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' "~SUL.27.2001 6~06PM UNITED COMPRNIES Russian knapweed is a creeping perennial that reproduces from seed and vegetative root buds. Russian knapweed emerges in early spring, bolts In May to June, and flowers through the summer into fall. Russian knapweed is,toxic to horses. The key to Russian knapweed control is to stress the weed and cause It to expend nutrient stores in its root system. The best management plan includes cultural controls combined with mechanical and/ or chemical control techniques. n 7 U R n`t. R E 5 0 RANGE by K, George Beck' N0.678 P.34 ~C E 5 ~ S E, R I E S Russian knapweed lgcropNlon repens)15 a creeping, he~aceous perennial of foreign origin that reproduces from seed and vegetative root buds. Shoots, or sterr>s, are erect I18 to 36 inches tale with many branches. Lower leaves are 2 to 4 inches long and deeply lobed; upper leaves are smaller, generally with smooth margins, but can be slightly lobed. Shoots and leaves aze covered with dense gray hairs. The tmt-shaped Flower heads are solitary and occur on shoot Ups; generally 1/4 to 1/2 inches in diameter with smooth papery bracln. Flowers can b¢ pink, lavender ar white. Russian knapweed has vertical and horizontal roots that have a brown to black, scaly appearance, espeaaUy apparent near the crown. This weed forms dense, single special stnrrds overtime due to allebpathy (biochemicals produced by Russian knapweed that Uthibit the growth of other plants) and competition. Phenology, Biology and Occurrence Ruesfan knapweed emerges to early spring, bolts >n May to June (elevation dependent) and Flowers through the summer into fall. Seeds aze produced sparingly (approximately 50 to 500 per shoot) and are viable for two to three years fn soil. Its primary method of reproduction 1s from vegetative propagation with plants produced from seed being of secondary importanoa. Roots from a recently estebllshed Russian knapweed plant expand rapidly and may cover up to 12 squaze yards in taro growing seasons. Rtrsslan knapweed is native to southern Ukraine, southeast Russia, Iran, Itazakhstan, and Mongolia. It grows th these regions on day, sandy or rodty prairies acct sunny meadows, on saline soils, or day, rocky ar sandy shores of lakes and rivers, and on rocky and clay slopes of hills and bottomlands. It Is a weed of cultivated land, dry pastures, end degraded non~ropland (waste places) >n its native ]and. Russian knapweed grows >n most western states and Is toxic to horses, th Washingtcm, it u common on heaviet, often saline soils of bottomlands and grows th pasture.>, hayRelds, gralnifelds and irrigation ditches. M Colorndo, Russian knapweed 1s not restricted to certain soils and occurs in pastures, agronomic sops, roadsides, waste places, and rangeland. Stands may survive 75 years or longer. Management Lke other creeping perenntab, the key to Russian knapweed control R to shrss the weed and cause it to expand nutrient stores in its root system. An integrated management plan should be developed that places continual stress on the weed. Currently, the best management plan includes cultural control combined ® with mechanical and/or chemical control techniques. A single control shategy, ~'goper-eve such as mowing or a herbldde, usually Is not su(fictent. Ek0®eion Russian Imapweed typically Invades degraded areas dominaifng the plant m [olorado stave univerdty community and desirable plant, le.g. perennial grasses). Seeding competitive, Cooperative E~ieneion. sros. perennial grass spades (nalttrral controU after Russian knapweed has been stressed Quick Facts...