Centaurea stoebe, the spotted knapweed or panicled knapweed, is a species of Centaurea native to eastern Europe. Knapweed is a dull green plant entirely covered with small, rough hairs. Federal government websites always use a .gov or .mil domain. Previous work, using an activated carbon experiment, suggests allelopathic effects by spotted knapweed on native bunchgrasses (Ridenour and Callaway 2001). Blooms June through July. Learn about the most invasive plants in your local area. Define knapweed. This plant produces chemicals that inhibit nearby plants, reducing diversity in the area and degrading wildlife habitat. Spotted knapweed is an aggressive, introduced weed species that rapidly invades pasture, rangeland, and fallow land and causes a serious decline in forage and crop production. Spotted Knapweed (Centaurea stoebe) 1 Introduction Spotted knapweed (Centaurea stoebe) is a plant belonging to the sunflower (Asteraceae) family.It is a perennial, polycarpic plant, meaning that it lives and flowers for several years Everyone can help win the battle against invasive species. It is often found in heavily disturbed sites, such as roadsides, gravel pits, and edges of agricultural fields, but it moves from those areas into undisturbed pastures, dry prairies, oak and pine woodlands, and rangeland. We protect and manage the fish, forest, and wildlife of the state. After the eggs hatch, the larvae burrow into the root. Horses, cattle, sheep and goats find the plant quite palatable. Methods to control spotted knapweed populations include grazing, cutting and pulling, herbicides and bio-controls. Yellow starthistle is another less robust annual type. Spotted knapweed, as the plant is more formally known, is a national menace, a weed of mass destruction. non Lam. Upright stems are branched at the top and the stems are ribbed, and sometimes as … Diffuse Knapweed ( Centaurea diffusa ) also grows a single, branched stem from a similar looking rosette. Can be a … Both species of Knapweed may readily be distinguished from Thistles by the absence of spines and prickles. It has become a serious problem of pastures and rangeland in the western United States. A single square foot of spotted knapweed can produce 5,000 seeds, which can remain viable for eight years or more. QUICK IDENTIFICATION In early stages of growth, gray-green leaves are deeply lobed with short, thin, grayish hairs A single pink to purple flowerhead at end of stem; racts at the base of flower fringed with short hairs and black on the tips Height up to 6 feet The plant also degrades rangelands, especially in parts of southern BC. Classification Click on a scientific name below to expand it in the PLANTS Classification Report. Definition of spotted knapweed : a knapweed (Centaurea maculosa synonym C. biebersteinii) with usually pink flowers and deeply cleft leaves that is native to Europe and Asia but is now widespread in the U.S. Its leaves are slightly hairy and decrease in size towards the top of the stem. Persistent pulling or digging can control spotted knapweed (Duncan et al. There are five invasive knapweed species in Canada, unintentionally introduced from Europe in … It can form dense cover in prairies, pastures, and open habitats. Spotted knapweed is a perennial with several branched upright stems growing from a stout taproot; usually to 5 feet tall. Spotted knapweed prefers to grow on well-drained, light to coarse soil and does not tolerate dense shade or constant moisture. Runoff, erosion, and sedimentation increase, harming streams and aquatic creatures. In past times, young women wore spotted knapweed flowers to … Flowers are small, thistlelike, and light purple to pinkish purple or rarely white. Questions about your donation? It is a threat to pastures and dry ecosystems including prairies and dunes. NCC hosts Conservation Volunteers events to control spotted knapweed populations. Finally, dead plant material can increase fire risk. For example, it is estimated that Montana loses 4.5 million dollars annually in recreation, forage, and costs related to knapweed control. Local Concern: Spotted knapweed is poisonous to other plants, creating barren areas where only knapweed grows. spotted knapweed CEMA4 Centaurea maculosa auct. Crowds out native species and forage for livestock (Zouhar 2001) The .gov means it’s official. Call 1-800-392-1111 to report poaching and arson, More Wildflowers, Grasses and Other Nonwoody Plants. A species profile for Spotted Knapweed. Do an audit of your yard to ensure none are growing on your property. Although spotted knapweed is found in most Canadian provinces and one territory (BC, Alberta, Saskatchewan, Manitoba, Ontario, Quebec, New Brunswick, Nova Scotia and Yukon), it grows mainly in southwestern Canada. Spotted knapweed, a class-B non-designate noxious weed in Lincoln County, Washington (Centaurea biebersteinii) is of the Asteraceae family. In Montana knapweed was actually spread on purpose by airplane by beekeepers as it is an excellent honey plant. Visit our FAQ page. By the end of its first year, a knapweed plant is a small basal rosette. The diversity of nonwoody vascular plants is staggering! In a few years it can overtake and replace pasture grasses, native plants, and even other aggressive weeds such as sericea lespedeza. For example, it releases a chemical that hinders native plants’ root growth and displaces vegetation. A large, conspicuous insect, it lays its eggs on the top of the knapweed's root crown. 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