Photo from Weeds of the West, revised edition.
Photos from Montana Weed Control Association
Growth Habit: Biennial or perennial up to 3 ft. tall.
Leaves: Basal rosette leaves are long with soft fine hairs. Stem leaves alternate, have short basal lobes clasping the stem and without hair.
Stem: Woody, upper portion is branched.
Flower: Small, yellow, 4 - petaled 1/8 inch across.
Roots: It has a thick taproot, which may exceed 5 feet in depth.
Seeds: Plant has many , slightly pear-shaped, winged, black seedpods ½ inch long that hang like ornaments. Each pod contains one seed. One plant can produce 350 to 500 seeds and some plants can produce 10,000 seeds.
Reproduction: By Seed.
Habitat: Dyers Woad can be found along roadsides, disturbed areas, rangeland, and cropland areas.
Biological Control: Native Rust Pathogen (Puccinia thlaspeos)
Herbicides: Metsulfuron in combination with 2,4-D is the most effective.