County Weed Dept. urges public to keep an eye out for Dyer’s Woad

Thursday, June 6, 2019
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Photos by Dana Weatherford
            A Dyer’s Woad plant found in Stillwater County.

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The warmth and sunshine that comes this time of year typically triggers a flood of people looking to enjoy the Stillwater County outdoors. With this increase in recreation comes the increased possibility that noxious weeds will catch a ride on vehicles, equipment, and animals and lay down roots where they do not belong.

The Stillwater County Weed Department is urging people to keep an eye out for a specific noxious weed this summer and fall – Dyer’s Woad.

Although Dyer’s Woad is not toxic, it has the ability to produce thousands of seeds and aggressively over-take native plants in the area. As a non-native weed, the goal is to eradicate Dyer’s Woad before it becomes commonplace. “Early detection, rapid response” is a mantra Stillwater County Weed Coordinator Dana Weatherford said people should keep in mind.

While traveling Highway 10 from Columbus to Park City last week, Weatherford spied three Dyer’s Woad plants. The tall, yellow-flowered weeds were pulled from the ground, the location was marked, and the state Dyer’s Woad Task Force was alerted of its presence in Stillwater County.

Classified as a Priority 1A weed, Dyer’s Woad falls into the most serious category of noxious weeds. According to the Montana Weed Control Association, the Priority 1A classification means the weed is not present or has a limited presence in Montana; if found, such a weed must be eradicated immediately.

Last year, a couple Dyer’s Woad plants were found near Springtime exit west of Columbus. Weatherford said the weed has not returned, but the area is still monitored weekly to ensure it has not resurfaced.


Dyer’s Woad can be controlled through hand pulling or herbicide.

With the identification of Dyer’s Woad in Stillwater County, the statewide Dyer’s Woad Task Force is expected to visit the location in the coming weeks and assist in monitoring the situation, Weatherford explained.

While Stillwater County has the funds to work toward the eradication of Dyer’s Woad, unlike some smaller counties, the state Task Force will principally lend its expertise to ensure the weed does not spread from where it’s found.

Sites on which Dyer’s Woad is located will be monitored for several years following the weed sighting, according to Weatherford.


Dyer’s Woad has small yellow flowers on a long purple stock, and leaves have a white mid-vein splitting them down the middle. The plants can grow to be two to three feet tall, and when the plant is ready to go to seed, the seed pods turn black.

Weatherford said Dyer’s Woad looks similar to the more common weed yellow mustard. Height is an easy way to tell the plants apart – Dyer’s Woad grows to be taller than yellow mustard.

Members of the public who spot Dyer’s Woad are asked to call Weatherford at 322-1106. The Weed Department is offering a $50 reward to those who successfully identify a Dyer’s Woad plant.

She noted that a similar protocol was in place when yellow star thistle was found in the county in 2010.