Sophora flavescens aka Shrubby Sophora

Sophora flavescens is a shrub in the pea family, Fabaceae. Its common names include Ku Shen and yellow mountain laurel. It is native from Siberia across eastern Asia's temperate regions. Records list Mongolia, China, Korea, Japan, Taiwan, and eastern Russia. It grows in scrub on mountain slopes and in river valleys. In Japan, it also grows in grassland and disturbed ground. Some wild sites have sandy soil.

This shrub grows slowly and has an upright form. Plants for a Future gives a garden height of 5 feet [1.5 metres]. It gives a spread of about 3.3 feet [1 metre]. This source calls it evergreen: it keeps leaves all year. Its yellow flowers draw butterflies. Chicago Botanic Garden lists blooms from May to June. Plants for a Future lists July to August instead. Thus, bloom times can vary from site to site. Each flower has both male and female organs. Insects pollinate the flowers. Seeds ripen in September.

Grow this shrub in full sun with good drainage. It likes moist soil with a moderate level of nutrients. It grows in sand, loam, and clay soils. It also accepts mildly acid, neutral, and mildly alkaline soil. Chicago Botanic Garden lists USDA hardiness zones 6–8. Plants for a Future gives cold tolerance to about 5°F [−15°C]. Yet surviving cold alone does not ensure success in Britain. Cool summers can weaken plants until they die. Warm sites help the wood mature before winter. A sunny wall with shelter can help plants flower.

In mild parts of Britain, plants may regrow from the base each spring. Gardeners can use them as hedges, screens, or single specimen plants. A sunny woodland edge is another suggested place to grow them. The plant draws birds as well as butterflies. It can fix nitrogen. Grow new plants from seed, summer heel cuttings, or air-layering. Sow fresh seed in a greenhouse once it ripens. Protect young seedlings before planting them out in early summer.

People in China have long used the root as medicine. Reported uses include treating skin complaints and problems with digestion. These past uses do not make the plant safe to eat. Plants for a Future lists no known edible uses. The plant contains cytisine, a poison with effects like nicotine. Larger amounts can cause poisoning. Sources also note its use against insects and parasites.