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University of Wisconsin-Green Bay
Sep 1999 / May 2000
Gary Fewless
Olympus CL 2500L digital camera

European buckthorn

European Buckthorn (Rhamnus cathartica)

European Buckthorn is one of the most troublesome invasive plant species in Wisconsin. As illustrated in the righthand portion of the photo, it forms dense stands within existing native forests and displaces nearly all native plant species with its dense growth. It produces numerous black cherry-like fruits which are eagerly eaten by birds that carry the seeds widely to infest other forests. Although it can invade nearly any forest, the establishment and spread of European Buckthorn is dramatically enhanced by opening the canopy and disturbing the soil as is done in the construction of trails and roads through the forest. European Buckthorn can be recognized by the thorns at the ends of the branches (see photo) and by the abundant black fruits and the dark green leaves that persist until mid to late November, often remaining conspicuous when other trees are bare. There is also a closely related species called "Glossy Buckthorn" (Rhamnus frangula) which is equally invasive, but prefers wetter soils. It differs in having no teeth along the leaf margins and in having shiny leaf surfaces, but produces similar dense stands within our forests as well as in a variety of more open sites.

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Last updated on April 15, 2014