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

Stem

Up to 4 ft. tall, stiff, highly branched, bushy and covered with hairs; NO wings on upper stems

Leaves

Alternate; 4-8 in. long, mostly pinnate-divided, covered with short grayish hairs and dotted with resin

Flower

Pink to purple, each located at the tip of a branch; base of flower is vase-shaped, 0.75-1 in. long, 0.25 in. wide and covered with stout, straw-colored spines 0.4-1 in. long

Root

Deep, stout taproot

Other

Grows best in sites with heavy, fertile soils; often infests rangelands, waste areas and roadsides; not known to occur in Nevada
Annual, biennial or perennial; reproduces by seed; older rosettes have a circle of straw-colored spines at the center
Closely resembles Iberian starthistle in everything except seed; seed of Iberian starthistle has plume of bristles extending from one end, purple starthistle does NOT

Control

Mowing plants in bud to flower stage can reduce seed production; repeated hand removal can be effective; DO NOT burn
Apply 2,4-D, clopyralid, dicamba, or glyphosate in the rosette stage; aminocyclopyrachlor, aminoyralid, picloram or sulfometuron preemergence to rosette stage

Learn more about the author(s)

Heidi Kratsch

Also of Interest:

Nevada Noxious Weed Field Guide – Purple Starthistle