Teton County weed superintendent Amanda Williams, dwarfed by musk thistle. Her department receives more complaints about thistles than anything else.

Amanda Williams, the county’s weed superintendent, has a grudging kind of respect for the hardy invasives that have succeeded in Teton County. She describes noxious weed species as “impressively successive,” “sneaky,” and “ecological dogfighters.”

This is Williams’s fourth summer as the county’s weed superintendent. The 32-year-old Missourian guided whitewater and rock climbing while in college and knew she wanted to work outside, but didn’t realize until she got a job spraying weeds for Yellowstone National Park that she had stumbled upon a passion.

“Noxious” is an official designation that indicates a weed is detrimental to agriculture or the environment. Many weed species are problematic because they crowd out native species without offering forage for wildlife or livestock. Idaho state statute requires that counties employ superintendents to control noxious weeds on county properties and thoroughfares. Williams is also in charge of making sure that landowners police their own properties, and if a landowner fails to do so, he or she has to reimburse the county for doing control work.

The county receives the most complaints about the visible and obvious musk thistle, but Williams said that unfortunately unless the patch is especially dense or in a high priority area like near a highway or public land, the county can’t devote resources to it, since there is no chance of fully eradicating the species. The best return on investment, she added, is the discovery and quick eradication of newly arrived species.

Williams’s real concerns are the more pernicious species, such as spotted knapweed and yellow toadflax, which are a high priority for the county.

“It’s sneaky and difficult to get a handle on, and doesn’t respond as well to chemical control,” she said of knapweed, which travels around the valley in waterways, including irrigation ditches.

Recently Williams has found small patches of rush skeletonweed and dyer’s woad, both of which have the potential to spread and threaten native species.

While some noxious species are easy to identify, others, like hoary alyssum and whitetop, just seem like generic white-flowered weeds. That’s why Teton County offers free site visits and weed workshops. You can even take a photo or bring an uprooted plant to the office for identification.

“Be familiar with your property and contact the weed department if you see something out of place. I’d much rather get a ton of questions and ID requests than let a species establish itself,” Williams said.

One hot topic in eastern Idaho weed circles is flowering rush, an aquatic invasive that doesn’t respond to herbicides that can be used in waterways. Flowering rush has spread through the canals and rivers of the region and the only effective way to control it is by dredging the waterways to remove the vegetation. While it hasn’t yet been found in the valley, Williams said that flowering rush would like Teton River because it’s a slow moving body of water. The weed would choke the flow of the river and dredging the bed would disrupt other species as well.

“I think the risk of it arriving here is fairly low, but we would have to detect it as soon as possible,” she said.

The county weed department consists of one full-time, year-round employee and one seasonal worker. In the summer, Williams and her staff spend early mornings spraying and controlling weeds on county roads and properties before the wind picks up. Afternoons are devoted to site visits, enforcement, and other tasks.

The county sells some discounted herbicides that have been proven effective in the area, and also rents out backpack sprayers for $10, including the herbicide mix. Williams said her department would much prefer to work with landowners to control noxious weeds instead of writing tickets and doing enforcement work. Visit www.tetoncountyidaho.gov/weeds for more information on the county’s services.

For people with larger properties who are combating a single problematic species in hard-to-access terrain, there’s another possible answer: bio-control agents. The Nez Perce Bio-Control Center in northern Idaho has a carefully developed and tested suite of bio-control agents like mites, insects, and fungi that predate on specific weeds. The center’s agent releases are planned far in advance, so get in touch with Teton County now to pursue bio-control for next year.

Last summer’s abrupt, early cessation of precipitation meant a slow year for weeds, but Williams predicts that this summer (if it ever warms up) weeds will have a long seeding period. Right now is a good time to manage an infestation, because seeding hasn’t started yet.

Williams spends the winter writing grants, researching new species and control methods, and doing data entry. That’s also when she gets to focus on outreach, education, and collaboration with other weed superintendents in the region.

“The eastern Idaho superintendents work together really well,” she said. “Every superintendent has a unique perspective.”

Because Teton is a border county and a part of the Greater Yellowstone Ecosystem, Williams pays attention to the noxious weed lists of Montana and Wyoming and is a member of the Greater Yellowstone Area Terrestrial Invasive Species Committee. She works with other public agencies to inventory, manage, and prevent the spread of noxious weeds.

“We get together and talk about species,” she said. “It’s about being a good steward and a team player.”


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