Phellodendron amurense aka Chinese Corktree

Phellodendron amurense, or Amur cork tree, belongs to the citrus family, Rutaceae. This deciduous tree comes from temperate parts of East Asia. Its range includes the Russian Far East, China, Korea, and Japan. It grows in moist ground near the Amur River. Garden trees reach 30–45 feet [9.1–13.7 metres] tall. Their crowns span 40–50 feet [12.2–15.2 metres]. RHS reports taller trees near 49 feet [15 metres]. A short trunk supports large limbs that spread far outward. Old trees may develop a flat crown.

The bark gives this tree much of its winter value. Mature trunks have thick, soft, corky bark with deep ridges. The outer bark is gray to brown; the inner bark is yellow. The wood resists rot. Brown or gray twigs bear curved, horseshoe-shaped leaf scars. Fine silver hairs cover the winter buds. Leaves grow in opposite pairs and have a pinnate form. Each glossy green leaf has five to eleven leaflets. RHS records as many as thirteen. Soft hairs cover the leaf undersides. Crushed leaves give off a strong smell like turpentine. Fall leaves turn yellow or bronze, but the color fades fast.

Small yellow-green flowers form panicles in May and June. They add little color to the garden. Male and female flowers grow on separate trees. Female trees need pollen from males to set fruit. Their small drupes turn from green to black in fall. The fruit can stay on the branches through winter. Crushed fruit has an unpleasant smell. Birds, squirrels, and other small mammals use the drupes. Fallen fruit can make a mess beneath female trees.

Grow this tree in full sun with room for its crown. It favors deep, rich soil that drains well and stays moist. It accepts many soil types and a wide pH range. Established trees withstand drought and polluted air. Hot summers suit it, though late frost can harm new growth. Chicago Botanic Garden lists USDA zones 3–7; RHS rates it H7. Its growth rate is moderate. It needs little pruning and has few serious pest or disease problems.

The tree provides shade in parks and on large plots. Its low, broad limbs can make street planting awkward. Bark medicines have uses for arthritis and weight loss. The supplied species evidence does not establish food use or toxicity. The tree spreads by seed and can regrow from shoots. It can displace native trees after escaping gardens. Several US states report it as invasive. This risk limits its value as a landscape tree.