One key to combating noxious weeds is knowing where they are, how quickly they've spread and which treatments are successful.
A group of volunteers, as well as officials from the city and U.S. Forest Service, hiked Spring Creek Trail on Thursday to look for and map toadflax.
The "weed warriors" found the two types of toadflax -- yellow and dalmatian -- during the hike, said Craig Robinson, open space coordinator for the city of Steamboat Springs.
"It's a very pesky, hardy weed that's hard to get rid of," Robinson said.
When the volunteers found a group of noxious weeds, they took the GPS coordinates. That information will be used to help measure the extent of the infestation.
Going back year after year allows the group to determine whether methods of controlling weeds -- from using herbicides to weed-eating bugs -- are working. Also, after the weeds are mapped, they can be destroyed by herbicide treatments and other methods.
The hike was one in a series of seven summertime hikes throughout the county organized through the Routt Invasive Plant Posse. Other sites that have been hiked include Emerald Mountain; the Mad Creek, Hot Springs and Red Dirt trails; and Lynx Pass.
Depending on the hike, volunteers may spread out and hike different trails or bushwhack along banks of a river, always keeping an eye out for weeds.
Volunteers for the Spring Creek hike began at the top of the trail and hiked down together. Having a group of people ensures the pesky yellow weeds aren't missed, Robinson said.
"The more eyes the better," he said.
Insects that kill toadflax have been released in the past several years along Spring Creek Trail, said C.J. Mucklow, Routt County Agricultural Extension agent.
"We are really hoping they're going to work," Mucklow said.
Toadflax doesn't always respond to a herbicide. But when the weed is weakened by insects first, the herbicide is more likely to work.
It's best to use more than one tool to manage noxious weeds successfully, Mucklow said.
"The more ways you can stress the plant, the more success you have," he said.
Insects have been released to combat different noxious weeds throughout the county. The main weeds targeted with insects have been musk thistle, leafy spurge and toadflax. Some insects eat the weed's roots, and others eat seeds.
Yellow toadflax grows from 8 inches to 2 feet tall, and Dalmatian toadflax grows from 2 to 4 feet tall. Both have snapdragon-shaped flowers that are bright yellow with orange centers.