Iris tectorum
Maxim.
Roof Iris, Wall iris, Japanese Roof, White Root Iris
(c) 非常豹, some rights reserved (CC BY-NC), uploaded by 非常豹
(c) Yuri Pirogov, some rights reserved (CC BY-NC), uploaded by Yuri Pirogov
(c) Bob Gutowski, some rights reserved (CC BY-NC-SA)
What to Eat
Edible parts: Root
Root - an edible starch is said to be extracted from it. Some caution is advised since there are reports that the plant might be poisonous. Perhaps the extracted starch is edible.
Known Hazards
Where to Find It
E. Asia - China, Japan.
TEMPERATE ASIA: China (Anhui Sheng, Fujian Sheng, Gansu Sheng, Guangdong Sheng, Guangxi Zhuangzu Zizhiqu, Guizhou Sheng, Hainan Sheng, Hubei Sheng, Hunan Sheng, Jiangsu Sheng, Jiangxi Sheng, Shaanxi Sheng, Shanxi Sheng, Sichuan Sheng, Xizang Zizhiqu, Yunnan Sheng, Zhejiang Sheng), Korea TROPICAL ASIA: Myanmar (possibly)
How to Identify
Iris tectorum is an evergreen Perennial growing to 0.3 m (1ft) by 0.5 m (1ft 8in) at a medium rate. See above for USDA hardiness. It is hardy to UK zone 6. It is in leaf all year, in flower from May to June. The species is hermaphrodite (has both male and female organs) and is pollinated by Insects. The plant is 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 semi-shade (light woodland) or no shade. It prefers dry or moist soil and can tolerate drought.
How to Grow
Prefers a well-drained loam rich in leafmold with plenty of moisture in summer and an open sunny position. Requires a really well-drained soil that is dry rather than damp, and a hot sunny position. Prefers a lime-free soil but succeeds in most good soils and in partial shade. Succeeds in dry soils and, once established, is drought tolerant. Cultivated for its edible root in Japan. There are some named varieties, selected for their ornamental value. In China the plants are grown on the roofs of houses. Plants do not flower so freely in cultivation in Britain. In their native habitat they experience cold dry winters and warm wet summers. It is best to lift the plants in October, store them in sand in a cool frost free place over winter and replant in March. Members of this genus are rarely if ever troubled by browsing deer or rabbits.
Propagation: Seed - best sown as soon as it is ripe in a cold frame. Stored seed should be sown as early in the year as possible in a cold frame. Stored seed does not require cold conditions in order to stimulate germination. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in the greenhouse or cold frame for their first year. Plant out into their permanent positions in late spring or early summer. Division, best done in July/August after flowering. Very easy, larger clumps can be replanted direct into their permanent positions, though it is best to pot up smaller clumps and grow them on in a cold frame until they are rooting well. Plant them out in the spring.
