Hoary cress (Cardaria draba)


Category C Weed

Mustard family (Brassicaceae)

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Stem

  • 0.5-2 ft. tall; branched near top; covered with short hairs

    Leaves

    • Alternate, 1-4 in. long, blue-green, oblong to lance-shaped and covered with short hairs; edges (margins) are toothed to smooth

    • Lower leaves have short leaf stems (petioles); bases of upper leaves have lobes that clasp the stem

      Flower

      • White with 4 petals; occur in clusters that give plant a flat-topped appearance; occur from spring to early-summer

      • Seed pods are oval to heart-shaped; each contain 2 seeds

        Root

        • Deep, spreading root system

          Other

          • Grows best in disturbed, alkaline soils; often found in pastures, fields, roadsides, rangelands, waste areas and along waterways; known to occur in all Nevada counties

          • Perennial; reproduces through roots and seeds

          • Also know as whitetop; three species occur in Nevada: hoary cress (C. draba) is most common but lens- podded whietop (C. chalapensis) and hairy whiterop (C. pubescens) also occur

            Control

            • Dig or pull individual plants for small infestations; remaining roots can produce new plants

            • Frequent tillage or mowing for several years can reduce plant density

            • Apply 2,4-D to actively growing plants prior to bud stage; chlorsulfuron or metsulfuron frombud to early bloom; imazapic from full bloom until necrosis

              Images

              Hoary Cress Plant
              Mature Plant
              Hoary Cress Infestation
              Infestation
              Hoary Cress Leaves on stem
              Leaves on stem
              Hoary Cress Rosette
              Rosette
              Goat's Seed pod
              Seed pod
              Nevada Noxious Weed Field Guide
              Nevada Noxious Weed Guide