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NOW KKnowkWo to War* GSU Rkwaim - N wl Rte, WCO <br />4-H /Youth Agriculture Famiiy/c+onsumer H9rt ut ure. Natural Resources Nutrition Resources Home <br />no. 3.111 <br />Russian Knapweed <br />by K.G. Beck 1 <br />Quick Facts... <br />• Russian knapweed is a creeping <br />perennial that reproduces from <br />seed and vegetative root buds. <br />• Russian knapweed emerges in <br />early spring, bolts in May to <br />June, and flowers through the <br />summer into fall. <br />• Russian knapweed is toxic to <br />horses. <br />• The key to Russian knapweed <br />control is to stress the weed <br />and cause it to expend nutrient <br />stores in its root system. <br />• The best management plan <br />includes cultural controls <br />combined with mechanical <br />and/or chemical control <br />techniques. <br />Russian knapweed (Acroptilon <br />repens) is a creeping, herbaceous <br />perennial of foreign origin, that <br />reproduces from seed and vegetative <br />root buds. Shoots, or stems, are <br />erect, 18 to 36 inches tall, with many <br />branches. Lower leaves are 2 to 4 <br />inches long and deeply lobed. Upper <br />leaves are smaller, generally with ` <br />smooth margins, but can be slightly <br />lobed. Shoots and leaves are covered <br />with dense gray hairs. The solitary, <br />urn-shaped flower heads occur on <br />shoot tips and generally are 1/4 to <br />1/2 inch in diameter with smooth <br />papery bracts. Flowers can be pink, Figure 1: Russian knapweed. <br />lavender or white. Russian knapweed <br />has vertical and horizontal roots that have a brown to black, scaly appearance, especially <br />apparent near the crown. <br />The weed forms dense, single species stands over time due to competition and <br />http://www.ext.colostate.edu/pubs/natres/031 I I . html 6/20/2005