Alternanthera sessilis (L.) R.Br. ex DC.

Code

ALRSE

Growth form

Broadleaf

Biological cycle

Annual to vivacious

Habitat

terrestrial

China: Alternanthera sessilis flowers and fruits from May to July.
Mayotte: Alternanthera sessilis flowers and fruits all year round.
Nicaragua: Alternanthera sessilis flowers and fruits all year round.
West Indies: Alternanthera sessilis flowers and fruits all year round.

Alternanthera sessilis is a herbaceous plant that can be annual or perennial depending on the humidity of the environment. In lowland conditions or in irrigated rice fields, it is most often a perennial. Dissemination by seed or vegetative propagation by cuttings of stem fragments. The fruits are myrmecophilous.

A. sessilis can be confused with A. philoxeroides, the latter species is distinguished by its inflorescences which is also a white globose spikelet, but is held by a 1-9 cm long peduncle.

Alternanthera sessilis prefers moist soils, along ditches, fallow land. The plant grows in moist soils of the lakes, swamps, irrigation canals and rice paddies dams and navigation channels, up to 1200 m altitude.

Central Africa: Alternanthera sessilis is a widely naturalized exotic species, cosmopolitan and very common, sometimes aquatic or palustrine (riverbanks, ponds, ditches, Echinochloa marshes), sometimes terrestrial on banks and sandy islets (exundated river islets) or anthropophilous: roadsides, villages, crops, rubble.
China: Alternanthera sessilis grows on roadsides, in gardens and swamps.
Comoros: This species occurs in ruderal areas, along roadsides, in settlements up to the forest of average altitude.
French Guiana: Species rather present in vegetable zone at the edge of the fields, it develops well in wetlands and in places rich in nitrogen. It is frequent in the ruderal vegetation of wetlands.
Madagascar: This species prefers hydromorphic and relatively rich moist alluvial soils in conditions more or less shaded, in all climatic zones of Madagascar: edges of canals, marshes and roads. It is also a weed of vegetable crops, taro and rice lowland and upland rice on moist soil, in semi-intensive culture system with organic manure.
Mauritius: It occupies very often, but not exclusively, humid sites, at the edge of streams, lakes and swamp especially under moist and wet areas.
Mayotte: Rather common species in the wetlands and on the hydromorphic grounds, especially in the back mangroves, but also in degraded environments.
Nicaragua: Alternanthera sessilis is a very common species, in disturbed sites, in all parts of the country; from 0 to 750 m altitude.
Thailand: Weed on marshy land, also along paths, around villages, etc.; up to 1000 m altitude or more.
West Indies: Alternanthera sessilis is a ruderal species that grows on moist soil, from 0 to 300 m (500m) altitude.

Global harmfulness

Sometimes noxious.

Local harmfulness

Burkina Faso: Alternanthera sessilis is frequent and scarce.
Comoros: A. sessilis is found in association with other weeds in crops, found moderately common in fallow fields and the old cultures of banana, cassava and vanilliers.
Côte d'Ivoire: frequent and scarce.
Ghana: rare and scarce.
French Guiana: A rarely problematic weed, it does however have vigorous taproots that can complicate manual weeding. It is locally abundant.
Madagascar: Weed common crops in low-lying areas but generally little abundant and associated with other species creeping or not. This rampant species can form a dense population difficult to remove if the weeding is too late. The very moist soil in which it grows makes it difficult to manage with small hand tools. A. sessilis can be troublesome in vegetable crops invading plots from poorly cleaned borders.
Mauritius: It can become a significant weed in some vegetable crops and rice paddies with a low average aggressive. On the contrary, it is quite rare in sugar cane where it is weakly aggressive.
Nigeria: rare and scarce.
Senegal: rare but abundant when it is present.
Chad: rare and scarce.
Tanzania: Frequent but not abundant.

Food: The young stems and leaves of Alternanthera sessilis are eaten as a green vegetable.
Medicinal: An infusion of the whole plant is used in Indonesia as a remedy against intestinal pain, diarrhea, dysentery, and externally to treat wounds or against inflammation and to decrease fever. A. sessilis is used in local medicine in Taiwan, often mixed with other medicinal plants, to treat hepatitis, chest angina, bronchitis, asthma and lung problems, to stop  bleeding and as capillary stimulating agent. It is also used locally in India against dysentery, as cholagogue, abortive and to treat snake bites, burns and boils and in Thailand and Sri Lanka, as galactogen. Traditional uses as anti-inflammatory and to treat wounds are proven by the anti-inflammatory and anti-hyperglycemic activities of the extracts of aerial parts of the plant. In Comoros it is used externally against skin diseases.

Global control

For advice on weed control of irrigated and lowland rice in Africa, visit :

For advice on weeding perennial broadleaf weed of irrigated and lowland rice in Africa, please visit

For advice on weeding perennial broadleaf weed of irrigated and lowland rice in Africa, please visit

Biological control: Zettler and Freeman (1972) in their discussion on the biocontrol of aquatic plants, state that in India, Alternanthera sessilis a near relative of alligator weed, is affected by the fungial species Corticium solani, Colletotrichum capsici, Glomerella cingulata, Phoma spp., and Albugo bliti.
Chemical: Amitrole is very effective. Reasonably effective are 2,4-D for broadleaved weeds (1-1.5 kg a.i./ha in 200 liters of water) and MCPA (0.5-1 kg a.i./ha in 200 liters of water), but repeated applications are necessary.

Local control

Comoros: Alternanthera sessilis is a weed easy to pull off, weeding is done manually.
Madagascar: Control can be achieved by good soil preparation and manual grubbing or manual tillage with angady for taro crops in the uplands of the Highlands. In cropping systems based on rainfed rice, vegetable crops and taro, the plots are generally very small and the very different crops are side by side making it difficult to use post-emergence herbicides such as 2 , 4-D.
Mauritius: It is effectively controlled by post-emergent herbicide mixtures recommended in sugar cane. It must be removed manually or by weeding in other crops.

Herbarium pictures ReCOLNAT: https://explore.recolnat.org/search/botanique/simplequery=Alternanthera%2520sessilis