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Iris japonica is a Evergreen Perennial up to 0.60 metres tall.
It is harvested from the wild for local use as a food, medicine and source of materials.
Many plants in this genus are thought to be poisonous if ingested, so caution is advised[
]. The roots are especially likely to be toxic[
Plants can cause skin irritations and allergies in some people[
E. Asia - China, Japan.
], grassy and rocky slopes and among rocks by streams[
Prefers a gritty well-drained soil with plenty of moisture in summer and shelter from early morning sun[
]. Prefers a lime-free soil but succeeds in most good soils[
]. Succeeds in full sun or partial shade[
], but plants flower better in a hot sunny position[
]. Established plants are drought tolerant[
Cultivated for its edible root in Japan[
]. A number of named varieties have been selected for their ornamental value[
It is best to lift the plant in October, store in sand in a cool frost-free place over winter and plant out in March[
Plants have creeping aerial rhizomes that root at intervals[
]. The flowers are susceptible to damage by late frosts, the plants failing to flower after an exceptionally cold winter[
Members of this genus are rarely if ever troubled by browsing deer or rabbits[
Root - the source of an edible starch[
]. Some caution is advised, see the notes above on toxicity.
The rhizome is used in the treatment of injuries[
A decoction of the plant is used in the treatment of bronchitis, internal injuries, rheumatism and swellings[
Plants can be grown for ground cover when planted about 45cm apart each way[
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. 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 after flowering in mid summer. 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.