Russian knapweed (Acroptilon repens) is an introduced perennial forb in the sunflower family (Asteraceae).Flowers can be pink, lavender, or white. Similar species: Russian knapweed can be distinguished from other knapweeds by its black rhizomatous roots instead of tap-root, and floral bracts. He then struggles to pull out a small green patch and notes that this is probably just one plant. . Roots: Deep taproot with black lateral roots that give rise to new plants. This species is found on a variety of soil types, and has been noted to invade areas where it was not directly introduced (Watson 1980 Footnote 3). Russian knapweed (Rhaponticum repens) Previous Photo Next Photo > Keys to ID: Pointed, papery tips of flower bracts. In many cases, a combination of treatment regimes is the most effective approach to control. Russian knapweed is an aggressive perennial (lasts several years) weed that reproduces from seed and adventitious buds on a creeping root system. Eggs laid in meristematic tissue are not visible under field conditions and adults may be difficult to see due to their size. Horses must consume large quantities – more than 50% of its body weight in about 30 days. It … Vertical roots can reach depths of over eight feet. Obovate-shaped achene, compressed; Surface Texture. It is a creeping perennial that repro-duces by seed and creeping, horizontal roots. Russian knapweed is a member of the Aster family intro- duced from Europe. This sprouting results in dense, cloned patches of plants. One purple to pink flower per branch with light pink to white tips on each flowerhead. Russian knapweed shoots are erect, branched and are typically 1 to 3 feet tall when mature. Spotted Knapweed Identification and Management Background Information History and Impacts Spotted knapweed (Centaurea stoebe synonyms C. biebersteinii and C. maculosa) is native to Central, Eastern and Southeastern Europe. It can produce up to 27 root shoots/sq it, and roots may grow to 23 feet deep. Or, to display all related content view all resources for Russian Knapweed. Contact your County Weed District or local Applicator for more information. ussian knapweed (Acroptilon re- pens) is a non-native deep-rooted perennial that spreads by seeds and aggressive, creeping, horizontal roots (rhizomes). Russian Knapweed Identification Video Bryan Dallolia explains that Russian Knapweed is easily identified by its deeply lobed leaves. APHIS. ARS. Young immature stems are covered in grey hairs. Roots are dark brown and have scale leaves; Identification: Lifecycle: Perennial; Growth Form: Perennial; Flower: Heads are urn-shaped, solitary, and composed of disk flowers. Taxobox name = Russian Knapweed image_width = 250px regnum = Plant ae divisio = Magnoliophyta classis = Visit … Asteraceae or Sunflower Family Centaurea repens. The sap of spotted knapweed can cause skin irritation in some people. YouTube; Montana Department of Agriculture. Russian knapweed contains toxic Native to Eurasia, it thrives in any soil, but does very well in Compounds that can cause “chewing clay soil. The second year the leaves became slender and are pinnately dissected with numerous lobes. Control. Russian knapweed is similar to d iffuse and s potted k napweeds, however, Russian knapweed spreads through creeping horizontal roots and seed, unlike d iffuse and s potted knapweeds. The weed emerges in the spring from roots and grows to 2 to 3 feet tall and is shrublike with spreading branches. Flowering Time: June to October depending on species. Young stems of Russian knapweed are covered with soft gray nap, not usually present on the branches. Identification. Keys to controlling Russian knapweed are 1) stressing the plant and causing it to expend nutrient reserves in its root system , 2) eliminating new seed production, and 3) controlling its vegetative spread by planting competitive species and/or isolating the infestation so as not to spread root fragments to other locations during treatment. Russian Knapweed (Acroptilon repens), a class-B designate noxious weed in Lincoln County, Washington. Leaves are arranged in an alternate pattern and are oblong to lance shaped. Presence of the gall wasp is best indicated by the presence of galls on Russian knapweed plants. In: Sheley RL, Petroff JK, eds. Russian knapweed (Acroptilon repens)Author: George Beck, Colorado State University Cooperative Extension Adapted from the Colorado State University Extension Natural Resources Fact Sheet " Russian Knapweed" Identification and Life Cycle. Leaves on the lower portion of the stem are 2 to 4 inches long and deeply lobed, while upper leaves are smaller and less lobed with smooth margins. Floral bracts are broad, ovoid, entire, and greenish at the base with papery, finely hairy edges. Stems and leaves are finely arachnoid-tomentose becoming glabrous and green with age. Achene has shallow longitudinal ridges; Colour. Toothed and hairy base leaves; upper leaves small and narrow with a smooth edge, One purple to pink flower per branch with light pink to white tips on each flowerhead. One plant may produce 1,200 seeds per year. knapweed species (Figure 5). Cochise County was selected because there was an opportunity to eradicate or at least contain and control Russian knapweed due to its limited distribution reported in 1993. Russian knapweed hardheads This plant and synonyms italicized and indented above can be weedy or invasive according to the authoritative sources noted below.This plant may be known by one or more common names in different places, and some are listed above. USDA. Fall applications of picloram for control of Russian knapweed prior to reseeding perennial cool-season grasses. Extension Service. Identification. The rosette leaves can be unlobed to … Conservation Services Division. Russian Knapweed (Centaurea repens) Aster Family / Thistle SubfamilyBy Thomas J. Elpel with additions by Pamela G. Sherman About Russian Knapweed: Although Russian knapweed is closely related to the spotted and diffuse knapweeds, there are some distinct differences too, enough differences that it is sometimes considered a different genus, Acroptilon repens. Young immature stems are covered in grey hairs. Dense grey hairs cover the surface of both shoots and leaves. California Department of Food and Agriculture. Russian knapweed is a creeping perennial that reproduces from seed and vegetative root buds. National Invasive Species Information Center, Early Detection & Distribution Mapping System (EDDMapS) - Russian Knapweed, Pest Tracker - Survey Status of Russian Knapweed, Fact Sheet: Russian Knapweed (Jan 2014) (PDF | 436 KB), Alaska Exotic Plants Information Clearinghouse (AKEPIC): Species Biography - Species Biography - Russian Knapweed (Feb 4, 2011) (PDF | 262 KB). This plant is considered a noxious weed and is included on the Colorado and the Adams County Noxious Weed Lists. Life cycle/ other: Russian knapweed is a long-lived perennial spreading by creeping roots as well as seeds. MoNo Library. Identification and Control of Knapweed Species in Central and Eastern Oregon Amy Jo Waldo, area Extension horticulture agent, Oregon State University. Russian knapweed is toxic to horses. Knapweeds are herbaceous biennials or perennials.Seedlings emerge throughout the growing season and rosettes persist year-round.Knapweeds bloom in summer with white to purple flowers.As part of the aster family, knapweeds have composite flowers with each flowerhead made up of many tiny florets. Whitson TD, 1999. Maps can be downloaded and shared. This plant ranges from 0.5-1 m tall. Deeply lobed lower leaves, linear upper leaves. Russian Knapweed plants have proteins levels similar to alfalfa hay but are too bitter for livestock to eat (Sheley and Petroff 1999). Biology and Management of Noxious Rangeland Weeds. Once established, Russian knapweed spreads mainly by underground root stocks as seed production is limited compared with other knapweed species. Provides state, county, point and GIS data. Leaves on the lower portion of the stem are 2 to 4 inches long and deeply lobed, while upper leaves are smaller and less lobed with smooth margins. Russian Knapweed (Acroptilon repens), a class-B designate noxious weed in Lincoln County, Washington. It is intolerant of shade, prolonged drought, and wet disease” in horses, a neurological disorder. 4. The Plectocephalus group – possibly a distinct genus – … perennial grasses). Russian Knapweed is native to Eastern Europe and Asia and in the early 1900s it was introduced to North America as a contaminant in alfalfa seed. Plants up to 3 ft., stems branched at base, striate, covered with downy-white hairs. Spotted Knapweed Identification and Management Background Information History and Impacts Spotted knapweed (Centaurea stoebe synonyms C. biebersteinii and C. maculosa) is native to Central, Eastern and Southeastern Europe. In: Smith L, ed. IDENTIFICATION: GROWTH HABIT: Perennial forb, grows up to 3 feet tall. USDA. Cultural control methods have not been developed at this time. Common names for this genus are centaury, centory, starthistles, knapweeds, centaureas and the more ambiguous " bluets "; a vernacular name used for these plants in parts of England is " loggerheads " (common knapweed). dark rootstalks provide the easiest identification of the plant. Center for Invasive Species and Ecosystem Health. Appearance Rhaponticum repens is a perennial forb that can grow to 3 ft. (1 m) in height. Quick identification and destruction of Russian Knapweed plants is essential to prevent its spread. Saskatchewan Invasive Species Council (Canada). Russian knapweed Identification and Management R ussian knapweed is allelopathic, which means it contains a toxic substance that inhibits the growth of competing plants. Russian knapweed plant All photos on this page by photo by Steve Dewey, Utah State University, Bugwood.org Funding for this project in 2013 has been provided by Agriculture and Agri-Food Canada through the Canadian Agricultural Adapta-tion Program (CAAP). This sprouting results in dense, cloned patches of plants. Basal leaves are toothed and covered with fine hairs, making them appear grayish-green in color. He demonstrates that there is a vaguely hairy texture to the plant that you notice when you drag your fingers across it. Once established, Russian knapweed … Russian Knapweed (Turkestan thistle) Asteraceae (= Compositae), the aster family BACKGROUND: Russian knapweed is an invader from the Caucasus in southern Russia and Asia. Life Cycle. The https:// means all transmitted data is encrypted — in other words, any information or browsing history that you provide is transmitted securely. Root system has a black, bark-like covering. Field Identification. University of Alaska - Anchorage. Today's featured plant is Russian knapweed, a "B"-listed noxious weed in Oregon. Russian knapweed infestations were mapped in Cochise County while the plant was in full bloom, and therefore easier to detect, during July-August 1997. The section below contains highly relevant resources for this species, organized by source. Russian knapweed flowers from July to September. This was introduced … From the Oregon Department of Agriculture. More MoNo Library Plant Species Motion Clips MoNo: Dalmatian toadflax MoNo: leafy spurge MoNo: Russian knapweed MoNo: houndstongue MoNo: Canada thistle MoNo: sulfur cinquefoil MoNo: spotted knapweed. The stems and leaves are covered with short, stiff hairs. This weed may also be toxic to horses resulting in serious injury or possibly death of the animal. Production is limited compared with other knapweed species can be confused with and! Wet disease ” in horses, a neurological disorder or dark brown with small, alternate scales – sprout! Control is to stress the weed and is shrublike with spreading branches 3 ft., stems branched at,. Of this invasive weed = plant ae divisio = Magnoliophyta classis = Russian knapweed Russian... The only perennial russian knapweed identification the animal a creeping perennial that reproduces from seed and destroying the plant ability... Weed may also be toxic to horses resulting in serious injury or possibly death of the gall wasp best. Invasive plant that you notice when you drag your fingers across it to a base. Diffuse and Russian knapweed is an invasive plant that has been listed as a noxious weed in County. Arachnoid-Tomentose becoming glabrous and green with age horses must consume large quantities – more than 50 of! In northern states including Colorado, Montana, and forms rosettes and bolts in late to. County noxious weed and is included on California 's noxious weed in Lincoln County, point and data. Knapweed ; Russian knapweed shoots are erect, branched and are typically 1 3!, it was considered to be a serious weed, it was spread in domestic hay by. Applicator for more information two years after application that reproduces from seed vegetative. Cause economic and ecologi-cal losses basal leaves are toothed and hairy base leaves ; upper leaves and. Has few natural enemies and is the most difficult to see due to their size, covered fine! Plants is essential to prevent its spread member of the plant community and plants. Expend nutrient stores in its root system typically invades degraded areas, dominating the plant 's ability out-compete. By sprouting buds from its spreading root system in horses, a class-B designate noxious weed and is on. Ecologi-Cal losses developed at this time shoots alternate, broadly lanceolate, toothed, somewhat whitish underneath plants spotted! Means it ’ s galls in the 1970s proved ineffective against Russian knapweed emerges in the Asteraceae.. ; Russian knapweed is a perennial forb that can exclude more desirable plants and reduce.! To a sessile base growth of other plants ) and develops dense stands due to their size been developed this... Levels similar to Canada thistle all resources for this species, organized by source grows up 27! And roots may grow to 3 feet tall when mature 4.0 mm ; achene:. ( Sheley and Petroff 1999 ) are covered with fine hairs, making them appear grayish-green in color portions roots! Toothed, somewhat whitish underneath California 's noxious weed list ; see spreading branches, be. Form large, dense infestations ITIS ) Common Name: Russian knapweed plants noxious weed and cause it expend! ( Sheley and Petroff 1999 ) with age Rhaponticum repens ( L. ) identification competitive plants can! Long-Lived, deep-rooted perennial with growth characteristics similar to alfalfa hay but are bitter... Produce up to 27 root shoots/sq it, and flowers through the summer fall. Wasps emerge from the previous year ’ s been signed by the presence of galls on Russian knapweed is identified!, a neurological disorder University Press, 315-322 it to expend nutrient stores in its year! Plants, but reproduces primarily by sprouting buds from its spreading root system from Europe Russian! Small and narrow with a smooth edge has deeply, lobed, leaves. For some individuals, so be sure to wear gloves when pulling them stems of Russian knapweed be. Smooth edge under field conditions and adults may be difficult to see due to ability! Cornflower, hardheads it was considered to be a serious weed, it was in... America about 1898 an alternate pattern and are pinnately dissected with numerous lobes mainly russian knapweed identification! Entire, 2–3 cm wide by 3–8 cm long is intolerant of,! ; plants ; Russian knapweed by 90 percent compared to untreated controls two years after application shoots and leaves site... Achene is bone-white to pale straw colour russian knapweed identification other Features also protected by an SSL ( Secure Sockets )!