Montana Dyers Woad Project

Dyers Woad (Isatis tinctoria) is native to Southeast Russia and was widely cultivated from the 13th century until 1930 in England as a source of blue dye. Introduced to the United States in the early 1900’s, Dyers Woad was brought to ranches in Siskiyou Co., CA, and Utah through contaminated alfalfa seed from Ireland. In addition to producing a blue dye, this plant has also been used as a medicinal herb in traditional Chinese medicine to treat mumps, throat ailments, hepatitis, headache, and fever. Since its initial introduction, this species has spread throughout the West. Expansion may be due to its adaptation to alkaline soils and arid climates of the West

Growing as a winter annual, biennial, or a short-lived perennial, Dyers Woad establishes along roadsides, in gravel pits, levees, and railroads. Once established the species easily invades well vegetated areas such as rangelands, pastures, forests, waterways, irrigated, and non-irrigated crops. It has been found in elevations as high as 8000 feet. Dyers Woad has an accelerated growth rate, with an ability to grow up to 10 cm or 4 inches in one week. Deep tap roots make it highly competitive and able to dominate plant communities. In addition, Dyer’s Woad is a prolific seed producer, producing an average of approximately 400, but up to 10,000 seeds per plant.

Early detection and rapid response is imperative to the successful control of Dyers Woad in the State of Montana. Dyer’s Woad was first identified in Montana in 1934, since then it has been found in 22 counties. In the 1980’s Extension Noxious Weed Specialist, Dr. Pete Fay, started researching herbicides for use on Dyer’s Woad, and worked with Montana State University students, personnel, and county weed crews to pull Dyer’s Woad and contain the infestations. However, with an expanding Dyer’s Woad population in other states, Montana needed a collaborative strategy for controlling Dyer’s Woad.

The Montana Dyer’s Woad Cooperative Project began in 1997 as a formal entity and has been governed since 2004 by a board known as the Montana Dyer’s Woad Task Force. Funding for the Montana Dyer’s Woad Cooperative Project is provided from the Montana Noxious Weed Trust Fund with matching funds from counties, and the University of Montana. The task force sets and communicates a common statewide goal for Dyer’s Woad management through biannual meetings and review of the 5-year management plan. The Montana Dyer’s Woad Cooperative Project’s overall goal is to eradicate Dyer’s Woad from Montana.

The Project’s specific objectives are to 1) manage known Dyer’s Woad infestations 2) monitor known infestations with GPS units 3) inventory new areas surrounding known infestations for potential spread (satellite populations) 4) educate land managers as well as the public on Dyer’s woad identification and management

Together, these efforts have prevented Dyer’s Woad from becoming a major problem in Montana.

To measure success of the Montana Dyer’s Woad Cooperative Project, the Task Force set the following goals in 2019.

1) Decrease the number of Dyer’s Woad plants found at each site for the next 5 years.

2) Maintain zero plants at the Treasure and Lewis and Clark County sites.

3) Decrease number of plants with goal of zero plants at the Stillwater, Powell, Jefferson, and Silverbow County sites by year 2024.

4) Ensure ≤ 1% of Dyer’s Woad plants produce seed.

Our ability to meet these goals is discussed for each county below.

The summer of 2023, was the twenty-eigth year of an intensive continuing effort to prevent Dyer’s Woad from becoming a major noxious weed problem in Montana. Twelve Montana counties are currently monitored for Dyer’s Woad plants. These include Beaverhead County (Lima and Monida), Missoula County (Mount Sentinel), Park County (east of Livingston and Mill Creek Road), Treasure County (Hyshum), Lewis and Clark County (Helena), Flathead County (Tally Lake Road), Stillwater County (near Columbas), Powell County (south of Deer Lodge), Jefferson County (west of Whitehall), Butte Silverbow County (south of Feeley), Sweetgrass County (south west of Big Timber), and Carbon County (Hwy 310). In general, except the Sweetgrass County location, these sites are along railroads, roads, and creeks where Dyer’s Woad is thought to have spread through vehicle traffic and construction activities.

In 2023, Dyer’s Woad field personnel were hired to monitor the Missoula, Lima, and Flathead sites. These crews regularly monitored their local areas. Found along a US Forest service road, the Flathead County site was monitored by Danner Pickering, who has helped monitor the site since 2019, and was hired in cooperation with the Flathead Conservation District and by forest weed coordinator Tris Hoffman. Amber Burch regularly monitored the Livingston and Snowline sites, provided crew training, conducted site visits at the Sweetgrass, Jefferson, Powell, Lewis & Clark, Butte Silverbow, and maintained records for all sites. Working Dogs for Conservation was contracted for surveying at the Missoula, Beaverhead, Sweetgrass, and Flathead County sites

This season,  Working Dogs for Conservation  searched the Snowline site twice, once early in the season and once later in the fall. Beaverhead County crews visited infestations from mid-May through mid-October. Primary surveyors in Missoula County included both human and dog teams from Working Dogs for Conservation. University of Montana field crews assisted in monitoring this area during their activities within the site. Working Dogs for Conservation surveyed the Flathead site once later in the season. The Stillwater site, identified in 2018, along I-90 west of Columbus by former Dyer’s Woad Task Force Coordinator Monica Pokorny was monitored by Stillwater County Weed Coordinator, Dana Weatherford, and her crew. Treasure County weed coordinator; Jennifer Cramer conducted site visits to monitor the location outside of Hyshum in Treasure County. Individual plants were identified in three locations along interstate right-of-way in 2019. Plants were found in Powell, Jefferson, and Butte Silverbow Counties. These sites were monitored in 2023 by Amber Burch and respective county weed coordinators. In 2019, a large infestation of Dyer’s Woad was identified in Sweetgrass County. This site was monitored and managed by collective efforts of the task force including Sweetgrass County personnel, Amber Burch based out of Beaverhead County, Josh Waggoner, and Jasmine Chaffe from Montana Department of Agriculture, Working Dogs for Conservation, and Carbon County Coordinator, Brian Ostwald. Park County.

At the infestation sites, crews survey the site by walking over the area and using UTV/ATVs. The distance between surveyors is adjusted in the field based on the plant’s growth stage, topography, and associated vegetative cover. Luckily, in the flowering stage Dyer’s Woad can reach 3 feet tall and is easily located. Once a mature plant is found, the area is searched more thoroughly for additional seedlings and rosettes. However, due to many sites having limited flowering plants, surveyors are shifting their focus to finding rosettes. This is done by returning to known locations to look for emerging rosettes. In addition to searching known Dyer’s Woad sites, crews search adjacent and new areas for satellite occurrences. These areas included river and creek banks, railroad right-of-ways, frontage roads, and rangelands.

Once Dyer’s Woad plants were located, plants were hand-pulled, dug, and/or spot-sprayed with 6 oz Milestone, 24-32 oz 2,4-D, and 1 oz/ac Escort® (metsulfuron) plus surfactant. Plants that had bolted and were in the flowering stage, developing, producing seeds, or previously hand pulled at any growth stage, were removed from the site in plastic bags. County weed crews assisted in spraying large or dense infestations where hand-pulling and spot-spraying was impractical. Field crews recorded the number of plants pulled and sprayed per site.

Education is a vital component of the Montana Dyer’s Woad Cooperative Project. The Project works to educate the public, landowners, and land managers throughout Montana about the threat of Dyer’s Woad though field tours and programs, weed pulls, signs, newspaper articles, visiting landowners, flyers, and presentations. In addition, the “Bounty Program” was added to the program in 1998 to assist the Task Force with identification of new plants. A person finding an infestation/plant of Dyer’s Woad not previously identified and more than a half mile from a known population will be paid $50.00.

Task force members participated in sharing Dyer’s Woad information during trainings. The Dyer’s Woad Cooperative Project was presented during the Southwestern Area crew training held in Whitehall, MT. Dyer’s woad information was also shared with Beaverhead County 5th and 7th grade students during an outdoor education event held in May. Amber was also able to share dyer’s woad information and live plant identification to seasonal weed crews working for Beaverhead and Sweetgrass Counties, Red Rocks Lakes Wildlife Refuge, The Nature Conservancy, and Centennial Valley Association. These crew members from TNC, CVA, and Red Rock Lakes are located within the Centennial Valley and help to monitor for dyer’s woad introduction from Idaho through multiple access points including near Henrys Lake and Monida. A presentation is also scheduled for the Flathead Conservation District on November 27th in Kalispell, MT.

The  Working Dogs for Conservation  are involved in management of Dyer’s Woad on Mount Sentinel and provide an excellent avenue to open conversations with individuals utilizing the site for recreation.

Signs were posted at trail access points with information about the project and the dogs, which helped lead discussions with interested parties.

To evaluate the success of the Montana Dyer’s Woad Cooperative Project, participants collect monitoring data. This data includes growth stage when pulled and/or treated. Each plant is recorded as rosette, flowering, or seeding. In addition, infestations and locations have been mapped using EDDMaps and GPS to be included in the state database. At all sites, the number of Dyer’s Woad plants that were in the ripe seed stage when pulled was < 1%. The reduction in Dyer’s Woad numbers in Montana since 2019 (year of largest infestations) is 81%. We do reinforce caution and the need to continue monitoring sites even if at some sites it looks like zero or few plants are being found. Also, in sites where there are remnant roots or seedbanks, in seasons where the weather is conducive, an increase in reported seedlings should be considered based on where at the site those seedlings are found. For example, are the seedlings in new or known sites, within a delineated infested area. Distinguishing between new locations and known locations will help us to better evaluate the success of the project and ensure that plant production from seedbanks don’t inflate the annual tallies and diminish the success of the objectives.

In coming years, we should continue to follow our existing survey, management, and monitoring efforts at all sites. In the future we need to focus on getting the word to land managers, county weed coordinators, and other agency people involved in noxious weed control about the Dyer’s Woad Cooperative Project. It is planned to utilize the detector dogs at the Beaverhead, Missoula, Flathead, Park, and Sweetgrass County sites in 2024. In addition, an aerial and water survey in Park and Sweetgrass counties is also planned for 2024. The task force will also plan to hire, through cooperation with the Flathead Conservation District, an individual to aid in data collection and monitoring at the Flathead County site.

Overall, the Montana Dyer’s Woad Cooperative project continues to be a success due to the number of dedicated participants and diversification of management strategies. Continued support from the Noxious Weed Trust Fund is appreciated.