European buckthorn USDA PLANTS SYMBOL: RHCA3
Rhamnus cathartica L.
Synonym(s): common buckthorn, European buckthorn

Common buckthorn is a deciduous shrub or small tree that can grow to 25 ft. (7.6 m) in height. The bark is dark gray and the inner bark is orange (easily seen when the tree is cut). Twigs are usually tipped with a sharp spine. The leaf arrangement is usually subopposite, but examples of opposite and/or alternate arrangements are commonly found. Leaves are dark green, oval, 1.5 to 3 in. (3.8-7.6 cm) long, slightly serrate with 3 to 4 pairs of curving veins and a somewhat folded tip. Flowering occurs in the spring, when yellow-green, 4-petaled flowers develop in clusters of 2 to 6 near the base of the petioles. Plants are dioecious (male and female flowers occur on separate plants). Fruits are small, black berries that are 0.25 in. (0.6 cm) in diameter. Common buckthorn invades forests, prairies and savannas in the Midwestern United States and can form dense thickets crowding out native shrubs and understory plants. Once established, it is difficult to remove. Common buckthorn is a native of Europe and was introduced into the United States as an ornamental shrub.

Identification, Biology, Control and Management Resources