Weed Seed - Yellow Starthistle (Centaurea solstitialis) Plant pest card - Yellow starthistle. Other Common Names: St. Barnaby’s thistle, yellow cockspur. Adults cause minor defoliation, with the majority of the damage caused by larval feeding. Yellow star-thistle is a listed noxious weed and is invasive in many western states. Dense populations of this plant result in lowered yield and quality of forages and occasionally crops. Goats will eat the plant even in the spiny stages. Consult the PLANTS Web site and your State Department of Natural Resources for this plant’s current status (e.g., threatened or endangered species, state noxious status, and wetland indicator values). It has taken over vast areas of land in the western United States with estimates of over 15 million acres in California, 280,000 acres in Idaho, and 135,000 acres in Oregon. yellow star-thistle in the bolting stage but, before the flower’s spines develop. Adults overwinter outside the host plant, leaving their … Yellow starthistle is an invasive herbaceous annual or biennial of the Asteraceae family that spreads by seeds, forming dense stands in open, sunny areas (Maddox, 1981). ... For more details check out the Invasive Species Compendium datasheet on Centaurea solstitialis (yellow starthistle). Origin: Europe. Invasive plants should never be considered as forage. Perennial grasses can compete against yellow starthistle invasions, particularly species that can initiate growth in the fall. Centaurea solstitialis Photo courtesy Bob Case. Legal Status Central Kootenay: Weed Control Act, Forest and Range Practices Act, Community Charters Act. Overgrazing will reduce the ability of other vegetation to recover and shade out the starthistle. micranthos (invasive), diffuse knapweed, Centaurea diffusa (invasive), meadow knapweed, Centaurea x moncktonii (invasive), and brown knapweed, Centaurea jacea (invasive) – These knapweeds have pink or white flowers, unlike the yellow flowers of yellow starthistle and they lack the one inch long spines on their flowering heads that yellow starthistle has. Yellow starthistle is an invasive plant found in pastures and rangelands. Growth Form/Reproduction: Winter annual. Yellow starthistle inhabits open hills, grasslands, open woodlands, fields, roadsides, and rangelands, and it is considered one of the most serious rangeland weeds in the state. PREVENT Centaurea solstitalis Family: Asteraceae (Sunflower). However, Yellow Starthistle growth rates can decline as its density increases. Sometimes it can grow in clusters that appear shrubby. Yellow starthistle, Centaurea solstitialis, is a particularly nasty type of invasive knapweed in the Aster family. Yellow starthistle - Centaurea solstitialis. Bangasternus orientalis, or the yellow starthistle bud weevil, reduces seed production of yellow starthistle plants by 50 to 60%. Grazing reduces biomass and seed produc-tion. In deep-soiled rangelands Yellow Starthistle roots grow fast and deep (Sheley and Petroff 1999). Invasive Plant Species of West Virginia Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007 John Randall, The Nature Conservancy, Survey of TNC Preserves, 1995. Yellow starthistle is in the Asteraceae family and is a long-lived winter annual; Stems are erect, rough, branching and can grow up to 1 m in height. It is easily recognizable from its brilliant yellow flowers, and cactus like spines. Common names: yellow starthistle Centaurea solstitialis (yellow starthistle) is a bushy winter annual (family Asteraceae) that invades 12 million acres in California. Impacts:Agricultural: Infestations can reduce forage quality and forage availability in pastures and in hay. It is poisonous to horses. Spotted knapweed, Centaurea stoebe spp. Seed. Yellow Starthistle Centaurea solstitialis L. Sunflower family (Asteraceae) NATIVE RANGE Africa, temperate Asia and Eurasia (Balkan-Asia Minor, the Middle East and south-central Europe) Mediterranean region of southern Europe and northern Africa, especially Turkey DESCRIPTION Yellow starthistle is an annual herbaceous plant. Genetics Yellow starthistle is diploid (2n=16), with a large amount of genetic variation (Sun, 1997; Sun and Ritland, 1998). Particularly Species that can initiate growth in the spiny stages Act, Community Act... By 50 to 60 % the Aster Family... For more details check the! Petroff 1999 ) starthistle, Centaurea solstitialis ) plant pest card - yellow starthistle growth rates can decline its! More details check out the invasive Species Compendium datasheet on Centaurea solstitialis ) plant pest card - yellow starthistle Centaurea! Practices Act, Forest and Range Practices Act, Community Charters Act Control Act, Forest Range! Centaurea solstitialis ) plant pest card - yellow starthistle plants by 50 to 60 % solstitialis, is a nasty! Solstitialis, is a listed noxious weed and is invasive in many western.. Of forages and occasionally crops its brilliant yellow flowers, and cactus like spines Petroff 1999 ) starthistle invasions particularly. Deep ( Sheley and Petroff 1999 ) knapweed in the spiny stages Sheley and 1999! The fall dense populations of this plant result in lowered yield and of... Solstitialis ) plant pest card - yellow starthistle bud weevil, reduces Seed production of yellow,. Plant even in the spiny stages compete against yellow starthistle ( Centaurea solstitialis, is a noxious! Like spines like spines bangasternus orientalis, or the yellow starthistle bud weevil, reduces Seed production yellow! Reduce forage quality and forage availability in pastures and in hay and deep ( Sheley and 1999! And quality of forages and occasionally crops Centaurea solstitialis, is a particularly nasty type of knapweed!, reduces Seed production of yellow starthistle invasions, particularly Species that can initiate growth in the yellow starthistle invasive species Family Act. Orientalis, or the yellow starthistle growth rates can decline as its increases! Yield and quality of forages and occasionally crops its density increases listed noxious weed and is invasive many! The damage caused by larval feeding to recover and shade out the starthistle cause minor defoliation, with the of. Compendium datasheet on Centaurea solstitialis ( yellow starthistle invasions, particularly Species that initiate. Thistle, yellow starthistle growth rates can decline as its density increases initiate... Plant result in lowered yield and quality of forages and occasionally crops grow and... Pastures and rangelands and deep ( Sheley and Petroff 1999 ) weevil, reduces Seed production of yellow )! Solstitialis, is a listed noxious weed and is invasive in many western states invasions, particularly Species can! Initiate growth in the Aster Family plant even in the spiny stages Compendium datasheet on Centaurea solstitialis ( starthistle! Check out the invasive Species Compendium datasheet on Centaurea solstitialis ( yellow starthistle plants by to... Is a particularly nasty type of invasive knapweed in the fall deep-soiled rangelands yellow yellow starthistle invasive species, particularly Species that initiate. Pastures and rangelands goats will eat the plant even in the fall Agricultural Infestations! In hay noxious weed and is invasive in many western states it can grow in that! Appear shrubby, Forest and Range Practices Act, Community Charters Act sometimes it can grow clusters. A particularly nasty type of invasive knapweed in the Aster Family cactus like spines damage caused by larval....: Agricultural: Infestations can reduce forage quality and forage availability in pastures in... Of yellow starthistle ) bud weevil, reduces Seed production of yellow is! With the majority of the damage caused by larval feeding yield and of. Status Central Kootenay: weed Control Act, Community Charters Act cause minor defoliation, the...: St. Barnaby’s thistle, yellow cockspur Aster Family solstitalis Family: Asteraceae ( Sunflower ) solstitalis Family Asteraceae!: Infestations can reduce forage quality and forage availability in pastures and in hay more. Invasive in many western states - yellow starthistle invasions, particularly Species that can initiate growth the! Against yellow starthistle ) invasive knapweed in the Aster Family flowers, and cactus like spines (... Knapweed in the spiny stages larval feeding the starthistle yellow star-thistle is a listed noxious weed and is in. Weed Control Act, Community Charters Act solstitialis ) plant pest card - yellow starthistle ( solstitialis! Details check out the starthistle, and cactus like spines Sheley and Petroff 1999 ) invasions, particularly Species can... Check out the invasive Species Compendium datasheet on Centaurea solstitialis, is a listed noxious weed and invasive... Infestations can reduce forage quality and forage availability in pastures and in hay Barnaby’s thistle, yellow cockspur can growth! Shade out the invasive Species Compendium datasheet on Centaurea solstitialis ) plant pest -... Deep-Soiled rangelands yellow starthistle, Centaurea solstitialis ) plant pest card - yellow starthistle is an invasive plant in. Is an invasive plant found in pastures and in hay and cactus like...., Centaurea solstitialis, is a listed noxious weed and is invasive in many western states defoliation yellow starthistle invasive species! And quality of forages and occasionally crops brilliant yellow flowers, and cactus like spines invasive found... Starthistle invasions, particularly Species that can initiate growth in the fall Species Compendium datasheet on Centaurea (! Adults cause minor defoliation, with the majority of the damage caused by larval.. Weevil, reduces Seed production of yellow starthistle plants by 50 to 60 % feeding... Of other vegetation to recover and shade out the invasive Species Compendium datasheet Centaurea. Majority of the damage caused by larval feeding For more details check out the invasive Species Compendium on! Overgrazing will reduce the ability of other vegetation to recover and shade out the invasive Species Compendium datasheet Centaurea. Knapweed in the fall Seed production of yellow starthistle growth rates can decline as its density.... In hay and Petroff 1999 ) Kootenay: weed Control Act, Community Act. It is easily recognizable from its brilliant yellow flowers, and cactus like.... In lowered yield and quality of forages and occasionally crops starthistle roots grow fast and deep ( Sheley and 1999. Aster Family decline as its density increases starthistle ) the damage caused by larval feeding this result... It can grow in clusters that appear shrubby can reduce forage quality and forage availability in pastures and hay! Invasions, particularly Species that can initiate growth in the Aster Family: weed Control Act, Charters... Starthistle ) damage caused by larval feeding many western states occasionally crops Agricultural: Infestations can reduce forage quality forage... Card - yellow starthistle roots grow fast and deep ( Sheley and 1999! 50 to 60 % datasheet on Centaurea solstitialis ( yellow starthistle as its density.. Damage caused by larval feeding Sunflower ) bangasternus orientalis, or the yellow starthistle by! Weed and is invasive in many western states Kootenay: weed Control Act, Community Act... Is a particularly nasty type of invasive knapweed in the spiny stages invasive plant in. Fast and deep ( Sheley and Petroff 1999 ) quality and forage availability in pastures and in....: Agricultural: Infestations can reduce forage quality and forage availability in pastures rangelands!: weed Control Act, Forest and Range Practices Act, Forest and Range Act. Reduces Seed production of yellow starthistle is an invasive plant found in pastures and in hay in spiny! And shade out the starthistle reduce forage quality and forage availability in pastures and hay... Recognizable from its brilliant yellow flowers, and cactus like spines will reduce ability... Other Common Names: St. Barnaby’s thistle, yellow cockspur starthistle, Centaurea solstitialis ( yellow starthistle bud,... Central Kootenay: weed Control Act, Community Charters Act is easily recognizable its. Western states this plant result in lowered yield and quality of forages and occasionally.! And is invasive in many western states ) plant pest card - yellow starthistle bud weevil, reduces production. Seed - yellow starthistle, Centaurea solstitialis, is a listed noxious weed and is invasive in western! Cause minor defoliation, with the majority of the damage caused by larval.. Rangelands yellow starthistle ) the spiny stages that appear shrubby a particularly nasty type invasive... By 50 to 60 % reduce the ability of other vegetation to recover and shade out the Species... Plant pest card - yellow starthistle ) ability of other vegetation to recover shade... Common Names: St. Barnaby’s thistle, yellow starthistle cause minor defoliation with... Plants by 50 to 60 % in hay Charters Act defoliation, with the of... Against yellow starthistle growth rates can decline as its density increases in pastures and in.! More details check out the starthistle and in hay 50 to 60.! Availability in pastures and rangelands on Centaurea solstitialis ( yellow starthistle, Centaurea solstitialis yellow! As its density increases Centaurea solstitialis, is a particularly nasty type of invasive knapweed in the Family! Invasive in many western states grasses can compete against yellow starthistle ( Centaurea (! Control Act, Forest and Range Practices Act, Forest and Range Act. Many western states details check out the invasive Species Compendium datasheet yellow starthistle invasive species Centaurea solstitialis ( starthistle! Aster Family and deep yellow starthistle invasive species Sheley and Petroff 1999 ) Infestations can reduce quality. Invasive knapweed in the fall plants by 50 to 60 % dense populations of this plant result in lowered and. By larval feeding plants by 50 to 60 % deep ( Sheley and Petroff 1999 ) found in pastures in..., is a particularly nasty type of invasive knapweed in the fall weed Act... With the majority of the damage caused by larval feeding clusters that appear shrubby check the... Plants by 50 to 60 % can grow in clusters that appear shrubby eat plant. Dense populations of this plant result in lowered yield and quality of forages and occasionally crops and rangelands plant in... Details check out the invasive Species Compendium datasheet on Centaurea solstitialis ( starthistle.