Iris tectorum
Roof Iris
Taxonomy and growth
Uses
Toxicity
Toxicity warning. The historical record reports a hazard for this plant. Do not use it to decide which parts are safe to eat or use medicinally.
Many plants in this genus are thought to be poisonous if ingested, so caution is advised[12]. The roots are especially likely to be toxic[9]. Plants can cause skin irritations and allergies in some people[9].
Edible uses
Root - an edible starch is said to be extracted from it[6][2][3]. Some caution is advised since there are reports that the plant might be poisonous. Perhaps the extracted starch is edible.
- Plant part
- Root
Environment
- Range
- E. Asia - China, Japan.
- Habitat
- Grows wild on shady rocky slopes and in scrub, it is also found planted on thatched roofs in Japan. Forest margins, sunny banks, meadows, damp places, beside water to 3500m[10].
- Light
- full sun
- Shade tolerance
- light shade
- Water
- moderate
- Hardiness
- Zone 6+
- Soil textures
- sandy, loamy
- Soil pH
- acid, neutral, alkaline
- Drainage
- well drained
- Tolerances
- drought
- Tolerates Nutritionally Poor Soil
- No
- Drought
- tolerant
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.
Cultivation
Prefers a well-drained loam rich in leafmold with plenty of moisture in summer and an open sunny position[1][11][13][7]. Requires a really well-drained soil that is dry rather than damp, and a hot sunny position[8]. Prefers a lime-free soil but succeeds in most good soils and in partial shade[13]. Succeeds in dry soils and, once established, is drought tolerant[5]. Cultivated for its edible root in Japan[6]. There are some named varieties, selected for their ornamental value[8]. In China the plants are grown on the roofs of houses[5]. Plants do not flower so freely in cultivation in Britain. In their native habitat they experience cold dry winters and warm wet summers[4]. 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[1]. Members of this genus are rarely if ever troubled by browsing deer or rabbits[8].
References
F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press 1951-00-00
Tanaka. T. Tanaka's Cyclopaedia of Edible Plants of the World. Keigaku Publishing 1976-00-00
Kunkel. G. Plants for Human Consumption. Koeltz Scientific Books 1984-00-00 ISBN 3874292169
Phillips. R. & Rix. M. Perennials Volumes 1 and 2. Pan Books 1991-00-00 ISBN 0-330-30936-9
Chatto. B. The Dry Garden. Dent 1982-00-00 ISBN 0460045512
Hedrick. U. P. Sturtevant's Edible Plants of the World. Dover Publications 1972-00-00 ISBN 0-486-20459-6
Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992-00-00 ISBN 0-333-47494-5
Thomas. G. S. Perennial Garden Plants J. M. Dent & Sons, London. 1990-00-00 ISBN 0 460 86048 8
Bown. D. Encyclopaedia of Herbs and their Uses. Dorling Kindersley, London. 1995-00-00 ISBN 0-7513-020-31
Flora of China 1994-00-00 http://flora.huh.harvard.edu/china/
Grey. C. H. Hardy Bulbs. Williams & Norgate. 1938-00-00
Frohne. D. and Pf�nder. J. A Colour Atlas of Poisonous Plants. Wolfe 1984-00-00 ISBN 0723408394
Innes. C. The World of Iridaceae