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

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

Learn more about the author(s)

Heidi Kratsch

Also of Interest:

Nevada Noxious Weed Field Guide – Dyer's woad