Botanical Name: Arisaema amurense
Common Names: Tian Nan Xing
Habitat: Arisaema amurense is native to E. Asia – N. China, Japan, Korea. It grows in the virgin forests, mountains and river banks. Deciduous forest, mixed forest, under woods and by streams at elevations of 50 – 200 metres in China.
Arisaema amurense is a perennial plant growing to 0.5 m (1ft 8in) by 0.5 m (1ft 8in).This species from Manchuria has triple-divided, crisped edge leaves and a purple-ended, emerald green spathe broadly lined with white.
The inflorescence emerges at the same time as the leaves and is generally green in colour, often with vertical white or pale lines. Sometimes these can be reddish maroon. The inside of the spathe can be more brightly coloured with darker horizontal bands. The spathe limb is relatively short and tends to be held mostly horizontal.
There are usually two leaves, each with up to five leaflets. Younger plants can show leaves with three leaflets, whilst older and more mature plants will have five. Some clones have very attractive serrated or undulated leaf margins.
Individuals are either male or female and never bisexual.
The species is dioecious (individual flowers are either male or female, but only one sex is to be found on any one plant so both male and female plants must be grown if seed is required). and is pollinated by Flies. The plant is not self-fertile.
Suitable for: light (sandy) and medium (loamy) soils and prefers well-drained soil. Suitable pH: acid, neutral and basic (alkaline) soils. It can grow in full shade (deep woodland) semi-shade (light woodland) or no shade. It prefers moist soil.
Prefers a cool 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 species is well suited to the front of a peat border. Tubers should be planted about 15cm deep. Only plant out full sized tubers and mulch them with organic matter in the winter. Plants require protection from slugs. Most species in this genus are dioecious, but they are sometimes monoecious and can also change sex from year to year.
Well-soaked roots can be boiled, peeled and eaten. The tuber is 6 – 7cm in diameter. Some caution is advised, see the notes above on toxicity. Young leaves – cooked. Some caution is advised, see the notes above on toxicity.
Arisaema amurense has been used in Chinese herbal medicine for thousands of years and is valued especially for its beneficial affect upon the chest. When prescribed internally it is always used dried and in conjunction with fresh ginger root. The root is an acrid irritant herb that is anodyne, antibacterial, antifungal, antiphlogistic, antirheumatic, anticancer, antispasmodic, antitumor, expectorant, sedative and stomachic. The dried root is used internally in the treatment of coughs with profuse phlegm, tumours, cervical cancer, epilepsy, tetanus and complaints involving muscular spasms. The fresh root is applied externally as a poultice to ulcers and other skin complaints. The root is harvested when the plant is dormant in the autumn or winter and is dried for later use
Known Hazards :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.