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. LT of MN Extension-INFO-U: Buckthorn Control Page 1 of 2 <br /> ��C�, g <br /> CJ:�iIVERS�'t'Y�7F MINPiESUTA <br /> ��r1rFv �,'��11S1C�11 <br /> ��a� <br /> 5M <br /> Buckthorn Control <br /> There are three Rhamnus species, known as buckthorn in Minnesota. <br /> . Dwarf Alder, R. alnifolia, is native from northern Minnesota to the Twin Cities. It is <br /> small, about four feet by four feet and is found in tamarack swamps and wet <br /> meadows. It is not invasive in its natural range. <br /> . Glossy Buckthorn, R. frangula, is from Europe. It grows to about 20 feet, has alternate <br /> buds, red fruit that turns dark at maturity and is irregular in shape. It aggressively <br /> invades wetlands and moist woodlands. Columnar forms in the nursery trade are <br /> narrow and upright, growing to 12 feet high. <br /> . Common or European buckthorn, R. cathartica, is extremely aggressive on lowland <br /> and upland sites. It grows to 20 feet with a spreading irregular crown. The bark is <br /> rough gray/brown. The fruit is glossy black and the leaves are finely toothed, pointed <br /> and a glossy, dark green. Diagnostic characteristics include prolific berry clusters and <br /> leaves that stay dark green well into winter. Common buckthorn is widely distributed <br /> in Minnesota and is very common in the understory of urban and rural woodlots. <br /> CONTROL <br /> Buckthorn control is labor intensive. Strategies include one or more of the following: <br /> . Mechanical removal where plants are sparse is the most expedient and <br /> environmentally friendly method. Dig, pull or chop the plants out of the ground. <br /> Buckthorn pulls out most easily up to 3/8 inch caliper or diameter. Buckthorn doesn't <br /> re-sprout from underground roots. <br /> . Crown removal without chemical treatment eliminates fruit, however, stumps re- <br /> sprout. Re-sprouting stumps can be treated with foliar sprays or with fire for several <br /> growing seasons. <br /> . Fire is most effective against seedlings and small saplings. Be aware of local and <br /> state fire codes and local permits and ordinances. <br /> CHEMICAL CONTROL <br /> . Cut stumps can be chemically treated. Cut the buckthorn trunk as low to the ground <br /> as possible before treating. Several products, including Tordon RTU, Garlon and <br /> Roundup can be purchased without a special license. ALWAYS READ THE LABEL <br /> AND FOLLOW DIRECTIONS when applying any chemical. <br /> . Basal bark treatment allows application of chemical to the lower bark of the tree <br /> without cutting the top. Garlon 4 is the preferred herbicide for basal bark treatment. <br /> For more information, contact your local Extension office or the Minnesota Department of <br /> Agriculture, Division of Agronomy/Plant Protection at 651-296-3343 and request MDA fact <br /> sheet FS-PM-BCKTN-01. <br /> http://www.extension.umn.edu/info-u/environment1BD516.html 5/14/O 1 <br />