Japanese Barberry

Japanese barberry (Berberis thunbergii, Berberidaceae) is a dense, rounded deciduous shrub from Japan and eastern Asia, typically 3 to 6 feet tall and 4 to 9 feet wide. Small obovate leaves (1.3 to 3.2 centimeters) appear in clusters along thorny stems with single spines at each node. Foliage ranges from green to blue-green or reddish-purple depending on cultivar, turning orange, yellow, and red in fall. Yellowish flowers appear in spring, followed by small red ellipsoid berries that persist into winter. The species is classified as invasive in multiple North American jurisdictions, spreading by seed dispersal, creeping roots, and stem layering.

Japanese barberry performs best in full sun on well-drained soil and adapts to a wide range of soil types except wet or poorly drained conditions. It tolerates drought, deer browse, clay soil, and erosion once established, with a minimum root depth of 18 inches. Documented diseases include leaf spot, rust, leaf scorch, and powdery mildew. Pest associations include lecanium scale, aphids, soft scale, Indian wax scale, and twobanded Japanese weevil. Notable cultivars include 'Crimson Pygmy' (compact dwarf with deep red-purple foliage), 'Aurea' and 'Sunsation' (golden foliage, 3 to 4 feet), 'Kobold' (green, 2 feet), and 'Golden Nugget' (1 foot). OSU documents additional forms including var. atropurpurea and trade selections such as Lustre Green and Bonanza Gold.