|buckthorn (Rhamnus spp.)||
buckthorn (Rhamnus spp.; BUCKTHORN FAMILY [Rhamnaceae]) Four species: 2 relatively small and inconspicuous natives, and 2 larger Eurasian species which are described here. Tall shrubs or small trees (20-25’) usually with few to several stems arising from the base. Grey to brown bark with prominent lenticels. Alternate (sometimes opposite) ovate-elliptic leaves emerge very early in the spring and stay green long into fall and winter. Prolific clusters of ¼” red-to-black fruit ripen in late summer and fall. Introduced as ornamental hedges, common buckthorn and glossy buckthorn have become aggressively invasive in many Wisconsin habitats where they crowd out native vegetation. 
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