Alocasia ringens (Thunb.) Raf.
Arisaema arisanensis Hayata
Arisaema glaucescens (Nakai) Nakai
Arisaema praecox de Vriese ex K.Koch
Arisaema serotinum Miq. ex Franch. & Sav.
Arisaema sieboldii de Vriese ex K.Koch
Arisaema sierotium Siebold ex Regel
Arisaema taihokense Hosok.
Arum ringens Thunb.
Ringentiarum glaucescens (Nakai) Nakai
Ringentiarum ringens (Thunb.) Nakai
Cluster of plants growing in U.C. Botanical Garden at Berkeley - Berkeley, California, USA
Photograph by: James Gaither
Arisaema ringens is a herbaceous perennial plant growing from a tuber that is usually renewed seasonally. The plant produces 2 leaves 15 - 35cm tall and a flowering stem up to 25cm long. The tuber also produces some tubercles around its base - these become separated from the old tuber at the end of the season, growing on in subsequent years to form new plants[
The plant is sometimes harvested from the wild for local use as a medicine. It is often grown as an ornamental in gardens.
The plant contains calcium oxylate crystals. These cause an extremely unpleasant sensation similar to needles being stuck into the mouth and tongue if they are eaten but they are easily neutralized by thoroughly drying or cooking the plant or by steeping it in water.
E. Asia - eastern China, Taiwan, Japan, Korea.
]. Woods near the sea, C. and S. Japan[
|Cultivation Status||Ornamental, Wild
Prefers a cool moist peaty soil in the bog, woodland garden or a sheltered border in semi-shade[
]. Prefers a loamy or peaty soil[
] and will tolerate a sunny position if the soil is moist but not water-logged and the position is not too exposed[
This is probably one of the hardiest members of the genus and should succeed outdoors in a suitable position in many parts of Britain[
Tubers should be planted about 10cm deep[
]. Only plant out full sized tubers and mulch them with organic matter in the winter[
]. Plants need protection from slugs[
Most species in this genus are dioecious, but they are sometimes monoecious and can also change sex from year to year.
The plant is paradioecious. The sex depends on nutrition and is therefore variable from one year to another[
]. Smaller plants produce only staminate flowers, whilst larger plants produce either staminate and pistillate flowers simultaneously or pistillate flowers only. Changes in gender expression are directly correlated with size and are also influenced by the environment in which the plants are growing. Reversions in phenotypic gender have been experimentally induced by such factors as removing leaf area or changing soil nutrient levels[
The tubers of several species in this genus are recorded as being edible after treatment. We have no specific information for this species, but the depressed-globose tuber is 2 - 5cm in diameter[
The root is alterative, febrifuge[
Seed - best sown as soon as it is ripe in a shady position in a cold frame[
]. Stored seed remains viable for at least a year and can be sown in spring in the greenhouse but it will probably require a period of cold stratification. Germination usually takes place in 1 - 6 months at 15°c[
]. When large enough to handle, prick the seedlings out into individual pots and grow them on in light shade in the greenhouse for at least a coupe of years until the corms are more than 20mm in diameter. Plant out into their permanent positions whilst they are dormant.
Division of tubers when the plant dies down in late summer.