Berberis thunbergii, the Japanese barberry, Thunberg’s barberry, or red barberry is a species of flowering plant in the barberry family, Berberidaceae, which is native to Japan and Eastern Asia, though widely naturalised in China and North America. Growing to 1 m (3.3 ft.) tall by 2.5 m (8.2 ft.) broad, it is a small deciduous shrub with fruits and green leaves turning brilliant red in autumn, and pale yellow flowers in spring. Numerous cultivars are available as ornamental plants suitable for hedging.
- Japanese barberry has deeply grooved, brown, spiny branches with a single (occasionally tridentine) spine (actually a highly modified leaf) at each shoot node.
- The leaves are green to blue-green (reddish or purple in some horticultural variants), very small, spatula to oval shaped, 12 to 24 mm long and 3 to 15 mm broad.
- They are produced in clusters of 2 to 6 on a dwarf shoot in the axil of each spine. The flowers are pale yellow in colour.
- 5 to 8 mm diameter, produced in drooping 1 to 1.5 cm long umbrella-shaped clusters of 2 to 5; flowering is from mid-spring to early summer.
- The edible fruit is a glossy bright red to orange-red, ovoid berry 7 to 10 mm long and 4 to 7 mm broad, containing a single seed.
- They mature during late summer and fall, and persist through winter.