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

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

Learn more about the author(s)

Heidi Kratsch

Also of Interest:

Nevada Noxious Weed Field Guide – Musk thistle