glyphosate (Do not cut the stem); intensive follow up of resprouts at 2-4 leaf stage. 9, 21, 167, 231, 242<br />
Hand pull small plants; sever stems, scrape and paint - 100 % glyphosate or foliar spray - glyphosate 1.5 %. 9, 167, 231, 242<br />
Hand pull small plants ensuring removal of all root material; scrape and paint - 100 % glyphosate or foliar spray in highly degraded sites with 1.5 % glyphosate. 21, 167, 231, 228, 242, 233<br />
Hand pull seedlings; scrape and paint stem - 20 -100 % glyphosate. 9, 21, 167, 231, 241, 242<br />
Scrape and paint stem- 20-50 % glyphosate. 9, 21, 167, 231, 241, 242<br />
Hand pull seedlings; scrape and paint stems - 100 % glyphosate; spray regrowth 1.5 % glyphosate. 9, 21, 74, 238, 241, 320, 51, 340, 242<br />
Hand pull seedlings; scrape and paint stems - 100 % glyphosate; spray regrowth 1.5 % glyphosate. 73, 319, 242<br />
Try 1 % glyphosate or Lontrel ® 20 mL/ 10 L + wetting agent. 328, 242, 222<br />
242<br />
242<br />
89
90<br />
Chapter 7 Weed Mapping in<br />
Remnant <strong>Bushland</strong><br />
Mapping of individual weed species is an important<br />
step in setting priorities for weed control work in small<br />
reserves. Throughout the course of the project, EWAN<br />
has often been asked to participate in workshops,<br />
informing people on how to map weeds in bushland. To<br />
facilitate this process some mapping guidelines were<br />
drafted. This chapter is a revision of those guidelines<br />
and is designed to provide a step by step guide to weed<br />
mapping in urban bushland.<br />
Equipment required<br />
Aerial photograph of bushland<br />
Aerial photographs are easily obtained from the<br />
Department of Land Administration (DOLA). It is<br />
important to know the date the photograph was taken<br />
and the scale of the photograph.<br />
When weed mapping, it is practical to enlarge the image<br />
of the bushland reserve to A4 so it can be used with a<br />
standard clipboard. An aerial photograph of the 21<br />
hectare Shenton <strong>Bushland</strong> fits onto an A4 sheet at a<br />
scale of 1:16000, while Talbot Road <strong>Bushland</strong><br />
(60 hectares) fits at a scale of 1:60000. However, fitting a<br />
reserve larger than Talbot Road <strong>Bushland</strong> to an A4<br />
sheet would result in loss of detail making it difficult to<br />
accurately map weed distribution.<br />
Figure 1. A map of Shenton <strong>Bushland</strong> was photocopied onto a clear<br />
overlay and adjusted to fit the aerial photograph. The distribution of<br />
Freesia • across the bushland was then mapped.<br />
Map of bushland tracks<br />
Sometimes the major tracks and features of a reserve<br />
have been mapped as part of a management plan. This<br />
map can be photocopied onto a clear overlay and the<br />
size adjusted to fit the aerial photo (Figure 1). Tracks<br />
and other features marked on the overlay provide<br />
reference points in the bushland.<br />
Other Items<br />
Clip board<br />
Waterproof, permanent marking pens (medium tip)<br />
Compass (can be useful)<br />
What weeds to map?<br />
It is not necessary to map all the weeds in a bushland<br />
patch. Some weeds may have very little impact on the<br />
native plant communities (Box 7.1). In Banksia<br />
woodland, many annual herbs and grasses fall into this<br />
category e.g. Ursinia anthemoides, Aira caryophyllaceus.<br />
Start by mapping five or six of the most serious<br />
perennial weeds. To determine these:<br />
Consider site-specific issues. Which weeds are<br />
moving into, or have the potential to move into,<br />
undisturbed bushland? What impact does a<br />
particular weed have on the native plant<br />
communities?<br />
Consult existing management plans (if available)<br />
and look at the weeds listed in the <strong>Environmental</strong><br />
<strong>Weeds</strong> Strategy for Western Australia (Department<br />
of Conservation and Land Management 1999).<br />
Visit the site throughout the year to determine what<br />
and where the serious weeds are. At Blue Gum Lake<br />
bushland, Paspalum (Paspalum urvillei) and Sydney<br />
Golden Wattle (Acacia longifolia) are the most<br />
obvious weeds over summer. In late autumn<br />
Soursob (Oxalis pes-caprae) and Annual and<br />
Perennial Veldgrass (Ehrharta longiflora, E. calycina)<br />
start to dominate. By winter, Freesia (Freesia alba x<br />
leichtlinii) and Yellow Soldier (Lachenalia reflexa)<br />
are obvious, often in undisturbed areas.<br />
Box 7.1 Criteria used in the<br />
<strong>Environmental</strong> <strong>Weeds</strong> Strategy for Western<br />
Australia to assess weeds in terms of their<br />
impact on biodiversity<br />
Invasiveness: Ability to invade bushland in good<br />
to excellent condition or ability of weeds to invade<br />
waterways.<br />
Distribution: Current or potential distribution<br />
including consideration of known history of widespread<br />
distribution elsewhere in the world.<br />
<strong>Environmental</strong> impact: Ability to change the<br />
structure, composition and function of an ecosystem.<br />
In particular an ability to form a monoculture<br />
in a vegetation community.<br />
Source: Department of Conservation and Land<br />
Management (1999)
Chapter 7 Weed Mapping in Remnant <strong>Bushland</strong><br />
Mapping in practice<br />
It is simplest to map one weed at a time. If a small<br />
group of people are present, colour photocopies of the<br />
aerial photograph can be provided so that each person<br />
can map a different weed. Before mapping begins,<br />
place a label on the bottom corner of the overlay and<br />
write the date, the name of the weed being mapped<br />
and those people participating in the mapping<br />
exercise. The date is essential if the map is to be used<br />
as a monitoring tool.<br />
Traversing the bushland<br />
Start at one edge of the bushland and walk across the<br />
site at regular, parallel, intervals. The intervals can be<br />
around 10 to 50 metres apart depending on the<br />
vegetation type and the visibility of the weed. A<br />
compass may be helpful. If the site is disected by<br />
paths, mapping within the sections of bushland<br />
created, can be more accurate.<br />
Marking weed populations on the map<br />
Many weeds occur in discrete clumps. Mark the<br />
location and spread (using the map scale as a guide to<br />
size) of the weed population on the map. Features on<br />
the overlay and aerial photograph (tracks, water<br />
bodies, vegetation boundaries, isolated trees and the<br />
roofs of houses adjacent to bushland) can be used to<br />
pinpoint the location of weed populations. Most<br />
serious weeds can be mapped in this way including<br />
bulbous, cormous and tuberous species like Watsonia<br />
(Watsonia meriana), Arum Lily (Zantedeschia<br />
aethiopica), Bridal Creeper (Asparagus asparagoides)<br />
and Freesia, woody weeds including weedy Acacias<br />
and Blackberry (Rubus fruticosus) and some grass<br />
weeds like African Lovegrass (Eragrostis curvula).<br />
Mapping cover<br />
Weed cover can also be mapped. Changes in cover<br />
over time can provide information on the success of a<br />
control program, increase or decrease in weed<br />
numbers or vigour and can give an indication of where<br />
to start control works. To map cover, different symbols<br />
or different colors can be used to represent cover<br />
classes. For example:<br />
Light infestation 1-10 % of ground cover (green)<br />
Light-medium 11-30 % (blue)<br />
Medium-heavy 31-70 % (orange)<br />
Heavy >70 % (red)<br />
Mapping weed cover can be subjective but is often the<br />
only practical method of recording weed species that<br />
are spread throughout bushland in varying densities<br />
such as Perennial Veldgrass (Ehrharta calycina). Kings<br />
Park developed a system for mapping Veldgrass by<br />
estimating cover within a series of 50 m grids across<br />
the bushland (Bob Dixon unpublished data). This<br />
method was used at Blue Gum Lake (case study 3.4)<br />
and at Shenton <strong>Bushland</strong> (Box 7.3). The usefulness and<br />
practicalities of mapping weeds in this way will depend<br />
on the size of your reserve and the patchiness of the<br />
weed’s distribution.<br />
Weed mapping along creeks and waterways<br />
It can be difficult to use aerial photographs to map<br />
along waterways as a dense overstorey of fringing<br />
vegetation often obscures recognisable features below.<br />
At Gingin Brook an aerial photograph was used to<br />
produce a scale mud map (Figure 2). The area along the<br />
brook was then walked and all the major weeds were<br />
mapped. The result is not as detailed as the maps<br />
mentioned previously but still helps in setting priorities<br />
and monitoring the success of control programs.<br />
Virginia Creeper<br />
Castor Oil Bush<br />
Honeysuckle<br />
Canna Lily<br />
Morning Glory<br />
Taro<br />
Blackberry<br />
Edible Fig<br />
Brazilian Pepper<br />
Arum Lily<br />
Para Grass<br />
Kurrajong<br />
Olive<br />
Reed Sweet Grass<br />
Figure 2. Mud map showing generalised distribution of weeds along<br />
Gingin Brook.<br />
Using weed maps<br />
Protecting the good bushland: Maps of individual<br />
weed species enable targeted control work and<br />
protection of priority areas from weed invasion. By<br />
overlaying maps of individual weed species onto a<br />
bushland condition map (Chapter 2, Box 2.1, Box 7.2)<br />
weed control strategies can be developed that aim to<br />
protect the least disturbed bushland. For example,<br />
small isolated patches of serious weeds in relatively<br />
undisturbed bushland can be identified and listed as a<br />
high priority for control.<br />
Understanding the distribution of weeds in bushland:<br />
Overlaying weed maps onto vegetation maps can<br />
highlight relationships between weed species and<br />
particular plant communities. For example, Tribolium<br />
(Tribolium uniolae) distribution in the Brixton Street<br />
Wetlands is clearly associated with Marri woodlands and<br />
drier shrublands or the soil types these communities<br />
91
92<br />
Chapter 7 Weed Mapping in Remnant <strong>Bushland</strong><br />
occupy. At Quairading Nature Reserve the distribution of<br />
the Wild Oat (Avena barbata) is clearly associated with<br />
the soils of the York Gum (Eucalyptus loxophleba) – Jam<br />
(Acacia acuminata) woodlands (Chapter 5, Box 5.2).<br />
Monitoring the spread of established weeds and the<br />
effectiveness of control programs: Weed maps<br />
provide a useful tool for monitoring the establishment<br />
and spread of weeds. Mapping weed distribution and<br />
Box 7.2 Vegetation condition maps<br />
cover prior to beginning any control program and then<br />
in subsequent years will provide an indication of the<br />
program’s effectiveness (Box 7.3). If no control is being<br />
undertaken then maps can provide general information<br />
on the rate of spread over time and whether or not a<br />
particular weed is moving away from disturbed areas<br />
into good bushland. Weed maps can also highlight the<br />
main direction of spread - along tracks, with prevailing<br />
winds or in sheet water flow.<br />
Vegetation condition maps illustrate how different degrees of disturbance are distributed throughout a<br />
particular bushland site and are a useful tool for developing management strategies. There are a two condition<br />
scales used in Western Australia (Kaesehagen 1994, Keighery 1994). Mapping of vegetation condition requires<br />
an understanding of the effects different types of disturbance may have on bushland, a knowledge of native<br />
flora and familiarity and understanding of what a particular undisturbed plant community would be like.<br />
Table 1 Vegetation Condition Scale Table 2. <strong>Bushland</strong> Condition Scale<br />
(Keighery 1994) (Kaesehagen 1994)<br />
Vegetation Condition Scale<br />
1 = ‘Pristine’<br />
Pristine or nearly so, no obvious signs of disturbance.<br />
2 = Excellent<br />
Vegetation structure intact, disturbance affecting individual<br />
species and weeds are non-aggressive species.<br />
For example, damage to trees caused by fire, the presence of<br />
non-aggressive weeds and occasional vehicle tracks.<br />
3 = Very Good<br />
Vegetation structure altered, obvious signs of disturbance.<br />
For example, disturbance to vegetation structure caused by<br />
repeated fires, the presence of some more aggressive weeds,<br />
dieback, logging and grazing.<br />
4 = Good<br />
Vegetation structure significantly altered by very obvious signs<br />
of multiple disturbance. Retains basic vegetation structure or<br />
the ability to regenerate it.<br />
For example, disturbance to vegetation structure caused by<br />
very frequent fires, the presence of some very aggressive<br />
weeds, partial clearing, dieback and grazing.<br />
5 = Degraded<br />
Basic vegetation structure severely impacted by disturbance.<br />
Scope for regeneration but not to a state approaching good<br />
condition without intensive management.<br />
For example, disturbance to vegetation structure caused by<br />
very frequent fires, the presence of some very aggressive<br />
weeds, partial clearing, dieback and grazing.<br />
6 = Completely Degraded<br />
The structure of the vegetation is no longer intact and the area<br />
is completely or almost completely without native species.<br />
These areas are often described as ‘parkland cleared’ with the<br />
flora comprising weed or crop species with isolated native<br />
trees or shrubs.<br />
Very Good - Excellent<br />
• 80-100 % Native Flora<br />
Composition<br />
• Vegetation structure intact or<br />
nearly so<br />
• Cover /abundance of weeds<br />
less than 5%<br />
• No or minimal signs of<br />
disturbance<br />
Fair to Good<br />
• 50-80 % Native Flora<br />
Composition<br />
• Vegetation structure modified or<br />
nearly so<br />
• Cover/abundance of weeds<br />
5-20 % any number of individuals<br />
• Minor signs of disturbance<br />
Poor<br />
• 20-50 % Native Flora<br />
Composition<br />
• Vegetation structure completely<br />
modified<br />
• Cover/abundance of weeds 20-<br />
60 % any number of individuals<br />
• Disturbance incidence high<br />
Very Poor<br />
• 0-20 % Native Flora Composition<br />
• Vegetation structure<br />
disappeared<br />
• Cover/abundance of weeds 60-<br />
100 % any number of individuals<br />
• Disturbance incidence very high
Chapter 7 Weed Mapping in Remnant <strong>Bushland</strong><br />
Box 7.3 Using maps to monitor change and set priorities at Shenton <strong>Bushland</strong><br />
Over the past four years a contractor has been employed to spray the Perennial Veldgrass (Ehrharta calycina)<br />
at Shenton <strong>Bushland</strong>. Perennial Veldgrass cover was mapped over the period using the method devised by Bob<br />
Dixon at Kings Park. Annual mapping provided a measure of effectiveness for the Perennial Veldgrass control<br />
program over time.<br />
Perennial Veldgrass populations were mapped each May prior to spraying in winter. The maps reflected the<br />
success of the previous year’s control program and were used for allocating the limited resources to priority<br />
areas in the current year. The project began with an $8000 grant to the Friends from the Lotteries commision in<br />
1998. A fire had burnt through the central section of the bushland in October 1997. The Friends used the grant<br />
money to spray a 12 hectare section of unburnt bushland. By 1999 it became clear (with the help of maps) that<br />
the money should have been directed into the burnt areas. From 1999 onwards the Veldgrass populations were<br />
mapped each year and resources allocated accordingly.<br />
1999 Resources available: $2000 grant to the Friends of Shenton <strong>Bushland</strong> from the Lotteries Commission,<br />
$6000 from Nedlands City Council. Directed to the central bushland area where dense infestations (in red) had<br />
established in good to excellent condition bushland following fire in October 1997.<br />
2000 Resources available: $3500 Community Conservation Grant to the Friends and $6500 from the Nedlands<br />
City Council. The previous year’s work in the good condition bushland was followed up, leaving the dense<br />
infestations around the edges of the bushland until more resources became available.<br />
2001 Resources available: $6000 from Nedlands City Council. With Perennial Veldgrass now at less than 5 %<br />
cover over much of the bushland in good to excellent condition, resources were redirected to the degraded<br />
edges. The dense infestations in these areas were a fire hazard and a seed source capable of re-infesting the<br />
rest of the bushland.<br />
2002 Resources available: $6000 from City of Nedlands and $7000 from Swan Catchment Urban Landcare<br />
Program. Perennial Veldgrass cover across much of the bushland down to around 5 %. Enough resources to do<br />
follow-up work across the bushland excluding the central area.<br />
1999 2000 2001 2002<br />
• 60 - 100% • 5 - 59% •
94<br />
Chapter 8 Herbicide Use<br />
in <strong>Bushland</strong><br />
The issue of herbicide use in bushland is sometimes a<br />
sensitive one. This chapter aims to give the reader a<br />
greater understanding of herbicides, their fate in the<br />
environment and the legislation regarding their use.<br />
It sometimes does this by directing the reader to<br />
alternate sources of information. The role of spray<br />
contractors in bushland regeneration is also discussed<br />
and some basic information given on the herbicides<br />
mentioned throughout this manual.<br />
Using herbicides in bushland<br />
Many professional bush regenerators and members of<br />
community groups are uncomfortable with the use of<br />
herbicides in bushland, others actively oppose it.<br />
Nevertheless, herbicide use in bushland management<br />
appears to have increased in recent times. Bush<br />
regenerators try to use herbicides only in very targetspecific<br />
situations: The injection of herbicide into the<br />
trunk of trees, spot spraying individual grass clumps<br />
with selective herbicide or the wiping of leaf blades for<br />
cormous species like Watsonia. It is often a choice<br />
between the minimal damage done by carefully targeted<br />
herbicides and the loss of animal and plant biodiversity<br />
caused by dense invasions of weeds. When applied<br />
carefully by trained personnel with a detailed<br />
knowledge of herbicides and of the flora and bushland<br />
they are working in, herbicides can be an invaluable<br />
weed management tool:<br />
• Herbicides can control more weeds more quickly and<br />
with less labour than appropriate physical methods.<br />
• They cause fewer physical disturbances to the soil<br />
and surrounding vegetation - limiting erosion and<br />
reducing the creation of microsites for germination<br />
of other weed species.<br />
• They avoid the carrying of weed material through<br />
good condition bushland, decreasing the dispersal<br />
of seeds and reproductive propagules.<br />
• Grass-selective herbicides are available that cause<br />
little or no damage to species not of the grass<br />
(Poaceae) family.<br />
• Broad-spectrum herbicides can be applied<br />
selectively to the target plant.<br />
Duty of care<br />
Before using herbicides in bushland, or employing<br />
someone else to use them for you, personal safety of<br />
the applicator and others in the area need to be<br />
considered.<br />
People who use herbicides in bushland, including<br />
volunteers, have a ‘duty of care’ to the environment,<br />
members of the public and themselves. A clear,<br />
informative explanation of the section in the<br />
Occupational Safety and Health Act 1984 involving<br />
chemicals in the workplace and working with<br />
pesticides, is available online at http://www.safetyline.wa.<br />
gov.au/pagebin/hazshazd0018.htm. Briefly:<br />
• Applicators (including volunteers) should have<br />
appropriate training in the safe storage, handling,<br />
preparation and use of any herbicide they use.<br />
• Current Material Safety Data Sheets (MSDS) must<br />
be on hand and available for perusal by any<br />
persons coming in contact with the herbicide.<br />
• The public should be made aware of any chance<br />
they may come into contact with a chemical.<br />
• All hazardous substances kept on the premises<br />
should be named in a poisons register and the<br />
associated MSDS stored with them.<br />
• Herbicides should be transported and stored safely.<br />
• Herbicides must be labelled correctly. It is an<br />
offence to permanently store registered herbicides<br />
in anything other than their original containers<br />
with their original labels. Temporary containers<br />
must be labelled with the product name and the<br />
appropriate risk and safety phrases.<br />
• Information and training should be provided to<br />
group members on potential health risks and toxic<br />
effects, control measures, correct use of control<br />
methods and correct care and use of personal<br />
protective equipment and clothing.<br />
Personal care<br />
The application of herbicides involves a high degree of<br />
personal care. Long-term effects of most herbicides are<br />
unknown and it is safest to avoid contamination.<br />
Herbicide labels carry a protective equipment list that<br />
identifies the minimum safety requirements. Protective<br />
equipment should be worn during:<br />
• Mixing of herbicides.<br />
• Application.<br />
• Entering a treated area before the herbicide has<br />
dried or dissipated.<br />
• Further steps that aid in personal hygiene are<br />
listed in Box 8.1.<br />
In Australia a poisons schedule system is in place. The<br />
schedule number indicates the level of toxicity of the<br />
chemical to humans and the precautions that should<br />
be taken. The poisons schedule does not give an<br />
indication of danger to the environment. All<br />
pesticides, including herbicides, are classed as either<br />
S5, S6, S7 or exempt from scheduling, depending on<br />
their degree of hazard:<br />
• Exempt from scheduling – pesticides that present<br />
little hazard in their use. Non-toxic.<br />
• Schedule 5 (domestic poisons) – poisons that<br />
require caution in their handling, use and storage.<br />
Low toxicity.<br />
• Schedule 6 (industrial poisons) – dangerous<br />
poisons available for agricultural and industrial<br />
application. Moderately toxic.<br />
• Schedule 7 (special poisons) – substances of<br />
exceptional danger that require special precautions<br />
in their manufacture and use. Extremely toxic.<br />
A comprehensive chart, detailing schedules for a wide<br />
range of herbicides and protective precautions that<br />
should be taken is available from the Kondinin Group<br />
(Ph: 9478 3343; web site www.kondinin.com.au).
Box 8.1 Personal safety and herbicide use<br />
Regardless of the poisons schedule of the herbicide or<br />
the protective equipment being used, two items should<br />
be immediately on hand for emergencies when using<br />
herbicides: Eye wash and several litres of clean water.<br />
Training<br />
It is not the purpose of this manual to provide<br />
guidelines on the storage, transport, mixing and use of<br />
herbicides. Any person using herbicides in bushland<br />
should have undertaken appropriate training. Training<br />
should cover the safe handling and use of herbicides<br />
and the use and calibration of equipment.<br />
• ChemCert WA runs a basic one day course on the<br />
safe use and handling of farm chemicals, including<br />
herbicides. Ph: 08 9341 5325<br />
• The ‘Certificate of Pest Control (commercial)<br />
Studying Pesticide Safety’ is a more detailed<br />
course offered by correspondence through<br />
Challenger TAFE’s WA Horticulture and<br />
<strong>Environmental</strong> Skills Centre.<br />
Ph: 08 9229 9513<br />
• ‘Pest Control Stage 1 Pesticide Safety’ is a one<br />
week pesticide safety course available through the<br />
Australian Centre for Work Safety, Carlisle TAFE.<br />
Phone: 08 9267 7353<br />
The last two courses fulfil the requirements to obtain a<br />
provisional pesticides applicators licence from the<br />
Pesticide Safety Section, Health Department of WA.<br />
Chapter 8 Herbicide Use in <strong>Bushland</strong><br />
The long-term effects of a number of herbicides are unknown. Herbicides can be absorbed through the skin, by<br />
inhalation or swallowing. Personal protective equipment (PPE) can limit exposure through these routes. The<br />
minimum PPE that should be worn depends on the toxicity and concentration of the herbicide and the<br />
conditions in which it is used. Maintaining a hygiene level that avoids as much contamination as possible is<br />
sensible.<br />
Clothing When handling concentrated chemicals during mixing, a PVC apron that reaches from shoulders to<br />
boots should be worn so that any spills can be quickly cleaned off. Always wear a long-sleeved shirt and long<br />
pants. Cotton, leather, canvas and other absorbent materials are not resistant to herbicides (even granular<br />
formulations) so the more layers of fabric the better. Wash work clothes separately from other laundry and airdry<br />
outside. Wash hands after handling contaminated clothes.<br />
Gloves Hands and forearms get the most exposure during spraying. Wear chemical-resistant gloves reaching<br />
up to the elbow and have sleeves tucked in. Butyl, nitrile or PVC gloves can be used. Make sure your gloves are<br />
clean and in good condition and replace them regularly. Always wash gloves before removing them.<br />
Boots Wear chemical-resistant rubber boots that reach at least halfway to the knee. Try to avoid walking<br />
through sprayed areas. If possible wash footwear before removing.<br />
Respiratory protection Dust/mist masks must fit and be used properly to be effective. Their use is most<br />
important in enclosed spaces or where the applicator is exposed to the chemical for long periods of time.<br />
Pesticides that can volatilise require the use of respirators. Check the label.<br />
Eye protection Safety glasses and goggles should be worn, especially during mixing when concentrated<br />
herbicide is being handled. A full face shield will give the best protection.<br />
Hygiene Be extremely careful during mixing. Exposure of the skin to concentrated herbicide during this short<br />
time can be the same as exposure from a full day working in the field. Wash hands before eating, drinking or<br />
smoking. Change clothing after spraying and wash hands, forearms and face with warm water and mild<br />
detergent. Shower at the end of the workday and wash your hair.<br />
Applicators should also obtain a good working<br />
knowledge of the herbicides they use, who else uses<br />
them in their work area, and how the herbicides<br />
behave and move in the environment. Material Safety<br />
Data Sheets are available from the herbicide<br />
manufacturers and distributors and provide<br />
information on mode of action, toxicology of the<br />
chemical and its fate in the environment. Other<br />
sources of useful information include:<br />
• Australian Weed Management Systems (Sindel<br />
2000) which has two chapters that provide a good,<br />
if sometimes technical, overview of these topics.<br />
Chapter 11. Herbicide mode of action and<br />
herbicide resistance (Preston 2000).<br />
Chapter 12. Application and fate of herbicides<br />
in the environment (Kent and Preston 2000).<br />
• Weed Control Methods Handbook (Tu et al. 2001).<br />
Chapters 5 to 7 provide information on safe use,<br />
mode of action and detailed information on the<br />
properties of several herbicides used in bushland.<br />
• The Extension Toxicology <strong>Network</strong> provides<br />
unbiased, easy to understand information on a<br />
range of herbicide-related subjects from entry and<br />
fate of chemicals in humans to movement of<br />
pesticides in the environment. Their ‘Toxicology<br />
Information Briefs’ are available online at<br />
http://ace.orst.edu/info/extoxnet/tibs/ghindex.html<br />
95
96<br />
Chapter 8 Herbicide Use in <strong>Bushland</strong><br />
Legislation<br />
In Western Australia, state and local government<br />
workers, consultants, contractors and volunteers who<br />
use herbicides are all bound by legislation governing<br />
pesticide use (The Health (Pesticides) Regulations 1956).<br />
These regulations are in place to protect the applicator,<br />
public and environment from the misuse of herbicide.<br />
Herbicide labels: The first point of reference and<br />
most easily obtained legal document is the herbicide<br />
label. The user has a legal obligation to read and follow<br />
the instructions on the label. Directions of use,<br />
protection of environment, storage and disposal and<br />
personal protective equipment must be adhered to.<br />
This includes using herbicides only for the weeds,<br />
situations and states or territories permitted on the<br />
label. Herbicide treatments of many bushland weeds<br />
are not listed for use on the labels. In Western<br />
Australia the only herbicide registered specifically for<br />
use in bushland situations is Fusilade 212 ® on Perennial<br />
Veldgrass (Ehrharta calycina). For this reason it may be<br />
necessary to apply for an off-label permit.<br />
Off-label permits: An off-label permit allows<br />
‘registered products to be used for a purpose or in a<br />
manner that is not included on the approved label’.<br />
Permits for off-label use of a registered herbicide can<br />
be obtained from the National Registration Authority<br />
(NRA). The Western Australian Department of<br />
Agriculture obtained a minor use off-label permit for a<br />
number of herbicides to be used specifically on<br />
environmental weeds in bushland. The permit (No.<br />
PER4984) is valid from 13 September 2001 to 30<br />
September 2006 unless cancelled and is available<br />
online at http://permits.nra.gov.au/PER4984.PDF. Any<br />
person wishing to use a herbicide product and<br />
application method in a manner outlined on the permit<br />
must read the permit.<br />
Licencing: Anyone applying herbicide for financial<br />
gain is required, by law, to be licenced with the<br />
Pesticide Safety Section, Health Department of Western<br />
Australia, and work for a registered company. This<br />
includes herbicide contractors and any bush<br />
regenerator who hires themselves out to community<br />
groups or government departments. Registration<br />
ensures that these people have undertaken<br />
appropriate training in the storage, preparation and<br />
use of herbicides. Contractors must also clearly<br />
display signs warning the public that herbicide is being<br />
used in the area.<br />
Water catchments: According to the Health<br />
Department, six herbicides may be used in Water<br />
Catchment Areas (WCA) as defined by the Water<br />
Corporation of Western Australia. These are 2,4-D,<br />
amitrole, glyphosate, hexazinone, picloram and<br />
triclopyr. They may only be used when no other means<br />
is suitable for eradication of a weed and several<br />
restrictions apply. These include:<br />
• Application is limited to injection or spot spraying<br />
with a large droplet spray.<br />
• Herbicides cannot be mixed within 50 metres of<br />
reservoirs, rivers or streams.<br />
• No application is to be made within 20 metres of<br />
reservoirs, rivers or streams except during<br />
summer months where these are dry.<br />
The full details and definition of WCA are available in<br />
‘Circular PSC88 Use of Herbicides in Water Catchments’<br />
This document is available online at http://www.public.<br />
health.wa.gov.au/environ/applied/PSC88.DOC). The<br />
circular is dated 1993, and is currently undergoing<br />
revision by the relevant government departments.<br />
In 1995, the Western Australian Department of<br />
<strong>Environmental</strong> Protection released a report on the<br />
acute toxicity of Roundup 360 ® to selected frog<br />
species (Bidwell and Gorrie 1995). Following the<br />
subsequent review of glyphosate use by the NRA,<br />
Monsanto introduced Roundup Biactive. This<br />
herbicide is registered for use in aquatic situations<br />
under certain conditions in all states of Australia. The<br />
minor use off-label permit PER4984 also allows the<br />
use of glyphosate in aquatic situations in accordance<br />
with label instructions.<br />
<strong>Bushland</strong> care<br />
Before applying herbicides it is essential to familiarise<br />
yourself with the site conditions. Compile a list<br />
including soil type, soil pH, proximity to open water,<br />
depth to groundwater, potential for run-off, occurrence<br />
of rare species (flora and fauna) etc. Base the decision<br />
to use herbicides on conservation targets for the site,<br />
potential behaviour of herbicides at the site in<br />
question, and the health and safety of applicators and<br />
others in the vicinity. Herbicides are poisons and<br />
should be used with caution.<br />
Minimising damage<br />
Following the label instructions does not mean offtarget<br />
damage will not occur. The degree of off-target<br />
damage depends on the herbicide used, soil type and<br />
landform, weather, application method and skill of the<br />
operator. Several steps can be taken to minimise the<br />
risks of herbicide damage to the environment:<br />
• Ask yourself if spraying is necessary (record<br />
reasons for choosing herbicide).<br />
• A protocol for storing, mixing, transporting,<br />
handling spills and disposing of unused herbicides<br />
and containers should be in place before<br />
purchasing herbicides.<br />
• Ensure that the person applying herbicide is<br />
trained in the safe storage, handling, preparation<br />
and use of the herbicide in question.<br />
• The person applying herbicide should have a good<br />
understanding of the issues surrounding weed<br />
control in native bushland (the possibility of rare<br />
and endangered species, the effects of trampling,<br />
damage caused by over-spraying, importance of<br />
correct identification of target weed).<br />
• Select a method that minimises off-target damage.<br />
Targeted techniques such as injection or wiping<br />
are most appropriate. If spraying is unavoidable<br />
use a large droplet spray to minimise drift. Use of<br />
in-line pressure regulators before the spray nozzle<br />
will help minimise droplet drift. Large-leafed plants<br />
like Arum Lily (Zantedeschia aethiopica) can have<br />
herbicide applied to individual leaves using a<br />
small, hand held, one litre garden sprayer. Hoods<br />
that direct herbicide onto the target plant are also<br />
available.
Chapter 8 Herbicide Use in <strong>Bushland</strong><br />
• Select herbicide and rate most effective at<br />
controlling the weed and with least damage to<br />
environment (selective, non-residual, low toxicity to<br />
humans and other organisms, lowest effective rate).<br />
Residual herbicides (metsulfuron methyl, picloram)<br />
can remain active in the soil for up two years,<br />
which can affect the growth of susceptible native<br />
plants over the period. Soil-mobile residuals could<br />
also contaminate waterways. However, for some<br />
weeds it may be more sensible to use a higher rate<br />
and/or a more toxic or more residual herbicide than<br />
an ineffective treatment that requires repeated<br />
application and does not remove the weed threat.<br />
• Understand the hydrology of the system that is<br />
being treated. The likelihood of run-off into<br />
waterbodies and/or leaching into the water table<br />
must be assessed. If necessary, establish ‘no<br />
spray’ zones. Only use herbicides that have been<br />
specially formulated to have minimal impact on<br />
aquatic organisms. Don’t add surfactants or<br />
wetting agents to such formulations as these are<br />
often more toxic to many aquatic organisms than<br />
the active ingredient in the herbicide. Use<br />
herbicides with low soil mobility where possible.<br />
• Establish a mixing area (easy access, no desirable<br />
species, not subject to erosion or run-off, rarely<br />
visited by public or workers).<br />
• Use a dye to minimise missed areas and avoid<br />
over-spraying.<br />
• Always apply at the most appropriate time<br />
(ineffective application results in failure and<br />
unnecessary use of herbicide in bushland).<br />
• Monitor effects of treatment on the whole plant<br />
community using a transect or quadrat-based<br />
approach which quantifies the number and cover<br />
of native plants. Native plant species include more<br />
than just trees and shrubs. Monitoring must<br />
include annual and perennial herbs, geophytes and<br />
grasses whose loss from the plant community<br />
should not be overlooked.<br />
• Identify mistakes and if necessary improve your<br />
method. Monitor the effects of treatment on the<br />
weed quantitatively. Use the same transects or<br />
quadrats set up for monitoring the plant<br />
community. At the very least, keep a record of<br />
plants/area treated, the herbicides and rate used,<br />
date and conditions.<br />
• Always follow up weed control work. If treatments<br />
are not followed up with further spraying or handweeding<br />
of overlooked or surviving plants, the<br />
initial treatment becomes a waste of resources and<br />
a pointless introduction of herbicide into the<br />
environment.<br />
Using contractors<br />
There is some concern about contractors entering the<br />
field with insufficient training in the application of<br />
herbicides within bushland situations. Contractors<br />
unsympathetic to bushland conservation are more likely<br />
to damage native plants through trampling,<br />
misidentification, or over-spraying. The contractor you<br />
select should have knowledge of the flora and an interest<br />
in bushland flora and fauna as well as an understanding<br />
of the chemicals used, the way they work and the weeds<br />
they control. They should be willing to use backpacks,<br />
hand held sprayers, or wiping devices when required.<br />
Such contractors are rare and in high demand<br />
throughout the peak weed season. At present, there are<br />
few suitable contractors available. The Australian<br />
Association of Bush Regenerators (Western Australia)<br />
(AABR (WA) Inc) has a list of those contractors in the<br />
Perth area that have sufficient experience to undertake<br />
bushland work. This list is available from AABR (WA)<br />
Inc., PO Box 1498, Subiaco, 6904. Ask around, get second<br />
opinions and if you are not happy with someone’s work<br />
be sure to let them know why!<br />
Make sure the spray contractor you hire and their<br />
employees have the appropriate training. Spray<br />
contractors must work for a business registered with<br />
the Pesticide Safety Section (PSS) of the Health<br />
Department of Western Australia (Ph: 08 9383 4244).<br />
A person with a provisional licence can carry out<br />
spraying as long as a person holding a full licence<br />
supervises them. Any person operating a pesticide<br />
spraying company must hold a full licence.<br />
To get the most for your money and the best job<br />
done, it is important to have weed maps and a<br />
contract. The contract (Appendix 1) outlines the work<br />
to be done and ensures that if the job is not done<br />
satisfactorily you are in possession of a written<br />
agreement. The Weed maps are multi-purpose, they<br />
allow you to show the contractor the location of the<br />
weed populations; walk around the bushland with the<br />
contractor and relate populations to those on the<br />
map. By supplying the contractor with the weed map<br />
before the job, they are more easily able to relocate<br />
each population. The map also provides a monitoring<br />
tool that allows you to assess the reduction in<br />
population area and ensure no populations are<br />
overlooked by the contractor. In combination these<br />
two documents are invaluable (Box 8.2).<br />
Some herbicides used in bushland<br />
All applications and concentrations quoted in this<br />
manual are intended as an illustrative guide. They are<br />
covered by minor use off-label permit number<br />
PER4984, which is only valid for Western Australia.<br />
Some useful herbicide terminology:<br />
• Contact – kills only plant tissue to which it has<br />
been applied. Old or well-established annual plants<br />
may grow back after such treatments.<br />
• Systemic herbicide – penetrates plant cells and<br />
moves through the plant from shoots to roots in<br />
the phloem.<br />
• Broad spectrum – kills a wide range of plants.<br />
• Selective – kills only a particular type of plant, e.g.<br />
grasses.<br />
• Non-residual (knockdown) – kills existing plants<br />
but has no effect on subsequent germinants.<br />
• Residual – remains active in soil for some time<br />
(may kill germinating seeds (pre-emergent) and<br />
susceptible plants).<br />
• Post-emergent – applied directly to established<br />
plants and/or soil.<br />
• Pre-emergent – applied to the soil before the weed<br />
germinates, killing germinating seedlings (preemergent<br />
herbicides will also kill susceptible<br />
native seedlings).<br />
97
98<br />
Chapter 8 Herbicide Use in <strong>Bushland</strong><br />
Box 8.2 Using contractors to spray African Lovegrass at Talbot Road <strong>Bushland</strong><br />
Between 1999 and 2001 infestations of African Lovegrass (Eragrostis curvula) at Talbot Road were mapped<br />
annually as part of the overall weed management strategy. The weed was found to be widespread on the<br />
tracks and bushland edges. In August 1999 contractors were employed to spot spray the infestations with a<br />
1 % solution of glyphosate. The work was carried out when the African Lovegrass was actively growing and<br />
cost $1645.<br />
A thorough examination of the site after spraying revealed that several populations of African Lovegrass had<br />
missed treatment altogether. In a number of other areas Perennial Veldgrass (Ehrharta calycina) had been<br />
mistaken for African Lovegrass. While glyphosate was appropriate to use on dense infestations of African<br />
Lovegrass growing along path edges, Perennial Veldgrass extended into the bushland and grew closely among<br />
native plants. Where Perennial Veldgrass clumps had been sprayed, off-target damage from the glyphosate was<br />
evident. If Perennial Veldgrass had been the target weed at this site a grass-selective herbicide would have<br />
been specified.<br />
Although the contractors had originally been met on site and the job discussed in detail, no maps were<br />
supplied to them and no contract outlining the work had been signed. If a contract had been signed, both<br />
parties would have had a clear understanding of exactly what was required and a means of redress when those<br />
requirements were not met.<br />
After discussions, the contractors returned to respray missed infestations. When the contractors were reemployed<br />
to follow up the work in 2000, maps of African Lovegrass distribution were supplied and a written<br />
contract signed before the work began. This time we had comeback if necessary. It was not; the contractor did<br />
a thorough, professional job.<br />
The treatment was repeated in 2001 following a summer fire that burnt through most of Talbot Road <strong>Bushland</strong><br />
in 2001. The maps were particularly useful for locating populations of resprouting African Lovegrass plants for<br />
treatment following the fire. The follow-up work in 2000 and 2001 cost $960 and $880 respectively. Maps show<br />
that the populations have decreased substantially over this time.<br />
1999 2001<br />
Distribution of African Lovegrass • at Talbot Road <strong>Bushland</strong> prior to treatment in 1999 and after treatment in 2001.
Notes References<br />
Bio<br />
accumulation<br />
Average half-life<br />
in water<br />
Absorbed by Mode of action Average soil half-life Mobility in<br />
soil<br />
Basic properties Target weed<br />
species<br />
Poison<br />
schedule<br />
312, 305,<br />
119, 35,<br />
349, 226,<br />
247<br />
Toxic to most grasses except Vulpia<br />
spp and Poa annua . Toxic to fish.<br />
15 days low stable high potential<br />
in aquatic<br />
organisms<br />
foliage Inhibits acetyl-CoA<br />
carboxylase preventing the<br />
synthesis of lipids required<br />
for growth and maintenance<br />
of cell membranes.<br />
annual<br />
and perennial<br />
grasses<br />
S6 systemic,<br />
selective,<br />
non-residual,<br />
post- emergent<br />
Fluazifop-p-butyl<br />
(Fusilade 212 ® )<br />
Moderately toxic to aquatic species. 119, 61,<br />
247<br />
1 hour to 40 days<br />
(dependent on<br />
product)<br />
5-25 days lowmoderate<br />
Inhibits acetyl-CoA<br />
carboxylase preventing the<br />
synthesis of lipids required<br />
for growth and maintenance<br />
of cell membranes.<br />
foliage and<br />
roots<br />
some annual<br />
and perennial<br />
grasses<br />
Sethoxydim (Sertin Plus ® ) S5 systemic,<br />
selective,<br />
post- emergent,<br />
non-residual.<br />
Chapter 8 Herbicide Use in <strong>Bushland</strong><br />
Table 1. Properties of some herbicides used on bushland weeds.<br />
312, 204,<br />
119, 219,<br />
220<br />
47 days low 12 days to 10 weeks none known Little to no soil activity. In wetlands<br />
use special aquatic formulations.<br />
foliage Inhibits the shikimic acid<br />
pathway depleting aromatic<br />
amino acids required for<br />
protein construction.<br />
annual<br />
and perennial<br />
weeds<br />
S5 systemic,<br />
broad spectrum,<br />
non-residual,<br />
post- emergent<br />
Glyphosate (RoundUp ® ,<br />
RoundUp BiActive ® ,<br />
Glyphosate 360 ® & others)<br />
312, 106,<br />
119, 247<br />
<strong>Environmental</strong> persistence (up to 2<br />
years). Poses risk of groundwater<br />
contamination. Most grasses are<br />
resistant. Slight to moderate toxicity<br />
to fish and aquatic organisms.<br />
slight in fish,<br />
none recorded in<br />
milk or tissue of<br />
mammals<br />
1-40 days<br />
(depending on<br />
sunlight<br />
intensity)<br />
moderatehigh<br />
20 - 300 days<br />
(average 90 days)<br />
Auxin mimic - causes<br />
uncontrolled, disorganised<br />
growth.<br />
foliage and<br />
root uptake<br />
annual and<br />
perennial<br />
broadleaf<br />
weeds, vines,<br />
and woody<br />
plants<br />
S6 systemic,<br />
selective,<br />
residual<br />
Picloram + Triclopyr<br />
(Grazon DS ® or Access ® )<br />
119, 247,<br />
104<br />
little to none Commonly used herbicide. Low to<br />
non-toxic to birds, fish and bees.<br />
NOTE: The ester formulation is<br />
highly toxic to aquatic organisms.<br />
3 hours<br />
to 4 days<br />
moderatehigh<br />
30 - 90 days<br />
(average 46 days<br />
longer in cold or arid<br />
conditions)<br />
Auxin mimic - causes<br />
uncontrolled, disorganised<br />
growth.<br />
roots and<br />
foliage<br />
annual and<br />
perennial<br />
broadleaf<br />
weeds, vines,<br />
and woody<br />
plants<br />
Triclopyr (Garlon 600 ® ) S6 systemic,<br />
selective,<br />
non-residual,<br />
post-emergent<br />
110, 119,<br />
226<br />
21-30 days none known Biologically active at low rates.<br />
Persistence in soil varies according<br />
to soil pH, rainfall and soil type.<br />
Moderate to low toxicity to fish<br />
moderate -<br />
high (more<br />
mobile in<br />
alkaline<br />
conditions)<br />
14 - 180 days<br />
(average 60 days -<br />
more persistent in<br />
alkaline soils)<br />
Inhibits acetolactate<br />
synthase preventing cell<br />
division and thus growth.<br />
foliage and<br />
roots<br />
bulbs and<br />
broadleaf<br />
weeds<br />
unscheduled systemic,<br />
residual,<br />
post-emergent<br />
Metsulfuron methyl<br />
(Brush-off ® , Ally ® )<br />
111, 222,<br />
35<br />
Persistence varies according to<br />
soil pH, rainfall and soil type. Low<br />
toxicity to birds, mammals, fish and<br />
aquatic invertebrates.<br />
7-14 days does not<br />
accumulate in<br />
the milk or<br />
tissue of<br />
animals<br />
moderatehigh<br />
14 - 60 days<br />
(9 months in<br />
alkaline soils)<br />
Inhibits acetolactate<br />
synthase preventing cell<br />
division and thus growth.<br />
foliage and<br />
roots<br />
bulbs and<br />
broadleaf<br />
weeds<br />
Chlorsulfuron (Glean ® ) S5 systemic,<br />
residual,<br />
post-emergent<br />
105,169,<br />
312, 61<br />
8-40 days none known Low toxicity to mammals, birds,<br />
fish, aquatic invertebrates and bees.<br />
Soluble in water - potential for<br />
contamination.<br />
high<br />
potential<br />
12 days to 1 year<br />
(highest under<br />
anaerobic conditions and<br />
low microbial activity)<br />
Auxin mimic - causes<br />
uncontrolled, disorganised<br />
growth.<br />
foliage and<br />
some root<br />
absorption<br />
broadleaf<br />
weeds<br />
Clopyralid (Lontrel ® ) S5 systemic,<br />
selective,<br />
residual,<br />
post-emergent<br />
61, 119<br />
Low toxicity to birds, mammals,<br />
fish and molluscs. Moderate to high<br />
toxicity to shrimp and aquatic<br />
insects.<br />
does not<br />
accumulate in<br />
tissues (
100<br />
Final Note<br />
In the end, environmental weed management is about<br />
protection of our unique bushlands through carefully<br />
targeted and effective on-ground actions – on-ground<br />
actions that prevent introduction or spread of<br />
environmental weeds, and work towards their control and<br />
sometimes their eradication while protecting complex<br />
natural systems. The case studies outlined in the various<br />
chapters highlight the importance of having clear goals<br />
based on an understanding of the conservation values of a<br />
particular site, a thorough knowledge of the weed/s being<br />
targeted and a well-defined strategy. Sometimes it takes a<br />
series of trials and a number of years to formulate such<br />
strategies. To gain an understanding of the effectiveness of<br />
those strategies monitoring needs to be in place and<br />
results should guide management actions. This kind of<br />
framework, together with the resources to support it, is<br />
central to effective environmental weed management.<br />
Access to technical resources stands out as particularly<br />
important. This seems especially true for weed<br />
management in the bushlands of south west Western<br />
Australia as they support such an incredibly diverse flora.<br />
Effective management is often about knowing and<br />
understanding very complex systems. In addition though,<br />
technical support is also important for setting up trials<br />
and putting in place monitoring. One of the most valuable<br />
undertakings of this project has been the work carried out<br />
in conjunction with the various land managers setting up<br />
replicated trials to test various control options for serious<br />
weeds, and the impacts of those control options on native<br />
plant communities. This approach provided solid data to<br />
guide management actions, and also provided<br />
demonstrable outcomes to potential funding sources. At<br />
the same time, community volunteers involved gained an<br />
understanding of the options available, including the<br />
practicalities, costs and impacts of various physical and<br />
chemical control methods. They were then able to make<br />
informed decisions about implementation of those control<br />
options across particular bushland sites.<br />
Typical examples include the trials on management of<br />
Yellow Soldier (Lachenalia reflexa) in Shenton <strong>Bushland</strong>,<br />
on control of Harlequin Flower, (Sparaxis bulbifera) and<br />
Tribolium (Tribolium uniolae) invading the Brixton Street<br />
Wetlands and the work on Taro (Colocasia esculenta) along<br />
the Gingin Brook. The work on Holly-leafed Senecio<br />
(Senecio glastifolius) by the Western Australian<br />
Department of Agriculture in Albany provided similar<br />
outcomes. In all of these examples the results of the trial<br />
work provided solid information on which to base<br />
management strategies. Importantly the information<br />
gathered was also often instrumental in acquiring funding<br />
to begin implementation of those strategies across<br />
particular bushland sites. Continued funding over time<br />
was then often facilitated by the collection of monitoring<br />
data. Those data often demonstrated effectiveness of the<br />
strategies, regeneration of native plant communities<br />
and/or provided justification for funding priorities. There<br />
are a number examples throughout the text. Typical is the<br />
series of maps illustrating the reduction of Perennial<br />
Veldgrass (Ehrharta calycina) cover in Shenton <strong>Bushland</strong><br />
over four years, and the subsequent allocation of<br />
resources over that time.<br />
Characteristically, most funding for on-ground works over<br />
the life of this project has been in the form of short-term<br />
grants, generally applied for by community volunteers,<br />
although sometimes in conjunction with local or state<br />
government bodies. Often the funding is only available for<br />
12 months and must be re-applied for each year until the<br />
work is complete. Such a system has fairly obvious<br />
shortcomings. Changes in management personnel, or in the<br />
structure of volunteer groups, usually sees a year of<br />
funding missed. A season of follow-up control/management<br />
work is then missed and the efforts of previous years are<br />
wasted. In addition there is little flexibility in the resources<br />
that are available. For example, under such funding<br />
arangements it can be impossible to find money for weed<br />
management following unplanned fire and so an excellent<br />
window of opportunity is often missed.<br />
Clearly successful weed management in natural areas is<br />
dependent on a consistent effort over many years and<br />
access to long-term, secure funding. Certainly, one of the<br />
most encouraging trends, over the life of this project, has<br />
been witnessing both state and local government commit<br />
funding to weed management work originally initiated by<br />
the community, through short-term grants. Government<br />
bodies seem to be able to do this once it becomes<br />
apparent that work is taking place within a clearly<br />
defined strategy, that accurate costing is possible and<br />
there are demonstrable outcomes. Funding for the work<br />
on Harlequin Flower and Tribolium at Brixton St,<br />
Perennial Veldgrass, Yellow Soldier and Freesia control at<br />
Shenton <strong>Bushland</strong> and management of the serious weed<br />
at Talbot Rd, all initially came about through community<br />
efforts but have subsequently been picked up by state or<br />
local government, often becoming a part of their<br />
recurrent budget. Fundamental to securing this funding<br />
has been the availability of on-ground technical support<br />
to map the weeds, set up trials and conduct monitoring.<br />
The EWAN project officers have provided much of that<br />
technical support.<br />
Part of the intention of writing this manual was to highlight<br />
the need for state and local government authorities to<br />
allocate more resources for technically skilled people,<br />
working on the ground, so that environmental weed<br />
management can start to be undertaken within this sort of<br />
framework. The intention was also to highlight the need to<br />
provide technical support for Friends groups and<br />
community volunteers who carry out much of the bush<br />
regeneration and environmental weed management in<br />
south west Western Australia at present. The examples<br />
provided through the text illustrate what can be achieved<br />
when such support is available.<br />
These examples have mostly focused on protection of<br />
particular bushland patches. Although all are drawn from<br />
south west Western Australia they have relevance for land<br />
managers in other parts of the country. They demonstrate<br />
the importance of knowing and understanding particular<br />
sites and mostly they illustrate that if we really try, often<br />
we can control and manage environmental weeds where<br />
they are threatening what remains of our bushlands.<br />
Significantly, for most of the case studies described,<br />
successful outcomes have been reliant on a combination of<br />
community and local, state and federal government efforts.<br />
Walking through Shenton <strong>Bushland</strong> in spring 2002, much of<br />
the Perennial Veldgrass and large populations of Freesia<br />
have disappeared. In their place carpets of a native daisy,<br />
Slender Podolepis. At Brixton St the Harlequin Flower<br />
program is down to hand-weeding remaining isolated<br />
populations leaving room for the native herbs to<br />
recolonise, and along the Gingin Brook, where the Friends<br />
have been working, Taro has been replaced by dense<br />
stands of the native Tassel Sedge and seedlings of<br />
Paperbarks and Flooded Gum.
Appendix 1 Herbicide Spraying Contract<br />
1 General<br />
The Contractor shall allow for the supply of all labour, plant and equipment, materials, chemicals and wetting agents required to gain<br />
effective control of ________________________________ (weed) in ________________________________ (site).<br />
2 Distribution<br />
2.1 All spraying shall be carried out within the bushland of ______________________ (site) in the area on the attached map.<br />
Amendments may be made on the agreement of both parties (Friends group/Council and Contractor).<br />
2.2 Herbicide shall be spot sprayed on __________________(weed) only. The Contractor shall be responsible for the cost of<br />
purchase of materials and respraying areas of unsatisfactory control, at the appropriate time when suitable conditions prevail.<br />
2.3 The Contractor shall achieve greater than 90 % mortality for ________________ (weed) in sprayed areas. The herbicide<br />
manufacturer’s guarantee of weed kill shall in no way remove the Contractor of his obligation to respray, should the required<br />
mortality rate not be achieved.<br />
2.4 The Contractor shall include in all prices an allowance to achieve the mortality rates mentioned.<br />
2.5 An inspection will be made by __________________________________(Friends group/Council) after the initial spraying to<br />
determine effectiveness and so determine the area to be resprayed, if necessary.<br />
3 Mixing<br />
All herbicides are to be thoroughly mixed prior to application and agitated during spraying.<br />
4 Wetting Agent<br />
4.1 The Contractor shall apply a wetting agent in accordance with the herbicide manufacturer’s recommendation,<br />
e.g. Agral 600 3 mL/L.<br />
4.2 With the herbicide, the volume of water used should be sufficient to ensure an even application of herbicide.<br />
5 Marking Dye<br />
Marking dye shall be used at a rate that is sufficient to see areas sprayed 7 days after application.<br />
6 Spray Drift<br />
The pressure of application shall be kept to a level that prevents excessive spray drift.<br />
7 Plant and Equipment<br />
7.1 All equipment and vehicles must be washed down prior to entering _______________________________________(site).<br />
7.2 All tanks, spray lines to be washed out and thoroughly cleansed, and treated with a product such as Chem Clean before<br />
entering ______________________________________(site).<br />
8 Leaks<br />
All leaks (chemical and/or fuel or oils) shall be immediately reported to ___________________________________________<br />
(Friends group/Council), cleaned up in the appropriate manner and removed from the bushland immediately.<br />
9 Spray Equipment<br />
All plant and equipment used for the application of herbicides shall be suitable for this purpose and be in excellent working order.<br />
10 Control<br />
10.1 Control shall be at a time that _______________________________(weed) is actively growing as agreed to by both parties.<br />
10.2 A log of works shall be completed on a daily basis, showing the following details:<br />
Name of Company _________________________________________ Name of Operator____________________________________<br />
Location/area sprayed___________________________________________ Date ________________ Time________________<br />
Weather Conditions e.g.: Fine, showers etc _________________________________________________________________________<br />
Wind Direction_____________________________________________________ Wind Speed________________________<br />
Chemical Applied______________________________________ Full trade name______________________ Rate_________________<br />
11 Warning Signs<br />
It is the operator’s responsibility to warn any members of the public who venture into the bushland during the spraying to withdraw.<br />
12 Harmful Chemicals<br />
The Contractor shall not use a herbicide in any manner or circumstance that is dangerous, harmful or injurious to health (refer regulation<br />
20 (1) of the Health (Pesticides) Amendment Regulations 1986).<br />
13 Licence<br />
A copy of the Company’s ‘current’ Pesticides Operator’s Licences, stating chemicals that individual Operators are registered to<br />
apply, together with the names of Operators who will be applying herbicides under this Contract, must be submitted with signed<br />
specification. The contractor shall guarantee the competency of Operators applying herbicides under this Contract.<br />
14 Commencement and Completion<br />
The contractor shall notify ______________________________________________ (Friends group/Council) at least 24 hours prior to<br />
starting and on completion of work.<br />
I hereby agree to the above specification<br />
Signature Name of Company Date<br />
Please Print Name<br />
(Courtesy Bob Dixon, Botanic Gardens and Parks Authority)<br />
101
102<br />
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