Stem

2-6 ft. tall and sometimes wooly and branched; spiny wings caused by leaf bases that extend down the stem

Photo of musk thistle plant with pink flowers

Leaves

Dark green with a light-green midvein, 4-15 in. long, alternate and sometimes hairy; edges (margins) are deeply lobed and spiny

Flower

Pink to purple (occasionally white), up to 3 in. wide, each located at the tip of a stem; head often nods or droops; stem below head usually spineless
Base of flower is covered with green, purple- or straw-colored, spine-tipped bracts; bracts are 0.1-0.3 in. wide, lance-shaped and sometimes hairy

Root

Deep, fleshy taproot

Photo of musk thistle plants with pink flowers

Other

Often infests roadsides, pastures and waste areas; known to occur throughout Nevada
Biennial; reproduces by seed; also known as nodding thistle

Control

Mowing, tilling or hand removal after bolting but prior to flowering is effective; remove the top 2 in. of crown by digging before seed production
Several biological controls are available
Apply 2,4-D, chlorsulfuron, clopyralid, dicamba, glyphosate, picloram, or triclopyr to young actively growing plants; aminopyralid, imazapic, imazapyr, metsulfuron, or sulfometuron preemergence or post emergence on young plants

Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B. 2020, Nevada Noxious Weed Field Guide – Musk thistle, Extension, University of Nevada, Reno, Field Guide

Extension Associated Contacts

Heidi Kratsch

Also of Interest:


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
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
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
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
Nevada Noxious Weed Field Guide – Yellow starthistle Yellow 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

Garden plant and pest sprayers image by Olga Seifutdinova from Getty Images

Integrated Pest Management

Integrated Pest Management is a strategy that reduces pests to tolerable levels with lower costs for the pest manager or home gardener and minimal effect on the environment. The IPM program at the University of Nevada, Reno focuses on identification and public education with resources for the community including classes, Spanish language web pages and a UNR pest directory.

Master Gardeners of Nevada

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

Weed Warriors Invasive Weed Training

The Nevada Noxious Weed Education Program, Weed Warriors program tackles the growing problem of spreading noxious and nuisance weeds on public and private land.

Nevada Noxious Weed Field Guide – Musk thistle