Photographer: Jan Samanek, State Phytosanitary Administration Source: Bugwood.org Copyright: CC BY 3.0 US
The common buckthorn is a shrub that grows from 3-12 feet tall, with many branches. However, it can grow in tree form with a trunk growing up to 10 inches in diameter, and sprouting ascending branches up to 24 feet tall. Stems grow thorns from ½- 1 inch. The leaves are simple, smooth, oval and about 3 inches long with 3 to 5 pairs of leaf veins. Small, green-yellow, 3-4 petaled flowers grow in clusters along the stem. The round and numerous fruits ripen to a purplish black. Unripe fruits have a chemical, emodin, which acts as a laxative.
This plant is able to invade several types of habitats, and it thrives particularly on well-drained soils. Common buckthorn forms dense thickets that crowd and shade out native shrubs and herbs. Also, these dense thickets also prevent the native plants from successfully regenerating. With buckthorns destroying native plant communities, they greatly alter habitats and ecosystems, making it inhospitable to most wildlife.
This plant has also been documented to be an alternate host of the bacteria, crown rust of oats, which impedes oat quality and yield. If common buckthorn infested with crown wilt of oats, were to become established near oat fields it causes severe economic distress on the farmers, landowners, and producers.
Plants are either male or female (dioecious), thus fruiting trees always female. The dark fruits contain 1-4 seeds each, from which new plants sprout. Fruits stay on the plant through winter, but seeds only germinate if the fleshy fruit is eaten or rotted. Common buckthorns can also regenerate from roots and stumps.
In the mid-1800s it was imported from Europe to Minnesota, as an ornamental hedge plant. Due to its numerous fruits being dispersed by birds, it quickly spread throughout the state and the Great Lakes area. Nurseries in Minnesota stopped selling it in the 1930s. It is now present in almost 40 states.
Europe and Western Asia
U.S. Habitat: Varied habitats including roadsides, old fields, savannas and woodlands.
U.S. Present: CA, CO, CT, DE, FL, IA, ID, IL, IN, KS, KY, MA, MD, ME, MI, MN, MO, MS, MT, NC, ND, NE, NH, NJ, OH, PA, RI, SD, TN, UT, VA, VT, WA, WI, WV and WY
For a state and county distribution map provided by EDD MapS click here
The common buckthorn resembles other buckthorn species (Rhamnus sp.), including the less invasive glossy buckthorn (Rhamnus alnus) and the native alder-leaved buckthorn (Rhamnus alnifolia).
There are mechanical, physical and chemical management strategies available for the control of buckthorns. When applying herbicides it is responsive to basal bark and foliar application when using a combination of triclopyr and oil. In fire-adapted areas, prescribed fire is one method that has proven successful, unfortunately that doesn’t apply to most of the plant’s distribution. If trying mechanical methods, it is best done in the spring or summer, especially before fruits are present. Hand-pulling works for saplings, but larger plants may be pulled or cut. Mechanical control is not ideal for massive stands. Be sure to fully remove all roots, and nearby seedlings. Studies have shown that moving 3 or 4 times during a growing season over several years can reduce plant health, but again it only works with smaller stands.
Archibold, O.W., D. Brooks, and L. Delanoy. 1997. An investigation of the invasive shrub European buckthorn, Rhamnus cathartica L., near Saskatoon, Saskatchewan. Canadian Field-Naturalist 111:617–621.
Knight, K.S., J.S. Kurylo, A.G. Endress, J.R. Stewart, and P.B. Reich. 2007. Ecology and ecosystem impacts of common buckthorn (Rhamnus cathartica): a review (PDF | 247 KB) Biological Invasions 9:925-937.
Mascaro, J., and S.A. Schnitzer. 2007. Rhamnus cathartica L. (common buckthorn) as an ecosystem dominant in southern Wisconsin forests. Northeastern Naturalist 14(3):387-402.
Wyckoff, P., R. Jansen, and R. Patten. 2005. The European buckthorn (Rhammus cathartica) invasion in west central Minnesota. Pp. 49–52, In Skinner, L.C. (Ed.). Proceedings: Symosium on the Biology, Ecology, and Management of Garlic Mustard (Alliaria petiolata) and European Buckthorn (Rhamnus cathartica). USDA Forest Service Publication FHTET-2005-09.
Common Buckthorn (PDF | 813 KB)
Iowa Department of Natural Resources.
Invasive Species Best Control Practices - Common Buckthorn (2012; PDF | 2.40 MB)
Michigan Department of Natural Resources. Michigan Natural Features Inventory.