Viola japonica aka Japanese Violet

Viola japonica is also known as Japanese violet. It belongs to Violaceae, the violet family. This perennial comes from temperate East Asia. Its native range spans South Korea, Japan and Taiwan. Japan's records include southwestern Hokkaido, Honshu, Kyushu and Shikoku. It grows in lowland parts of central and southern Japan. Plants For A Future also notes hillsides and damp sites in China. These sites lie beyond the native range Kew gives.

This small plant grows about 0.7 feet [0.2 metres] tall. Its low height suits the front of garden beds. The account gives no mature spread or detailed leaf traits. Plants For A Future lists April as its bloom time. Each flower has both male and female organs. Insects move pollen from flower to flower. The supplied species records give no details of fruit, bark or stems. They give no flower colour or detailed flower shape either.

Grow it in cool soil that stays moist but drains well. It likes soil rich in humus, or decayed plant matter. Give it shelter from winds that scorch. It prefers part shade or shade cast through leaves. The source also lists sites with no shade as suitable. It accepts sand, loam and clay soils with good drainage. It prefers a slightly acid soil, around pH 6–6.5. It tolerates sandstone and limestone soils. But high pH can cause chlorosis, which makes leaves turn yellow. The source gives no hardiness zone for this species.

The plant has food uses as well as garden value. People can eat young leaves and flower buds raw or cooked. They help thicken soups, much as okra does. The roots hold starch and turn slippery when cooked. People also use them in soups and make tea from leaves. Plants For A Future lists no known hazards. This does not prove safety for pets or every possible use. The source reports uses in folk medicine for pain and inflammation. These reports do not prove that such treatments work in clinical use.

Raise new plants from seed or by division. Sow fresh seed in a cold frame in autumn. Sow stored seed there in early spring. Divide plants in autumn or just after they flower. Keep small divisions in light shade while they take root. The source lists no weed potential and names no pests or diseases.