Dyers Woad
(Isatis tinctoria)

Photo from Weeds of the West, revised edition.

Rosetta	Root	Stem
Leaf	Bloom	Seed

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.

 

Video Supplied By Montana Weed Control Association