Stem

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

Dyer's woad flowering plant

Leaves

Lance-shaped, 1-7 in. long, bluish-green and lack hair (glabrous) with a distinct whitish mid-vein; edges (margins) are wavy to smooth, stem leaves are alternate with lobed base that clasps the stem

Dyer's woad rosette

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, Humboldt 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 to young, actively growing plants; apply aminocyclopyrachor, chlorsulfuron, imazapic or metsulfuronon pre- and post emergence

Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B. 2020, Dyer's woad, Extension, University of Nevada, Reno, Field Guide

Learn more about the author(s)

Heidi Kratsch

Also of Interest:

Dyer's woad