• Dyers Woad Plant 215x150

Category A Weed

Mustard family (Brassicaceae)

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Dyer's woad (Isatis tinctoria)

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