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The Mission of the Yellowstone County Weed Department is to assist the public, private, and other government agencies to manage and control existing noxious weed infestations as well as to prevent new invasive species from infesting Yellowstone County.
Dyers WoadIsatis tinctoria
Photo from Weeds of the West, revised edition.
Photos from Montana Weed Control Association
Video Supplied By Montana Weed Control Association
| Attribute | Description |
|---|---|
| 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. |