Arisaema costatum
Family: Araceae
What it is like
Arisaema costatum is a PERENNIAL growing to 0.6 m (2ft) by 0.4 m (1ft 4in). See above for USDA hardiness. It is hardy to UK zone 7. It is in flower from June to July. The species is monoecious (individual flowers are either male or female, but both sexes can be found on the same plant) 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: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in full shade (deep woodland) semi-shade (light woodland) or no shade. It prefers moist soil.
Height (m): 0.6
Where it is found
Wet cool woodlands and cliffs, often forming large colonies. Shrubberies, 2000 - 2600 metres. Grasslands in forest areas at elevations of 2300-2400 metres.
E. Asia - Himalayas in C. and E. Nepal.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 2
Root - cooked. It is boiled, dried and then ground into a powder. The tuber is 3 - 5cm in diameter. Some caution is advised, see the notes above on toxicity.
Root: includes bulbs, corms, tubers, rhizomes etc.
Medicine
Rating: 0
Other
Rating:
How it is grown
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. Plants are nearly hardy in Britain, they normally succeed outdoors in the milder areas of the country. Tubers should be planted about 15cm deep. Only plant out full sized tubers and mulch them with organic matter in the winter. Plants multiply quickly once they are established. Plants need protection from slugs. This species has very large leaves, to 40cm long. Most species in this genus are dioecious, but they are sometimes monoecious and can also change sex from year to year.
Propagating it: 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.
Best place to grow: Woodland Garden Dappled Shade; Shady Edge; not Deep Shade;
Habit: Perennial
Hardiness: 6-9
Growth:
Soil: Light (sandy), medium
Shade: Full shade, semi-shade, no shade
Moisture: Moist
Things to keep in mind
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.