Purple starthistle (Centaurea calcitrapa)



  • Purple Starthistle Plant 215x150

Category A Weed

Sunflower family (Asteraceae)

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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; known to occur in Pershing County

  • Annual, biennial or perennial; reproduces by seed; older rosettes have a circle of strawcolored 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 or dicamba in the (rosette) stage; apply picloram from (rosette) through mid-bolt stage

Images

Purple Starthistle Plant 215x150
Mature Plant
Purple Starthistle Flower 215x150
Flower
Purple Starthistle Rosette 215x150
Rosette
Purple Starthistle Seed 215x150
Seeds
  Nevada Noxious Weed Field Guide
Nevada Noxious Weed Guide