23rd Annual Gros Ventre River Spray Days 2022

Over three days, partners with the Jackson Hole Weed Management Association (JHWMA) collaborate on an invasive weed project across the Gros Ventre River corridor. 

“The goal is to contain and reduce the spotted knapweed infestation that is thought to have started on the Gros Ventre River in the 1970’s…without this amazing group coming together for this team effort, we would be losing critical wildlife habitat to these invaders”

Erika Edmiston, Supervisor at TCWP

Between July 19th and the 21st this year, various crews and individuals from Teton County Weed and Pest, Grand Teton National Park, and other organizations team up to mitigate the invasive weeds that negatively impact elk, moose, deer, bison, birds, and other animals in this area.

JHWMA - Backcountry Horseback Spraying Horse Train Image

The 1,200+ Acre Project Area

Each year approximately 50-100 acres of invasive plants are sprayed by plant management team members and volunteers who join the fight. As always, the three days of spraying are grueling but necessary work. Per usual, the end of July tends to be in the mid to upper 80s at the heat of the day. The spray days (albeit hot and long) offer a glimmer of hope. The hope that invasive plants throughout this corridor can be contained and mitigated—and that our wildlife have abundant native vegetation to eat. 

Plus, the three spray days build camaraderie among like minded citizens—people who understand the seriousness of invasive species and want our ecosystem to thrive. Although the crews typically break into separate groups to focus on specific areas, camaraderie is built during a shared lunch. Here, people who have never met can introduce themselves to others and learn more about different styles of management, work days, species control, herbicide application rates and techniques, and even each others’ hobbies.

The agencies, organizations, and businesses that have assisted with the project over the years include but are not limited to:

Fremont, Lincoln, Natrona, Park, and Teton County Weed and Pest Districts in Wyoming, Bonneville and Teton County Weed Districts in Idaho, Jackson Hole Fire/EMS, Boreal Property Management, Jackson Hole Property Services, Intermountain Aquatics, the Bridger-Teton, Custer Galatian, and Shoshone National Forests, the National Elk Refuge, Yellowstone and Grand Teton National Parks as well as the National Park Service – Northern Rockies Exotic Plant Management Team.  The Bureau of Land Management, Wyoming Department of State Lands, Jackson Hole Land Trust, Hanna Outfitting, Gros Ventre River Ranch, Jackson Hole Golf and Tennis, Teton Conservation District and the Rocky Mountain Elk Foundation.

The Main Target—Spotted Knapweed

Spotted knapweed
It is named for its black or dark-brown-spotted bracts

Although crews will target any invasive plant species in the project area, the main concern is spotted knapweed. Spotted Knapweed outcompetes native plants along the Gros Ventre River Corridor which can therefore decrease biodiversity in the area. In addition, it may “degrade soil and water resources by increasing erosion, surface runoff, and stream sedimentation.”

How Long Has Spotted Knapweed Been in the Gros Ventre River Corridor?

Although a definitive answer may never exist, here’s the known timeline:

  • 1974 – Spotted knapweed was mentioned at a Weed and Pest District Board Meeting
  • 1999 – JHWMA partners decided it was important to begin recording the presence of noxious weeds throughout Teton County.
  • 2000 – Crews from Grand Teton National Park, the Bridger Teton National Forest, Teton County Weed and Pest, and the National Elk Refuge began targeting spotted knapweed along the river corridor in the hopes of reducing and containing the infestation and keeping the infestation from spreading further east into the Gros Ventre area.
  • 2001 – Spotted knapweed was found between the Forest/Park boundary and Lower Slide Like on the Gros Ventre Road. 
  • 2008 –  Spotted knapweed was found at the Lower Slide Lake Campground
JHWMA - Gros Ventre River Spray Days Truck Coming up Road with Noxious Weeds image
We Need Spray Days!

Clearly, spotted knapweed spreads like wildfire in ecosystems like ours. Therefore, the Gros Ventre River Spray Days continue to be integral to the protection of wildlife habitat in Grand Teton National Park and the National Elk Refuge. 

The JHWMA Spray Days event is unique in that it pulls together groups from across western Wyoming. Without concerted efforts each year, our river corridors would continue to degrade without any hope in sight. Thankfully, the spray days are a step in the right direction.

If you have any questions about the project area, how to volunteer during spray days, or to learn more about JHWMA, visit www.jhwma.org