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

Stem

Stiff, wiry, 1-6 ft. tall and usually branched; wings less than 0.2 in. wide extend down stem

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

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

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

Learn more about the author(s)

Heidi Kratsch

Also of Interest:

Nevada Noxious Weed Field Guide – Yellow starthistle