Common Name:

General Information

Arisaema heterophyllum is a herbaceous perennial plant growing from a tuber that is usually renewed seasonally. The plant produces a usually solitary leaf 30 - 60cm tall and a flowering stem 50 - 80cm tall. 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 harvested from the wildf for local use as a medicine. It is the potential source of a pesticide and is also an important ornamental, being much esteemed in Japan for its appearance as well as its ease of culture[].
Due to forest clearing, the wet conditions required by this species are becoming rare, and in Japan it is considered a threatened species, where it has been listed in the national plant Red-Data Book. It is found over a wide area in China, however. Overall, the plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

None known

Botanical References

Range

E. Asia - throughout China except Xizang, Taiwan, Japan, Korea

Habitat

Forests, thickets, grasslands; at elevations up to 2,700 metres[]. Often found in riparian deciduous and evergreen forest and more open areas along watercourses[].

Properties

Conservation Status	Least Concern
Medicinal Rating
Other Uses Rating
Habit	Perennial
Height	0.65 m
Pollinators	Insects
Cultivation Status	Ornamental, Wild

Cultivation Details

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, does not dry out but is not water-logged and the position is not too exposed[, , ].
Only plant out full sized tubers and mulch them with organic matter in the winter[]. Plants need protection from slugs[].
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[].

Edible Uses

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 3 - 6cm in diameter[, ].

Medicinal

The tubers are used to treat coughs, epilepsy, and tetanus[].

Other Uses

Agglutinin extracted from the plant has shown promise as an effective candidate for the control of peach potato plant aphid[].

Propagation

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.