Dyer's woad (Isatis tinctoria)


Category A Weed

Mustard family (Brassicaceae)

Helpful Links

List of all Photo Credits

Stem

  • Up to 4 ft. tall; branched at top; dry plants with attached seed pods remain standing into winter

    Leaves

    • Lance-shaped, 1-7 in. long, bluish-green and lack hair (glabrous) with a distinct whitish midvein; edges (margins) are wavy to smooth

    • Stem leaves are alternate with lobed base that clasps the stem

      Flower

      • Yellow with 4 petals; occur in clusters that give plant a flat-topped appearance

      • Mature seed pods dark brown to black, oblong, flattened and suspended from a small stalk; each contains a single seed

        Root

        • Deep taproot

          Other

          • Grows well on a broad range of sites; often infests waste areas, roadsides, rangeland, pastures and crop fields; known to occur in Elko, Washoe and White Pine counties

          • Biennial, but sometimes annual or perennial; reproduces by seed

          • Historically cultivated for use as a blue dye and as a medicine

            Control

            • Mow in early-flower to reduce seed production; spring tillage or digging individual plants prior to seed production can be effective

            • Apply 2,4-D, metsulfuron, chlorsulfuron or imazapic to young, actively growing plants

              Images

              Dyer's woad mature plant
              Mature Plant
              Dyer's woad Rosette
              Rosette
              Dyer's woad Infestation
              Infestation
              Dyer's woad Leaves and stem
              Seed Pod
                Nevada Noxious Weed Field Guide
              Nevada Noxious Weed Guide