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Rangeland -Pasture Recommendations <br />Russian knapweed Identification and <br />Management <br />Russian knapweed (Centaurea repens) is a non-native deep-rooted <br />perennial that spreads by seeds and aggressive, creeping, horizontal roots <br />(rhizomes). The roots are black with a scaly appearance. Russian knapweed can <br />grow up to 3 feet in height. The stems and leaves are covered with short, stiff <br />hairs. The flowers are urn -shaped, pink to purple in color, and are solitary at the <br />tips of the upper branches. Russian knapweed can be distinguished from other <br />knapweeds by the pointed papery tips of the bracts that surround the flowers. <br />Russian knapweed emerges from its root system in early spring after soil <br />temperatures remain above freezing. It produces flowers from June to August <br />and sets seed in later summer to early fall. Russian knapweed reproduces <br />primarily from its root system. Buds on the horizontal roots can form <br />adventitious shoots that may grow to be independent plants. Russian knapweed <br />can be managed with herbicides or insects, but long-term control must include <br />planting competitive plant species to occupy bare ground once infested by the <br />weed. f <br />Russian knapweed is allelopathic, which means it contains a toxic <br />substance that inhibits the growth of competing plants. This weed may also be <br />toxic to horses resulting in serious injury or possibly death of the animal. Russian <br />knapweed displaces native vegetation and reduces forage values on range and <br />pasturelands. It can infest many land types, from roadsides, ditch banks, riparian <br />zones, pastures, irrigated cropland, clearcuts, and cropland. <br />The most effective method of control for Russian knapweed is to prevent <br />its establishment through proper land management. Maintain healthy pastures <br />and rangeland and continually monitor your property for new infestations. <br />On the backside of this sheet are Russian knapweed management <br />recommendations. If you have any questions, please contact the Weld County <br />Public Works Dept., Weed Division at (970) 304-6496 ext. 3770. Please visit our <br />website www.weldweeds.org. <br />