Stem

  • Stiff, wiry, 1-6 ft. tall and usually branched; wings less than 0.2 in. wide extend down stem
Photo of yellow starthistle leaves

Leaves

  • Blue- to gray-green, 1.5-6 in. long and densely covered with fine hairs
  • Rosette leaves are oval to strap-like (linear) with deeply lobed edges (margins); stem leaves are alternate, strap-like to oblong with smooth to wavy edges
Photo of yellow starthistle flower

Flower

  • Yellow, located singly at branch tips or axils; base of flower is vase-shaped, 0.5-0.75 in. diameter and covered with cotton-like hairs and stout, straw-colored spines 0.5-1 in. long
Photo of yellow starthistle plant

Root

  • Deep taproot
 

Other

  • Infests rangeland, pastures, croplands, waste areas and roadsides; known to occur in Carson City, Douglas, Elko, Humboldt, Lander, Lyon, Storey, Washoe, and White Pine counties
  • Annual; reproduces by seed
  • Causes “chewing disease” in horses by damaging the area of the brain that controls fine motor movements, particularly of the mouth, resulting in starvation or dehydration 
 

Control

  • Grazing, mowing, burning, pulling, digging and cultivation can be effective if done prior to seed production
  • Several biological control agents are available 
  • Apply 2,4-D, dicamba, or triclopyr rosette to bolt; glyphosate bolt to flowering; aminocyclopyrachlor, aminopyralid, clopyralid or picloram preemergence to rosette; chlorsulfuron preemergence
Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B. 2020, Nevada Noxious Weed Field Guide – Yellow starthistle, Extension, University of Nevada, Reno, Field Guide

Learn more about the author(s)

 

Also of Interest:

 
Photo of canada thistle plant.
Nevada Noxious Weed Field Guide – Canada thistle
Canada thistle is a noxious weed that has been identified by the state of Nevada to be harmful to agriculture, the general public, or the environment. Learn more about this weed.
Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B. 2020, Extension, University of Nevada, Reno, Field Guide
Photo of malta starthistle plant with yellow and pink and red flowers
Nevada Noxious Weed Field Guide – Malta starthistle
Malta starthistle is a noxious weed that has been identified by the state of Nevada to be harmful to agriculture, the general public, or the environment. Learn more about this weed.
Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B. 2020, Extension, University of Nevada, Reno, Field Guide
photo of perennial sowthistle patch
Nevada Noxious Weed Field Guide – Perennial sowthistle
Perennial sowthistle is a noxious weed that has been identified by the state of Nevada to be harmful to agriculture, the general public, or the environment. Learn more about this weed.
Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B. 2020, Extension, University of Nevada, Reno, Field Guide
Photo of purple starthistle
Nevada Noxious Weed Field Guide – Purple Starthistle
Purple starthistle is a noxious weed that has been identified by the state of Nevada to be harmful to agriculture, the general public, or the environment. Learn more about this weed.
Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B. 2020, Extension, University of Nevada, Reno, Field Guide
Photo of iberian starthistle plant with pink flower on top
Nevada Noxious Weed Field Guide – Iberian starthistle
Iberian starthistle is a noxious weed that has been identified by the state of Nevada to be harmful to agriculture, the general public, or the environment. Learn more about this weed.
Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B. 2020, Extension, University of Nevada, Reno, Field Guide
 

Associated Programs

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Master Gardeners of Washoe County

Master Gardeners provide free, research-based horticulture information to Nevadans.

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Master Gardeners of Nevada

Program trains local gardeners to provide research-based horticulture information to Nevadans

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Integrated Pest Management

Integrated Pest Management program is a long-term management strategy that uses a combination of tactics to reduce pests to tolerable levels with potentially lower costs for the pest manager and minimal effect on the environment.