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

Stem

  • 1-3 ft. tall, stiff, wiry and usually branched; wings less than 0.1 in. wide created by leaf bases that extend down the stem 
Photo of malta starthistle plant with pink and white flowers
 

Leaves

  • Gray-green, 0.75-6 in. long and densely covered with fine hairs; rosette leaves are oval to strap-like (linear) with smooth to deeply lobed edges (margins); stem leaves are alternate, strap-like to oblong with smooth, toothed or wavy edges
Photo of green leaf plant
 

Flower

  • Yellow, located at branch tips or axils in groups of 1-3; base of flower is vase-shaped, 0.3-0.6 in. diameter and covered with cotton-like hairs and stout, purple-to-brown colored spines 0.2-0.6 in. long
Photo of malta starthistle plant with yellow flower and red and pink thorns.
 

Root

  • Shallow taproot
Photo of green malta star thistle plant

Other

  • Grazing, mowing, burning and cultivation can be effective if done prior to seed production
  • Apply 2,4-D, dicamba or triclopyr to actively growing plants; aminocyclopyrachlor, aminopyralid, clopyralid or picloram pre- or post emergence 
 

Control

  • Repeated hand-removal can be effective; disturbances such as fire, tillage and grazing often promote mustard growth.
  • Apply 2,4-D, glyphosate or triclopyr post-emergence; chlorsulfuron or imazapic pre- or post emergence.

Learn more about the author(s)

Heidi Kratsch
Heidi Kratsch
 

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