Weed guru renews attack on noxious weeds in county
SUMMIT COUNTY – As firefighters from around the nation help combat Colorado’s wildfires, Paul Schreiner is fighting a biological battle of his own.
But instead of using water, the county’s weed control coordinator uses herbicides; instead of shovels, he uses his hands. He also depends on the eyes of citizens to let him know when they’ve spotted a new swath of musk thistle, houndstongue, knapweed or any of the other 20 or so noxious weeds that have invaded Summit County.
“Some people say, “Well, they’re prettier or showier than the natives,” he said on a recent weed walk. “But if we lose our natives, we’ve lost important genetic material.”
Noxious weeds are those plants that have moved – on the wind, in the hooves of animals or feet of hikers – into an area they’ve never been seen before. They often take over, usually because they have no natural predators to keep their spread at bay. Once they take root, they are difficult to eliminate. Additionally, they force out native plants.
In many parts of the country, including Colorado, noxious weeds have taken over thousands of acres of agricultural land, leaving large swaths of single-culture plants in their stead.
Schreiner said he is often asked if the noxious weeds’ invasions aren’t just a form of evolution, with new species moving in and old ones moving out.
“What sets the weeds apart is the pace at which they move in,” Schreiner said. “That’s no more evolution than taking the Ebola virus and bringing it here and calling it evolution.”
The flowers many of the weeds sprout may be showy and colorful, but they’re often harmful – even deadly – to people and animals.
According to Schreiner, an estimated 88,000 acres of land in the Flat Top Wilderness have been inundated by yellow toadflax. The flower’s seeds contain cyanide, and elk in the area might be affected in years to come as they graze on the weed.
“The seed companies said “Plant it and it will grow,'” Schreiner said. “And they were right.”
Eliminating it is further exacerbated by the fact a quarter-inch-long root left behind from weeding can grow into a new plant. Additionally, the plant loves fire, thrives in drought conditions, and herbicides that kill it kill neighboring trees.
False chamomile – the so-called “crazy daisy” so prolific along Summit County’s roadways and bike paths – blisters the mouths of animals that eat it. Toxins in houndstongue, which is growing in the north end of the county, collects in horses’ livers, causing them to lose weight. Knapweed contains a toxin that makes it difficult for horses to swallow, and can result in their death.
“If we end up with a monoculture, we’ll lose the insects,” Schreiner said. “The birds have nothing to eat, so they leave and the herbivores follow. If that happens, it will spell doom for the native population.”
Schreiner has implemented a variety of methods to rid areas of the noxious weeds, including applying herbicides, revegetating areas with native grasses, hosting “weed-pull” events and educational tours, using insects to curb the growth and goats to eat weeds in areas inaccessible to vehicles or that feature delicate ecosystems. The county has created an “Adopt a Bike Path, Trail or Open Space Parcel” through which volunteers monitor, among other things, new populations of noxious weeds. And Summit County’s towns are in the process of creating an intergovernmental agreement to develop noxious weed programs.
A herd of several hundred goats was brought to Summit County last summer, when they freely grazed on weeds along the Old Dillon Reservoir along the Dam Road, wetland areas near the high school in Frisco, at the Blue River inlet at Farmer’s Korner and near the Kingdom Park ballfields in Breckenridge. The animals are scheduled to revisit the areas July 15.
Despite all his efforts, however, Schreiner knows it’s almost impossible to eradicate the weeds completely.
Some lie dormant for years – musk thistle seeds can survive for 20 years. Others thrive in drought conditions and others extend roots up to 20 feet in the ground, making it virtually impossible to dig them out. Pulling up one toadflax plant merely prompts the weed to regrow twice as many new shoots.
One home in Eagle County was built in an area thick with Russian knapweed and Canada thistle, Schreiner said. After the home was erected, the weeds forced their way up through the crawl space, into floor joists and into the house. The homeowners noticed it when they found a bubble in their carpet – the plant itself – two years later.
Schreiner recommended people learn what noxious weeds in Summit County look like and notify his office to eradicate them. Of particularly importance is the lime-green leafy spurge, of which there has been at least one siting. The weed has an extensive sprouting root system and is one of the most serious noxious weed threats in Colorado.
Jane Stebbins can be reached at 668-3998 ext. 228 or firstname.lastname@example.org.
The Bad Seeds
Leafy spurge, Russian and spotted knapweed, yellow and
dalmatian toadflax, houndstongue and musk, plumeless and Canada thistles have already infested more than 88,000 acres in the White River National Forest. Those weeds are spreading at a rate of about 15 percent a year.
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