It is a rhizomatous perennial plant, with pale blue, lavender or white flowers with an orange or yellow crest.

[3] The leaves are generally described as evergreen,[10] and grow in a broad fan,[9] with arching tips.

[4] The stems have 3–5 spathes (leaves of the flower bud), which are lanceolate,[4] and 9.5–2.2 cm (4–1 in) long.

Junipergenin B (Dalospinosin) can be found in the leaves of Juniperus seravschanica and the roots of Iris japonica.

[14] As most irises are diploid, having two sets of chromosomes, this can be used to identify hybrids and classification of groupings.

Findings include 2n=54, Kazuao, 1929; 2n=34,36, Simonet, 1932; 2n=36, Sharma & Tal., 1960; 2n=36 Kurosawa, 1971; 2n=31,33,54, Chimphamba, 1973; 2n=54, Mao & Xue, 1986; 2n=28,34,36,54, Colasante & Sauer, 1993; 2n=28, Dong et al. 1994; 2n=28 to 60 and Yen, Yang, & Waddick, 1995.

Plants growing wild in Japan were counted as 2n=54 for infertile triploid forms.

[15] It has the common names of 'fringed iris',[12] 'Shaga' (in Japan),[16] and butterfly flower (in China).

[17] It is written as 蝴蝶花 in Chinese script,[3] and known as hu die hua in Pidgin in China.

The Latin specific epithet japonica refers to from Japan, even though the plant is thought to have originated in China.

[17] It was introduced to Europe in 1792 from China, by Thomas Evans of the East India Company.

Though it can be found in woods across Japan that appear wild, the plant's existence often indicates that the area used to be inhabited by humans and was abandoned[20] It is found in China, within the Chinese provinces, of Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hainan, Hubei, Hunan, Jiangsu, Jiangxi, Qinghai, Shaanxi, Shanxi, Sichuan,[5] Tibet, Yunnan, and Zhejiang.

[21] I. japonica grows on forest margins,[3] in wet grasslands (or meadows),[3] among rocks by streams,[12] and along hillsides,[9] or rocky slopes.

[11] However, an extremely cold winter (or late frosts) may adversely affect the flowering of this species,[12] and the foliage becomes tatty,[23] or browned.

[26] It has average water needs during the growing season,[7] wet or damp conditions during the winter may cause the root to rot.

[9] The stems and dead leaves should be removed after flowering to keep the plant tidy and help it, for next years growth.

[4] The plants are rested in summer (after the spring flowering), and then started again in the late autumn.

If it cannot be grown in a cool house, it should be given a sheltered position, with shrubs where it is protected from the morning sun.

[11] It does not have any serious disease or insect problems,[7] but pests (such as thrips, slugs and snails), occasionally damage plants by feeding on the flowers or foliage.

Smaller clumps should be potted and grown in a cold frame until there have formed sufficient roots to survive, they then can be planted in the Spring.

[1] Like many other irises, most parts of the plant are poisonous (rhizome and leaves), if mistakenly ingested can cause stomach pains and vomiting.

[5][12] In Japan, the iris was encouraged or planted on the tops of hills, within castles, the slippery fans of the iris leaves were used to slow marauding invaders to allow defending armies to protect the castle.