The following article is courtesy of MSU News Service
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WEED WORK TAKES THE WOES OUT OF THE WOAD
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August 05, 2005 -- By Carol Flaherty
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| Marijka Wessner, the weed education specialist for Missoula County, pulls dyer's woad during a Montana Native Plant Society dyer's woad pull there. File photo courtesy of Monica Pokorny. |
Monica Pokorny has documented a trillion plants that won't bloom in Montana next year, but she's not shedding a single tear over their absence.
That's because the missing plants will all be dyer's woad, a noxious weed Montanans have been working to contain. Pokorny's work, and mission, is finding and eliminating the weed. She says it's fine for the weed to thrive in its native southeastern Russia. She just doesn't want it in Montana, where woad spreads on dry rocky ground and crowds out whole communities of native shrubs, flowers and grasses.
Pokorny works on a grant-funded project at Montana State University with weed scientist Jim Jacobs. As a part of that, you'll find Pokorny and her team scouting for dyer's woad from mid-May to the end of October. When they find a plant or infestation, they note its location by global positioning system coordinates and either pull what they find, spray it or alert weed supervisors that work is needed at the site.
In Montana, woad is known to have escaped from a University of Montana pharmaceutical garden in 1934. Dyer's woad populations increased in Utah, Idaho and Montana before it was targeted for control, Pokorny says. Eventually, it spread to 14 Montana counties, but has been eliminated in all but four of those, largely due to the efforts of members of the Montana Dyer's Woad Cooperative Project. The project is funded by the Montana Noxious Weed Trust Fund.
The project also funds a $50 bounty paid to anyone who finds a previously undocumented dyer's woad site. With that incentive, occasional plants are found in isolated areas throughout Montana.
"We can easily get rid of isolated plants, but one plant can generate hundreds in a single year, which is why we have the bounty," Pokorny said.
The trillion-plant estimate is not just an idle number. Pokorny has tried to estimate the potential spread of dyer's woad if Montanan's had not been pulling weeds and occasionally spraying through the years. The numbers become so huge that she doesn't begin with the 62,000 plants pulled by teams in the Lima area in 1980s. Using just the dyer's woad removed between 1999 and 2004, each with an average of 400 seeds per plant (woad can make up to 10,000 seeds per plant) and adding in the average number that germinate, mature and make new seeds, Pokorny got well above the one trillion mark.
Acreage saved by the team's efforts is harder to estimate. Montana would have nothing but woad if all the averages were reality. But whether the estimates are accurate or not, containment has been effective, which is a hugh accomplishment that Pokorny says she hopes land managers will keep in mind.
"Weed management takes persistence," Pokorny says. "To have persistence, you have to know that it works, that your effort is worthwhile."
The work takes a lot of eyes and hands. Members of the Montana Native Plant Society help with two weed pulls each year near Missoula. The combined efforts of groups from MSU, UM, the Bureau of Land Management, Extension Service, county weed districts and kids out scouting for woad in hopes of earning the bounty, have been effective. As near as Pokorny can figure, she and her crew of two pull about 2,000 to 3,000 plants a year at Lima, compared to the 62,000 plants pulled there in the 1980s. They also pull from the primary four counties -- Missoula, Silver Bow, Park and Beaverhead -- and small infestations in Gallatin County near West Yellowstone. They scout all of the areas where dyer's woad was found historically.
The work since 1999 can be viewed through either end of binoculars: 6,000 plants is a huge number to pull by hand, and 6,000 plants is a small number compared to what the problem could be in the state if the work hadn't been done. And 6,000 plants is a huge number when they can produce a trillion seeds in just a few years.
"At larger sites, we are pulling and occasionally using herbicides to spray. We pull about 6,000 plants throughout the state each year," Pokorny said.
The weed-pull approach "wouldn't work for all weeds," Pokorny says. "While you can be effective pulling tap-rooted plants like dyer's woad and spotted knapweed, some invasive plants like Russian knapweed spread primarily by suckering roots and would just increase if you pulled only part of them. Dyer's woad produces hundreds of seeds on every plant, so when we pull them early in the growing season, we decrease the number of seeds produced and the number of plants the following year. The persistence of the dyer's woad project has prevented the weed from becoming a major problem in Montana."
Monica Pokorny mpokorny@montana.edu
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