Rhamnus cathartica (Common Buckthorn)

Rhamnus cathartica, commonly known as Common Buckthorn, is a deciduous shrub or small tree native to Europe. It has dark green elliptical leaves and produces clusters of small greenish-white flowers in spring, followed by black berries in the fall. This species is considered invasive in many parts of North America due to its ability to outcompete native plants and form dense thickets.