Landon Kuestersteffen’s flip flops crunched over the brown stems of diffuse knapweed that blanket a meadow just south of Foxglenn Park and the Coconino Humane Association.

Later this summer, the invasive plants will be sprayed with herbicide to knock them down so volunteers can get in and more easily hand pull them, Kuestersteffen said. It’s part of a two-year project to attack weeds that grow thick on this stretch of city-owned land near the Rio de Flag and the Flagstaff Urban Trail.

Though weed control isn’t the flashiest part of land management or open space projects, letting invasive and noxious species run rampant can ruin a stretch of land like this, crowding out native species and making an area impassable for people and uninhabitable for other creatures.

For years, the Flagstaff area had a group dedicated to tackling a range of invasive species, from colonies of yellow-flowered leafy spurge to groups of spindly diffuse knapweed. Then, for several years starting around 2013, that group dwindled and the work mostly fell by the wayside.

But now a handful of people are trying to revive the San Francisco Peaks Weed Management Area.

One at a Time

Knapweeds, an invasive species in northern Arizona, cover a meadow south of Foxglenn Park that will soon be treated with herbicides under a collaborative between the Flagstaff Arboretum and the city of Flagstaff. Both entities are trying to revive the San Francisco Peaks Weed Management Area, which was a longtime leader on weed projects in the area. 

Made up of a diverse group of agencies and nonprofits, the weed management group is one of several across the state. Weeds don’t know boundaries, so the group’s role is to unite different government and nonprofit agencies that have an interest in fighting weeds and help them work together and more efficiently use resources, said Kristin Haskins, the interim coordinator of the weed management area and director of research at The Arboretum.

“We’re serving as a unifying organization with a focus of weed treatment and weed education and getting people to work across boundaries,” she said.


Started in 1999, the group was once flourishing, with 30 people around the table at each meeting and tens of thousands of dollars in grant funding each year, said Scott Harger, who was a volunteer for about 10 years and then served as coordinator twice, for a total of about five years ending in 2013.

The group helped residents deal with nasty weed outbreaks after the Schultz Fire, bought tools for use on community weeding days and helped tackle scotch thistle, an invasive with purple flowers and spiny leaves and stems, in Picture Canyon, Harger and Haskins said.

Many people might not realize all the work that has been done, Harger said, but in many of Flagstaff's vacant lots, right-of-ways around the railroad tracks and school yards where the group unleashed weed-eating insects, the individual weed plants are about a quarter of the size they would have been and twice as far apart.

The work takes persistence. It takes 18 years to get rid of a colony of scotch thistle, Harger said.

“If you miss a year you start a new clock,” he said. That’s why the weed management group’s decline in recent years is particularly disappointing, he said.

As it starts to gain ground again, the group is starting small. Grant funding is paying for one intern, Kuestersteffen, to help get the organization off the ground and complete some administrative work. Members are looking at grant opportunities and ways they could pay for an official, dedicated coordinator.

An Invasion of Knapweeds

A large collection of knapweeds cover a meadow south of Foxglenn Park. Its one of many areas in Flagstaff that need extensive weed treatment. 

Though it has hit a lull, this management area group is unique in being one of the few in the state that hasn’t completely disbanded or merged with organizations that have a broader mission, said John Richardson with the state’s Department of Forestry and Fire Management.

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Haskins said there are lots of places that are getting overrun with nasty invasives where the group’s work is needed — medians along Interstate 40, an area near Woody Mountain Road that was once used as a dumping site and some lots along Butler Avenue, especially one across from Warner’s Nursery that feeds into the Rio de Flag drainage.

For his part, Harger has been eyeing an ever-growing colony of teasel, a tall prickly plant with spiny purple flower heads, that is overtaking a ditch on the north side of Huntington Drive. It’s growing closer and closer to the Rio de Flag and, if it isn’t treated, Harger said in four or five years he expects the teasel seeds to get carried down the rio and into the meadow where Kuestersteffen is trying to get rid of knapweed.

The weed colony is still small enough that it could be eradicated, but if not it will be a nightmare, he said.

Climate change presents another potential challenge, as it’s still hard to tell how it will affect plant communities — both invasive and native, said Sat Best, a member of the weed management area group and the former facilities manager at the Museum of Northern Arizona and its 200-acre property. Several invasive species, such as cheatgrass, do much better in the drier conditions, and coordination will be key to make sure native plants have a chance against invasives and a hotter, drier future, he said.


On forested lands just outside of Flagstaff, weed management has been a larger focus for the past five years as forest restoration programs like the Flagstaff Watershed Protection Project and the Four Forest Restoration Initiative ramp up, said Julia Camp, a wildlife biologist with the Forest Service's Flagstaff Ranger District who manages the rare plants and weeds program.

Weed management is a greater necessity because logging operations disturb ground and create more sunlight, creating prime conditions for invasives to spring up.

“The last thing we would want to do is try and restore the forest and then make it worse," said Mike Elson, the Flagstaff District ranger.

Mullein along FWPP road

Invasive mullein lines a logging road created at the base of the Dry Lake Hills for the Flagstaff Watershed Protection Project. 

Thanks to an influx of money connected to the tree thinning projects, the district has been able to fund a full-fledged weed management program with a program manager, on-the-ground crew leader and seasonal crews, which most other districts don’t have, Elson said.

While other forests in the country have “lost the battle” against weeds, the Coconino National Forest has fewer problem species to worry about, and on the Flagstaff Ranger District at least, staff have been able keep the worst weeds mostly under control, Elson said.

Crews are doing regular surveys of logging contract areas, including the logging roads that have recently been built at the base of the Dry Lake Hills and Mount Elden for FWPP, to make sure especially problematic species like diffuse knapweed aren’t getting out of control, Camp said. So far they haven’t found any big outbreaks, she said.

The fuzzy-leafed mullein that lines logging roads up there may be prolific now but should be overtaken by native plants in a few years, Elson said. Cheatgrass, too, isn’t outcompeting the native plants.

The restoration of natural forest conditions via tree thinning should also help give native species a leg up and as they gain ground they are their own best defense against weeds, Elson said.

Even so, Best, whose house borders the national forest, said he’s still worried about the cheatgrass, toadflax and mullein along the new logging road.

“There are a lot of places in the country where the plant community has been changed dramatically by invasive weeds and we don't want that to happen here,” he said.

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Emery Cowan can be reached at (928) 556-2250 or ecowan@azdailysun.com


Environment, Health and Science Reporter

Emery Cowan writes about science, health and the environment for the Arizona Daily Sun, covering everything from forest restoration to endangered species recovery efforts.

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