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Figure 1. Several views of Russian knapweed (Centaurea repens). <br />Photo: http://extension.usu.edu/weedweb/ident/Ruskn id htm Available 29 Dec 2005. <br />Russian knapweed primarily regenerates new shoots from dark, scaly, rhizomes several inches <br />below the soil surface. Roots from a recently established plant expand rapidly and may cover <br />up to 12 square yards in two growing seasons. Reproduction via seed is secondary to vegeta- <br />tive reproduction, a trend reflected in the lower rate of spread of Russian knapweed relative to <br />other knapweeds3, but seeds remain viable for two to three years. <br />Long term control of Russian knapweed requires annual evaluations of the infested site and <br />responsive management. The key to Russian knapweed control is to present continual stress <br />and cause the weed to expend belowground nutrient stores. A single control strategy, such as <br />mowing or herbicide application, usually is not sufficient. The best management plan integrates <br />3 Proper identification of Russian knapweed is important because it may be found in the same areas as other knap- <br />weeds, and different control strategies are needed. <br />3 <br />Knapweed, Russian