State pushes to combat invasive grasses

SHERIDAN (WNE) — Following the devastating fire season of 2024, invasive annual grass control became a priority throughout Wyoming to protect what grazing and wildlife forage remained and to help native species reestablish inside the fire scar.

Cheatgrass, ventanata and medusahead are IAGs that compete with native vegetation and can become dominant on the landscape. They hold little and short-term forage value for livestock and wildlife. 

If present before a fire, they provide a large fine fuel base that helps carry the fire. Subsequently, because they are annuals, they can respond and reinvade quickly after fire before the native plants get a chance to recover.

It is estimated that Wyoming is invested with more than 15.4 million acres of cheatgrass.

“Being proactive and treating IAGs before they burn can help prevent catastrophic fires in Wyoming,” said Garrett Falkenburg, president of the Wyoming Weed and Pest Council. “As we race this invasion across the state, we often need to treat pre- and post-fire to save the good vegetation from further invasion. The WWPC and Wyoming Wildlife and Natural Resource Trust work together to develop management plans for both scenarios.”

In 2025, Wyoming Weed and Pest Districts partnered with WWNRT to treat hundreds of thousands of acres of IAGs. The effort, which was undertaken by Gov. Mark Gordon, delivered nearly $50 million in legislatively allocated funds for on-the-ground projects to prevent the spread of IAGs while restoring resilient grass and rangelands.

The treatments used the herbicide Rejuvra (indaziflam) produced by Envu Environmental Sciences. Rejuvra is effective against IAGs by killing new plants as they germinate, while leaving perennial native species undamaged. In many cases, following the Rejuvra application, native species resurge because there is less competition for resources. This has been a game-changer for IAG control statewide.

This story was published on April 20, 2026.