Gentiana thunbergii

Gentiana thunbergii is a small gentian. It belongs to the Gentianaceae family. It is native to parts of East Asia. Its range includes China, Japan, Korea, and Manchuria. It is not native to Britain or Ireland. In central and northern Japan, it grows in sunny places. These sites lie in lowlands and in the mountains. RHS lists Gentiana japonica Maxim. as a synonym. RHS also marks the plant's name as unresolved.

This short-lived plant can live for one or two years. PFAF gives its height as about 0.66 feet [0.2 metres]. Its small size suits the garden beds listed for it. The evidence gives no mature width or detailed leaf traits. Flowers bloom from July through September. Seeds ripen from August through October, while flowers still bloom. Each flower has both male and female organs. Bumblebees and butterflies carry pollen between the flowers.

PFAF lists moist soil that drains well for garden growth. The plant accepts sand, loam, and clay soils. It tolerates mild acid and mild alkaline soils, plus neutral soils. It can grow in full sun or light shade. The species account says it prefers sun. It also needs ample moisture below ground in summer. The account reports better growth in northern and western Britain. Take care with the roots, which dislike disturbance. The supplied evidence gives no hardiness zone for this species.

PFAF suggests sowing fresh seed in a bright cold frame. You can also sow in late winter or early spring. Stored seed soon loses its power to sprout. Older seed may take time to sprout, with uneven results. A cold treatment can help seeds sprout. The account suggests a brief moist stage near 10°C first. Follow this with at least five to six weeks between 0°C and −5°C. It also favours clay pots, since they drain better.

PFAF lists leaves as parts people can eat. It describes cooking young plants and flower buds for food. It gives food use a low score: one out of five. The source reports no known hazards. This does not mean the plant is safe. It records no use of this species as medicine. It proposes root use based on other gentians. This does not count as proven use for this species. PFAF reports no other uses and flags no weed potential.