Amur cork tree

Phellodendron amurense — the Amur cork tree — is a large deciduous tree in the family Rutaceae, genus Phellodendron, 10–30 m tall with a trunk up to 1 m in diameter. Its outer bark is thick, spongy, pale grey and deeply fissured into characteristic corky ridges (the genus name Phellodendron means 'cork tree'). The opposite, odd-pinnate leaves are 25–35 cm long with 7–13 ovate to ovate-lanceolate leaflets 6–12 × 2.5–4.5 cm, smooth dark green above, entire-margined with a pointed tip. The tree is dioecious: small greenish-yellow flowers are borne in loose axillary cymes; male flowers have 5–6 stamens and female flowers a 5-chambered ovary. The fruit is a spherical black drupe about 1 cm across in loose clusters, containing 5 seeds. It flowers May–July and fruits September–October; the wood is pale yellow and veined.

Updated by lebachungtdh@gmail.com · 10/12/2026

Phellodendron amurense is native to East Asia: northern and northeastern China (Heilongjiang, Jilin, Liaoning, Inner Mongolia, Shanxi, Hebei, Henan, Anhui), Taiwan, the Korean Peninsula, Japan and the Russian Far East; it grows in mountain forests, valleys and along rivers at 500–1,500 m. The tree is widely planted as a medicinal and ornamental species, and has been introduced and become invasive in parts of North America (Massachusetts lists it as a noxious weed). The trunk bark is harvested year-round (best March–June) from trees about 10 years old, the corky layer scraped off and the bark dried — the drug known as 'huang bai' (黄柏). In traditional Chinese medicine the bark is bitter and cold, entering the kidney, bladder and large-intestine meridians: it clears heat and dries dampness, drains fire and relieves steaming, and resolves toxin and heals sores; it treats damp-heat (leucorrhoea, dysentery, jaundice), consumptive steaming and night sweats, seminal emission, boils, eczema and urinary-tract infections, at 3–12 g per day (raw or stir-fried with salt or wine). Its main constituents are isoquinoline alkaloids — berberine, palmatine, jatrorrhizine, phellodendrine and magnoflorine — together with limonoids (obacunone, limonin) and flavonoids, with antibacterial, antifungal, anti-inflammatory, antipyretic, anti-ulcer, cartilage-protective and prostatic-relaxant activity and potential anticancer effects (lung, prostate). Caution is advised in cold-deficient spleen-stomach; long-term use is not recommended.

Updated by lebachungtdh@gmail.com · 10/12/2026