Coptis chinensis aka Chinese Goldthread

Coptis chinensis, or Huang Lian, is an evergreen perennial in the buttercup family, Ranunculaceae. Kew places its native range in central and east-central China. Plants For A Future lists a wider range, including Assam and northern Myanmar. It grows in damp conifer woods, bogs, and shaded valleys. Reported sites lie at elevations of 1,640–6,560 feet [500–2,000 metres]. These habitats give useful clues to its garden needs.

This small plant reaches about 1 foot [0.3 metres] tall. Its spread is about 0.7 feet [0.2 metres]. It keeps its leaves through the year. Kew describes its growth form as perennial or rhizomatous. Flowers appear from February to March, before the seeds ripen in April and May. Each flower has both male and female organs. Insects pollinate the flowers. The supplied species evidence gives no further detail on flower or fruit form.

Choose moist, humus-rich soil with a slightly acid reaction. Light shade or a north-facing site suits its stated growing needs. Plants For A Future also lists growth without shade. It accepts sandy, loamy, and clay soils, and prefers moist to wet ground. The source reports hardiness to at least 5°F [−15°C] and lists USDA zones 5–9. Its small size suits woodland beds, shaded edges, and bog gardens. Gardeners can also use it as ground cover in a peat garden.

Raise plants from fresh seed or divide them in spring. Sow ripe seed in acid compost under greenhouse cover. Germination may take one to six months at 50°F [10°C]. Stored seed may benefit from four weeks of cold treatment. Keep young plants in a shaded greenhouse through their first winter. Move them outdoors in spring or mid-autumn. The supplied evidence names no specific pests or diseases. Plants For A Future does not flag it as weedy.

The roots have a long role in Chinese herbal medicine. They taste very bitter and contain a yellow pigment used for dye. Traditional uses include treatments for pain, fever, spasms, and digestive complaints. These reports do not establish safe or effective home treatment. Plants For A Future records no known edible uses. It reports no confirmed toxicity specific to this species. However, it urges caution because many plants in its family are mildly toxic.