We have included Robinia flava Lour., here as a synonym of Sophora flavescens. Robinia flava is said to be native to northern China, though no species of Robinia are native there. Robinia flava is not mentioned in the Flora of China[], but is included as a synonym of Sophora flavescens in some relatively modern Chinese works such as zhe jiang tian mu shan yao yong zhi wu zhi (see https://www.biodiversitylibrary.org/item/113228)

Common Name: Ku Shen

General Information

Sophora flavescens is a perennial plant with branches that can become more or less woody and persist; it can grow 100 - 200cm tall[].
The plant is harvested from the wild for local use as a medicine and food. It is an important medicinal herb in China, where the plant is sold in local markets[]. The plant is also used as an ingredient in commercial cosmetic preparations.
Sophora flavescens is widely distributed in temperate Asia, it is known to occur in protected areas and the population is believed to be stable at present. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2012)[].

Known Hazards

The plant contains cytosine, which resembles nicotine and is similarly toxic[]. The plant is poisonous when used in quantity[, ].

Botanical References

, ,

Range

E. Asia - Mongolia, Russian Far East, China, Japan, Korea

Habitat

Scrub on mountain slopes, river valleys[], especially on sandy soils[]. Grassy places in lowland and waste ground, C. and S. Japan[]. Scrub, hill slopes, farm fields; at elevations up to 1,500 metres[].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Shrub
Height	1.50 m
Growth Rate	Slow
Pollinators	Insects
Cultivation Status	Ornamental, Wild

Cultivation Details

Although Sophora flavescens is hardy to at least -15°c[], it requires hot summers to fully ripen its wood and so does not do very well in the relatively cool summers of maritime regions, where it gradually weakens and eventually succumbs[]. In such regions it will often succeed if it is treated like a herbaceous perennial, growing afresh from the base each spring[].
Succeeds in a well-drained moderately fertile soil in full sun[]. Found in the wild mainly on sandy soail[]. Requires a warm, sunny position if it is to flower[],
Plants should be container-grown and planted out whilst young, older plants do not transplant well[].
A polymorphic species[].
The flowers are produced on the current years growth[].
Plants in this genus are notably resistant to honey fungus[].
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[].

Edible Uses

Seed[]. (As Robinia flava - see notes above on nomenclature). No more details are given.

Root. Sweet and mucilaginous[], it is used as a food in times of famine[, ]. (As Robinia flava - see notes above on nomenclature).

Medicinal

The root is anthelmintic, antibacterial, antifungal, antipruritic, astringent, bitter, carminative, diuretic, febrifuge, parasiticide, pectoral, stomachic and tonic[, , , , , , ]. It is used internally in the treatment of a range of conditions including jaundice, dysentery, diarrhoea and urinary infections[].
The root is used both internally and externally in the treatment of vaginitis, eczema, pruritis, ringworm, leprosy, syphilis, scabies and itching allergic reactions[].
The root is harvested in the autumn and dried for later use[].

The plant is anthelmintic and diuretic[]. It also has antibacterial activity, inhibiting the growth of Mycobacterium tuberculosis and Trichomonas vaginitis[, ].

Other Uses

The plant is a source of an insecticide and parasiticide[, ]. No further details.

The powdered root is used as an ingredient in commercial cosmetic preparations as a masking agent, abrasive and skin protector[].
Extracts of the roots, and also of the whole plant, are used as ingredients in commercial cosmetic preparations as an antioxidant and skin conditioner[].

Propagation

Seed - best sown as soon as it is ripe in a greenhouse[]. Pre-soak stored seed for 12 hours in hot (not boiling) water and sow in late winter in a greenhouse[]. Prick out the seedlings as soon as they are large enough to handle into individual pots in the greenhouse, and grow them on for 2 years under protected conditions. Plant them out into their permanent positions in early summer of their third year.
Cuttings of young shoots with a heel, mid summer in a frame[].
Air-layering[].