Weeds-Dyers Woad

DYERS WOAD Back

Dyers woad behaves as a winter annual, biennial, or short-lived perennial, that reproduces by seed. It is a bluish green plant that normally grows from 1-3 feet tall. Typically, it has a 3 to 5-foot long taproot and some lateral roots, which are located in the upper foot of soil. A member of the mustard family, dyers woad has small yellow flowers. Plants may produce between 350 - 500 seeds. This noxious weed displaces native rangeland species and will reduce forage capacity in a rangeland or pasture situation. This weed uses large amounts of nitrogen, phosphorus, potassium, and water. Plants often start in dry, gravely soil along roadsides. It won't take long for this plant to make its way to range, pasture, and/or cropland.

Control

Mechanical: Hand pulling or digging individual plants can be effective in small or scattered patches. Breaking or cutting the tops is not effective. It will re-grow to produce seed, later in the season.
Biological: A native rust pathogen, Puccinia thlaspeos is known to stunt growth and minimize seed production. The rust is not widespread and does not move well. Sheep grazing provides limited control. Sheep will readily consume the top growth until the plant reaches the flower stage.
Cultural: Cultivation in early spring before seed production or in the fall will destroy new seedlings.
Chemical: Herbicides are more effective if applied before the bolt stage. When applied later, commonly used herbicides appear to do little damage and do not prevent seed production. Products containing chlorsulfuron and metsulfuron have proven effective in rangeland, pastures, and other non-crop areas.

When choosing any kind of control method, assure that your choice is suited for your particular situation. Always read and follow the product label before applying any herbicide.