Japanese gardens and plants – Japonica Plants Nursery

Plant profile: Anemonopsis macrophylla

Anemonopsis macrophylla, the false anemone, is a herbaceous perennial in the Ranunculaceae family. It’s also one of the most exquisite flowers you can grow in the shade. In late summer, the nodding lilac and white flowers float above the clump of jagged-edged foliage like miniature upturned lotuses sculpted out of wax.

It is this resemblance which gives the plant its Japanese name, rengeshoma, lotus-flowered Actaea (shoma is Actaea, and renge is lotus). If you add ‘ki’, gold, you get another gorgeous Japanese endemic, Kirengeshoma palmata.

Anemonopsis macrophylla is found in the wild only in a few places on Honshu, the main island of Japan. It grows in the woodlands of the central mountains, and in the garden likes similar sheltered conditions. It needs shade and a good humus rich soil, and will not tolerate drying out. It’s also a good idea to protect it from slugs. ‘Slug Gone’ wool pellets work well for me and are non-toxic as well as good for the soil. Some authors suggest that it benefits from a slightly raised planting position. Overall, unless you are blessed with the exact conditions it prefers, sadly rare in the U.K., it is a plant that definitely requires a little extra effort to grow well.

There is also a white form of Anemonopsis macrophylla, sometimes sold under the name ‘White Swan’, and a double form, ‘Flore plena’. Though lovely, sought-after, and according expensive, neither of these beat the elegance of the straight species, in my opinion. In Japan, there is also a form with variegated leaves and one with a dark petiole (‘Aojiku’, a very desirable feature in Japanese horticulture). I have had, as yet, no success with these from imported seed.

Plant profile: Maianthemum japonicum

Maianthemum is a genus of rhizomatous perennials, widely distributed across Asia, Europe, North and Central America. Maianthemum japonicum, formerly Smilacina japonica, is native to Japan, China, Korea and the far east of Russia. Its common name is Japanese False Solomon’s Seal, as the genus is closely related to Polygonatum.

Maianthemum japonicum has arching stems to about 12-18”, 30-45cm, with a panicle of many tiny starlike white flowers at the tip of the stem in May and June. These are followed by shiny red berries in autumn. It prefers woodland conditions: humus rich soil in partial shade, not too dry. In its native habitat it grows in slightly damp montane forests. Propagation is by division of the creeping rhizomes in spring.

As with many native Japanese plants, a number of variegated varieties have been selected over the years.

Maianthemum derives its name from the Greek for ‘May Flower’. The Japanese name, ユキザサ, literally ‘snow bamboo’ derives from the white flowers and leaves reminiscent of Sasa bamboo leaves. The new shoots are harvested and eaten as a wild vegetable in Japan, and when boiled are said to taste of adzuki beans, giving it the common name of ‘Red Bean Greens’.

*Maianthemum japonicum* ‘Ki Shiro Fukurin Fu’

Tortoiseshell and Crow Leaf: Japanese Variegation Patterns

The Japanese horticultural tradition is very different to ours here in the U.K. Whilst British nurseries and botanical gardens sent plant hunters around the world in search of novelties, Japanese horticulturists focused on collecting their own, astonishingly rich, native flora, and creating almost infinite varieties by selection and, to a lesser extent, by hybridization. (Read more about Koten Engei here.)

One of the most valued characteristics is variegation, of which, again, there are innumerable forms. Some of the many names for Japanese variegation patterns are listed below, ranging from the straightforwardly descriptive to the distinctly poetic.

Fuiri means ‘variegation’ and pattern names often end with -fu.

Shiro fu – white variegation
Aka fu – red variegation
Ou sai – yellow
Ogon – gold
Shima fu – striped variegation e.g. ki shima fu – yellow striped variegation
Chiri fu – mottled variegation
Sunago fu – scattered sand variegation
Hakikomi fu – brush strokes / swept variegation
Kikkou fu – tortoiseshell pattern
Naka fu – central variegation (i.e. in the centre of the leaf)
Sankou naka fu – multicoloured / complex central variegation
Fukurin fu – bordered variegation , e.g Shiro fukurin fu – white bordered variegation
Fuka fukurin fu – wide-margined variegation
Ito fukurin – thread border
Tora fu – tiger variegation

Some of the more poetic names:

Akebono – Dawn
Gin getsu – Silver moon – very little green on white leaves
Ama no gawa- Milky Way
Zansetsu – Lingering snow
Awa no Tsuki – Moon of Awa
Koutei – Yellow Emperor
Reihou – Sacred mountain
Dai kouga – Great yellow river
Byakko – White tiger – mainly white leaves with green tips
Muhyou – Hoarfrost
Gin sekai – Snow covered scene
Chouyou – Sunrise
Kinkaku – Golden pavilion
Shunrai – Spring thunder – fine white lines on green leaves
Nagori yuki – Remaining snow
Sajin – Dust
Haku un – White clouds – actually a creamy yellow variegation
Senkou – Flash
Hagoromo – angels’ raiment, robe of feathers
Yuki no shita – Under the snow
Karasu ha – Crow leaf – almost black leaves
Oboro zuki – Hazy moon
Kichou – Yellow butterfly
Nishiki – brocade – beautifully multicoloured or complex variegation
Raijin – Thunder god
Suikou – Green light
Ryoku un – Green clouds
Ginga – Galaxy

(Apologies for any errors – I speak very little Japanese at the moment and am therefore reliant on internet sources!)

Plant Profile: Asimitellaria

Asimitellaria is a recently recognised genus of plants in the Saxifrage family, previously included in the genus Mitella, and related to Tiarella, Heuchera, and Tellima (which is an anagram of Mitella). There are 11 species, 10 endemic to Japan and one to Taiwan. Asimitellaria are woodland plants, preferring a humus rich soil, not too dry, in partial to full shade. They are mostly small, evergreen, clump-forming or gently creeping perennials, grown for their attractive lobed foliage, which is sometimes patterned in reds and purples. The spikes of tiny cap shaped flowers in spring give the plant its common name of Mitrewort or Bishop’s Cap. They usually produce plentiful seed which germinates readily when fresh and kept moist.

Asimitellaria makinoi is a diminutive species – only around 10cm tall- from Japan, introduced by Crûg Farm. The leaves are delightfully patterned in purple with silvery patches, and the flowers and flowering spikes are red.

Asimitellaria acerina is rather larger, growing up to 40 cm in height, with leaves up to 10 cm. The glossy green palmate leaves give it its Japanese name of Maple-leaved Mitella. The delicate spikes of little flowers are greenish-pink.

Asimitellaria kiusiana is another low-growing plant, to only 20 cm or so. The green leaves have variable red patterning along the veins, and the flower spikes are pale green.

Plant Profile: Deinanthe

Deinanthe is a small genus, of only two species, closely related to hydrangeas and rarely grown in U.K. gardens. Commonly known as false Hydrangeas, the botanical name comes from the Greek Deinos meaning extraordinary, and anthos meaning flower. They are herbaceous perennials, very hardy, slowly forming a clump about 15-18″, 40-50cm tall and wide. They are woodland plants and need partial to full shade and a humus rich soil. Summer moisture is essential – they will not tolerate drying out. Watering should be reduced as the growing season comes to an end.

Deinanthe bifida is a Japanese endemic, introduced to the West by the Russian botanist C. J. Maximowicz in 1860. The flowers are white. A few varieties are available, such as ‘Pink Shi’ and ‘Pink-Kii’, which have pink buds opening to slightly pink-tinged flowers, and may occasionally produce a few sterile florets. It is slightly larger and easier to grow than Deinanthe caerulea. The hydrangea-like leaves are split at the end rather attractively.

Deinanthe caerulea is a Chinese species, native to Hubei, introduced by E.H. Wilson in about 1911. Smaller and slower-growing than D. bifida, it is even less tolerant of summer drought. The flowers are a remarkable waxy purplish blue. It is sometimes sold under the trade name ‘Blue Wonder’. There is also a hybrid between the two species, sometimes known incorrectly as D. caerulea European Form, which has pale blue flowers.

Propagation is by seed, when produced, or more reliably by division in spring.

How to grow Japanese Maples

One of the most evocative of Japanese plants, Acer palmatum cultivars are easy to grow as long as they are sited correctly. Whether in the ground or in containers they need shelter from cold or drying winds. Cool dappled shade is the ideal position. Green cultivars, and some purples, tolerate sun best. Red leaved cultivars need some sun, or the colour will not develop properly, but don’t like full sun all day. Variegated or more delicate dissectum and linearilobum cultivars will need shade at least during the hottest part of the day to prevent scorching and some, like ‘Ukigumo’, can only be grown successfully in shade.

They do best in a moist but well-drained soil with plenty of organic matter, ideally slightly acidic. In a container, the standard advice is to use John Innes 2 or 3, mixed with an ericaceous compost, but it is better for the environment to use a good quality peat free ericaceous, such as those available from Sylvagrow or Dalefoot. Top pots with gravel to suppress weeds, or mulch well with compost or leafmould in the ground, but make sure the mulch doesn’t touch the trunk. Feed with a balanced fertiliser in spring before the leaves emerge.

*Acer palmatum* ‘Omureyama’ starting to colour in autumn

Correct watering is important. They need a good supply of moisture, and won’t tolerate either drought or water-logging well. They are quite shallow rooted, so make sure they are not crowded by other plants competing with them. Besides, they are best given space to show off their beautiful form.

Emerging foliage of Acer palmatum ‘Katsura’

Acers are perfectly hardy, but in pots their roots are more vulnerable to frost, so in colder area the pots should be wrapped in fleece or moved to a protected spot in winter. Acers come into leaf very early in the year and the new foliage can be caught by late frosts. This won’t kill them but will set them back, so protect with fleece when frosts are expected.

Acers don’t need much pruning – simply removed dead, damaged or diseased branches, and any that are crossing and rubbing. Prune when the tree is dormant, between November and February, and be sure to cut back to just above a bud. A long stub left above a cut can be an entry point for disease or dieback.

How to grow Japanese Irises

Iris ensata (syn. Iris kaempferi) is one of the archetypal plants of the Japanese garden. They are rhizomatous, beardless irises, native to East Asia. They have fans of strap shaped leaves and flowering stems 2-4ft tall. They flower in early summer, with two or three large, exotic-looking flowers on a stem, in shades of purple, blue, white, and pink.

They are extremely hardy, down to -20ºC, zone 4 in the US. They will grow in full sun to partial shade, as long as they get at least 6 hours of sun, and like a loose, slightly acidic damp soil with plenty of organic matter. It is especially important in the spring, in the run up to their early summer flowering, that they have plentiful moisture.

They are sometimes sold as marginal plants, and are happy to be grown in shallow water, as long as the crown of the plant is not covered, during spring and summer. However, they need to be lifted out of the water over winter or they are likely to rot. The old foliage should be cut back to the ground in the winter, after it has been knocked back by the first frost.

Iris ensata are heavy feeders and will benefit from a generous feed of a balanced fertiliser for acid-loving plants in the early spring and again after flowering, and a good mulch to help retain moisture. It’s good to add plenty of organic matter to the soil when they are planted or divided, but don’t add fertiliser at this point. Bone meal should be avoided as it is actively harmful to Japanese irises.

It’s very important to divide and transplant Japanese Irises every three to four years to maintain vigour. New roots form above the old each year, so over time the crown of the plant rises above the soil, potentially causing it to fail. To divide, dig up the plant and divide it into individual sections or fans, or slightly larger sections of 2-4 fans each. The oldest roots and rhizomes – the lowest – should be removed, and the foliage cut back to about 1/3 of its length. The divisions should be planted 2-3 inches deep. in fresh soil where Iris ensata has not been grown for the previous three years, and kept well watered. It is best to divide Japanese Irises in spring or autumn, avoiding the heat of mid-summer, though in cooler areas they can be divided immediately after flowering.

Iris ensata have been cultivated in Japan for at least five hundred years, and possibly much longer. Extensive Iris breeding began in the late Edo period, around the 1800s. Japanese Irises were introduced to the West by Carl Thunberg in 1794, and again by von Siebold in the 1850s (as Iris kaempferi). Many varieties have been bred in the United States as well. Some 2000 varieties are now available.

Frogs’ hands and floating clouds – the names of Japanese Maples

One of the classic plants of the Japanese garden is the maple, Acer palmatum. The common Japanese names for maples are ‘momiji’ derived from ‘leaves turning red’ or ‘kaede’ derived originally from ‘frogs’ hands’. Autumn trips to the mountains to see the beauties of the changing leaf colours are called ‘momiji-gari’, maple leaf hunting.

Spring foliage of Acer palmatum ‘Katsura’ (meaning ‘wig’)

There are thousands of cultivars, many with poetic and beautiful names. Here are some Japanese words used in the names of Japanese maple varieties.

Ao – blue-green

Ba – leaves

Beni – deep red

Fu – variegated

Gasa – umbrella

Hime – princess or little

Ito – fine thread

Kin – gold

Koto – a stringed instrument

Maiko – dancing girl

Murasaki – purple

Nishiki – brocade, by extension variegated or textured

Niwa – garden

Ō – large

Ryū – dragon

Sango – coral

Sei – blue-green

Shidare – cascading

Shigure – soft rain

Ukigumo – floating clouds

Yae – double

Yama – mountain