buckthorns

Buckthorns are a group of shrubs and small trees in the family Rhamnaceae. The term commonly covers several species in the genera Rhamnus and Frangula, including the common buckthorn (Rhamnus cathartica) and the glossy buckthorn (Frangula alnus). In some classifications, Frangula is treated as distinct from Rhamnus.

Most buckthorns are deciduous, growing to 2–6 meters tall, with simple, oval leaves, small white or greenish flowers in loose panicles, and bluish-black berries that ripen in late summer or autumn. The fruits are bitter and can be laxative, particularly in Rhamnus cathartica.

Native to Europe and western Asia, several buckthorn species have become invasive in North America, where they form dense thickets that shade out native understory plants and alter woodland dynamics. Their berries are dispersed by birds, aiding spread.

Management focuses on preventing spread, removing seedlings and small shrubs by hand, cutting and treating stumps with herbicide, and restoring native vegetation after removal.

Taxonomy and notes: The classification of buckthorns is unsettled, with some species placed in Rhamnus and others in Frangula; both groups share similar traits and ecological impacts.