Destructive ventenata — arguably worse than cheatgrass — sweeps west across Wyoming

MEETEETSE RIM—Josh Shorb’s internal dialog upon learning that the destructive nonnative grass ventenata was found growing along the highway shoulder south of Cody spanned four letters and one syllable.

Because his gut reaction needn’t see print, the Park County Weed and Pest District supervisor pondered a more poignant way of describing his thoughts. 

“How do I say this?” Shorb said. “I was dejected, but not surprised. Then it was just time to get to work.” 

Late Tuesday morning, Shorb was getting to work. He was standing near where his colleague, Jake Jarrett, found the African grass growing along a Highway 120 ditch between Cody and Meeteetse earlier in the summer. 

Shorb was overseeing an aerial mission to douse ventenata with a chemical that would kill it: Rejuvra. Make no mistake, he knew he wouldn’t get it all, even though his contracted pilot was putting down the herbicide on 420 acres and well beyond the patches where the noxious grass was found. 

“This is day one,” Shorb said. “This is a plant where, if you turn your back for a few years, you’re going to be in trouble.” 

In the right conditions and the right place, ventenata can be even more destructive than cheatgrass, the most widespread annual invasive grass overtaking Wyoming. It has similar properties: Also called wiregrass, ventenata germinates in the fall, overwinters and cures out into tinder by summer. It’s even less palatable to livestock and wildlife, providing almost no nutrition to foraging critters. 

But until now, ventenata was more confined to eastern Wyoming. It showed up in North America in the early 1950s and Sheridan County in 1997, but distribution maps show it has been most widespread in the Pacific Northwest and Idaho. 

Shorb was standing and talking at the first detection site in Wyoming west of the Bighorns. His counterparts at weed and pest districts around the Bighorn Basin and broader western Wyoming are now on high alert. 

Shorb guesses that ventenata seed was given an accidental ride into the area from Carbon County, Montana, which has a bunch of it. 

“Something got kicked out of a tire, like a piece of mud,” Shorb said. “Now here we go.” 

Heightening costs and declining resources will make responding more difficult. Envu-manufactured Rejuvra is already notoriously expensive — about $1,100 a gallon — but in 2026 the cost of spraying “has really gone up,” Shorb said. With fuel and herbicide costs on the rise, he’s now paying roughly $75 an acre. That means just on Tuesday, the Park County Weed and Pest District was looking at a $32,000 bill. 

While one-time grant money allocated by the Wyoming Legislature helps, other funding streams have suffered. Property tax-reliant weed and pest districts around Wyoming have taken a hit, and now the Bureau of Land Management is scaling back its own spending to spray cheatgrass — and now ventenata. In 2026, the BLM’s Wind River/Bighorn Basin Field Office invested a whopping $1.2 million on cheatgrass spraying in Park County alone. 

In 2027, however, Shorb’s bracing for vastly reduced assistance from the federal government. 

“The BLM, they still have some money for noxious weed control, but specifically for cheatgrass control, we’re told that they’re out,” Shorb said. “This is just a perfect storm of what we don’t need right now.”