Steamboat Springs Some of the flowers coloring roadsides and covering the hillsides do not belong there. Several species of weeds were accidentally imported from overseas and are destroying Routt County's native plants.
The whitetop flower is one such weed. It is a noxious, aggressive non-native species that invades pastures and meadows, displacing grasses and other forage plants valuable for wildlife and livestock.
Under Colorado law, landowners are required to control county-designated noxious weed species on their own land. Routt County Weed Control has designated eight species landowners are required to control: whitetop, leafy spurge, meadow knapweed, diffuse knapweed, Russian knapweed, spotted knapweed, Dalmatian toadflax and yellow toadflax.
Because of the abundance of these plants, the best way to control them is for landowners to self-police their property, Routt County Weed Control Supervisor Matt Custer said.
The Colorado State University Cooperative Extension Service is available to help identify the plants.
As a preventative measure, the Weed Control Department recommends removing seedlings because the newly established plants can usually be pulled without leaving root fragments in the ground. Ranchers can prevent weeds by simply keeping pastures healthy, using weed-free hay and cleaning equipment that has been used in infested areas.
It is also recommended that weeded areas be replanted with grass or other plants to discourage reinfestation.
Biological controls are not available for most of the weeds, but the herbicides "Escort" and "Plateau" are both effective. On a limited first-come, first-serve basis, the CSU Cooperative Extension Service will assist landowners in controlling weeds for $40 per hour plus the cost of herbicide.
Using a herbicide such as Roundup is not recommended because it is non-selective, meaning it can kill other plants that might out-compete noxious seedlings.