These tumbleweeds are blown around by the wind therefore spreading seed to un-infested areas. It tends to grow to a height of 3 foot and has a single tap root that can go as deep as 18 inches. Change land use? The biology and North American distribution of spotted knapweed are described in … Print ; Email Print Email. Bracts at the base of each flower head are covered with dark brown or black fringed margins. Flower heads are made up of 40 to 100 purple (or rarely white) ray flowers. Centaurea stoebe subsp. Spotted knapweed was accidentally introduced into North America in the late 1800s in contaminated alfalfa and clover seed and in soil used for ship ballast. registered for use on spotted knapweed. Spotted knapweed is in the genus Centaurea, which, in ancient Greek, means “of the centaur.” Apparently, centaurs are known for having healing powers, and many species in this genus do as well. Spotted knapweed grows 2- 4 feet tall and has a long tap root. Spotted knapweed is a native of Europe and Asia. Spotted Knapweed (Centaurea biebersteinii) FAMILY: ASTERACEAE Description: Spotted Knapweed is a biennial or short-lived perennial with several branched, upright stems growing from a stout taproot and usually grows up to 3 feet tall. Spotted knapweed threatens wildlife habitat and pastures because of its ability to quickly move from disturbed sites into relatively undisturbed, beneficial plant communities. Unless cultural techniques are used, however, the weeds will reinvade. The plant blooms from June to October and consists of multiple stems that hold up to 35 flower heads each. Spotted knapweed was introduced to North America from Eurasia as a contaminant in alfalfa and possibly clover seed, and through discarded soil used as ship ballast. It was probably introduced to North America from Europe as a contaminent in alfalfa seed or in ships' ballast. Spotted knapweed is most often found on disturbed sites such as roads; however, in the Pacific Northwest it is known to invade pastures where it causes the overgrazing of native grasses. Diffuse and spotted knapweed are readily controlled with herbicides. In the Ukraine, spotted knapweed hybridized with diffuse knapweed (Centaurea diffusa) on sites where the two species coexisted. Martyrdom, which the essence addresses, is an interesting paradox for unlike heart-centered selfless service you are instead taking … Uses Top of page Spotted knapweed is nutritious and can be utilized by livestock especially during spring and early summer when plants are green and actively growing in the rosette and bolt stages (Kelsey and Mihalovich, 1987; Popay and Field, 1996). Leaves. It crowds out native species and forage for livestock, and can invade undisturbed native bunchgrass stands. They are both diffuse knapweed. Spotted Knapweed (Centaurea maculosa) Common names: Hayek, Common Knapweed, Martyrdom. There are 24 other non-native species of knapweed within the United States and Canada (Wilson and Randall 2005). squarrosa). Rosettes are formed the first year and appear in early spring as deeply lobed leaves radiating from a common point. Consult your local Agricultural Fieldman or Certified Pesticide Dispenser for more information. This highly invasive plant is found in almost every state in the U.S. and in Canada. Low to moderate use of spotted knapweed by cattle, sheep, goats and some wildlife has been reported (Duncan et al. Other species that can be mistaken as spotted knapweed are species of the Aster family that share habitat with spotted knapweed (Donaldson 2009). Spotted Knapweed : The Strategy - Spotted Knapweed (Centaurea stoebe (maculosa) ssp. Costs of herbicides for controlling knapweed may be prohibitory on large areas. Spotted Knapweed. 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