Dogs that sniff out undesirable weeds are on the trail of Dyer's woad in Montana.
Pooches like Wibaux the Lab scramble up Montana mountains to catch the scent of the noxious weeds so they can be removed before they spread.
Once located, Wibaux circles the weed like a hunting dog on a dead duck and barks to alert her human companions that she has once again found a dread Dyer's, so named for the fact it was used by pioneers as a source of dye.
But the woad is now attacking pastures and rangelands of Montana with an attractive presence that hides its tendency to choke out more valuable vegetation.
With a "Good Dog!" for a job well done, weed-hunter Deb Tirmenstein hands the eager Wibaux a coveted treat.
Then she marks the location of the find on her GPS to return later with a spray to take out the undesirable plants.
It is a project which grew from Montana State University research that proves dogs are good weed finders. A goal of the Dyer's woad study is to eradicate it from Montana via dogs and their two-legged companions
Amber Burch, assistant wed coordinator for Beaverhead County and a coordinator of a statewide effort against woad, says the weed is native to Russia and was once used as a source of blue dye and medications.
The first recorded Montana sighting was in 1934, and it is classified as a Priority 1B Noxious Weed in the state, akin to being on the Most Wanted list from the FBI.
A single plant can grow four inches a week and produce 10,000 seeds, notes Burch. Roots can drill five feet into the ground. On top of the soil surface, they compete with native plants and can overrun pastures and wildlife habitat.