Dyer's woad also inhibits the growth of competing plants. Stunted root growth is especially evident in other mustard species and further aids dyer's woad establishment. Together, these characteristics allow dyer's woad to successfully displace native vegetation. In Montana, our goal is to contain dyer's woad, reducing existing large infestations and eradicating all small infestations. Control of dyer's woad can be accomplished through manual, mechanical or chemical means.
Hand pulling is the most effective method of controlling small infestations.
Eradication of dyer's woad will require persistent and intensive monitoring from year to year. Since dispersal is solely dependent on seed production, it is important to carry flowering plants out of the area because they may continue to produce seeds even after they are pulled. This treatment provides about two seasons of control. Metsulfuron should not be applied to open water, nor while water is present in wetlands. It is permissible to treat seasonally dry flood plains, marshes, swamps and transitional areas.