Malta starthistle (Centaurea melitensis)


Category A Weed

Sunflower family (Asteraceae)

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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

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

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)

Root

  • Shallow taproot

Other

  • Often infests rangeland, pastures, crop fields, waste areas and roadsides; known to occur in Clark, Lincoln and Nye counties

  • Annual; reproduces by seed

  •  Also known as tocalote

Control

  • Grazing, mowing, burning and cultivation can be effective if done prior to seed production

  • Apply aminopyralid, 2,4-D, clopyralid or dicamba from rosette through bolting; apply picloram from rosette through bud stages

Images

Malta Starthistle Flower
Flower
Malta Starthistle Flower 2
Flower 2
Malta Starthistle Rosette
Rosette
Malta Starthistle Seedling
Seedling
  Nevada Noxious Weed Field Guide
Nevada Noxious Weed Guide