Getting rid of cheatgrass (Bromus tectorum) requires combining multiple tactics because no single method kills this invasive annual grass permanently. The most effective current approach pairs a long-lasting herbicide with revegetation of native perennial grasses, which can suppress cheatgrass for years once established. But the details matter enormously: timing, herbicide choice, and what you plant afterward can mean the difference between a multi-year reprieve and a wasted season.
Why Cheatgrass Is So Hard to Eliminate
Cheatgrass thrives because it exploits a timing gap that most native plants leave open. It germinates in fall or very early spring, grabs soil moisture and nitrogen before native perennials wake up, sets seed by late spring, and dies. That early start gives it a decisive competitive edge. Research has shown that cheatgrass competes directly with native species for soil water and reduces their productivity, and these effects persist even a decade or more after a fire clears the landscape.1PubMed. Soil water exploitation after fire: competition between Bromus tectorum (cheatgrass) and two native species
Then there is the fire problem. Cheatgrass dries out into a continuous layer of fine fuel every summer, creating conditions for large, fast-moving wildfires that kill native shrubs like sagebrush. After the fire, cheatgrass recolonizes faster than anything else, which sets the stage for another fire a few years later. This grass-fire cycle has become the defining ecological crisis across the sagebrush steppe of the western United States, where the federal government has committed major resources to slowing the damage.2Conservation Science and Practice. Protecting restoration investments from the cheatgrass‐fire cycle in sagebrush steppe Linear fuel breaks are being installed across the region to moderate fire behavior, but those are containment strategies, not cheatgrass elimination.3Fire Ecology. Vegetation, fuels, and fire-behavior responses to linear fuel-break treatments in and around burned sagebrush steppe
The seed bank complicates things further. Cheatgrass seeds buried in soil lose viability over time, with significant declines after about a year, but some seeds remain viable for at least two years.4ScienceDirect (Journal of Arid Environments). Soil seed bank longevity of the exotic annual grass Bromus rubens in the Mojave Desert, USA That means even if you prevent all new seed production for one season, the buried seeds can repopulate the site the following year. Any control effort needs to last at least two to three years to exhaust the seed bank.
Herbicides That Actually Work
Two herbicides dominate the cheatgrass conversation: imazapic and indaziflam. They are not interchangeable, and the difference between them is large enough to matter for anyone choosing a strategy.
Imazapic was the standard for years and is still widely used, especially on rangeland. It reduces cheatgrass, but results are often incomplete and short-lived. In one Colorado field experiment, a fall application at a high rate cut cheatgrass by about two-thirds, but it also hammered native forbs, reducing them by a similar amount.5Natural Areas Journal. Effect of Imazapic on Cheatgrass and Native Plants in Wyoming Big Sagebrush Restoration for Gunnison Sage-grouse That collateral damage to native plants is a real limitation, particularly if you are trying to restore habitat for wildlife. The control it provides also tends to fade within a year or two.
Indaziflam has changed the calculus. This newer herbicide blocks a process specific to germinating seedlings, so it kills cheatgrass seeds as they sprout without harming established perennial plants whose root systems are already developed. In side-by-side comparisons, indaziflam provided roughly 84 to 99 percent control of cheatgrass two years after a single application, compared with about 36 percent for imazapic.6PubMed. Indaziflam: a new cellulose-biosynthesis-inhibiting herbicide provides long-term control of invasive winter annual grasses Even more striking, a single application maintained 70 to 98 percent cheatgrass control for up to eight growing seasons in Colorado shrub-steppe, and that suppression allowed native species to increase in diversity over time.7Restoration Ecology. Indaziflam for Cheatgrass (Bromus tectorum) control increased native species richness for up to 8 years in Colorado Front Range (United States) shrub‐steppe
The longevity of indaziflam is partly a puzzle. Soil residues become hard to detect after about two years, yet the herbicide continues to suppress cheatgrass into a fourth and fifth year. Researchers believe this happens because indaziflam coats seeds sitting on the soil surface and trapped in dead plant canopies, essentially poisoning the seed bank at the source rather than relying solely on soil concentration.8Weed Science. Indaziflam and imazapic applications to jointed goatgrass (Aegilops cylindrica) spikelets and cheatgrass (Bromus tectorum) seeds inhibits plant establishment
An important advantage of indaziflam over imazapic is its gentleness on non-target vegetation. In sagebrush steppe burned by wildfire, helicopter-sprayed indaziflam produced no reductions in cover for any native vegetation type, including biological soil crusts. In some cases, native perennial grasses actually increased in cover after treatment, presumably because removing cheatgrass freed up water and nutrients.9U.S. Geological Survey. Patchy response of cheatgrass and nontarget vegetation to indaziflam and imazapic applied after wildfire in sagebrush steppe
Targeted Grazing to Cut Seed Production
Timing livestock grazing to hit cheatgrass during its vulnerable growth window is a lower-tech alternative or complement to herbicides. The concept is straightforward: if cattle or sheep eat cheatgrass before it sets seed in late spring, far fewer seeds enter the soil bank for the following year.
Spring targeted grazing with cattle has been shown to reduce cheatgrass seed production by 30 to 77 percent compared to pastures where grazing started later in the season.10Rangeland Ecology & Management. Using Targeted Grazing to Close the Phenological Niche Exploited by Invasive Annual Bromes Cattle do prefer native grasses over cheatgrass when given a choice, so managers need to time the grazing early enough that cheatgrass is the greenest option on the landscape. Simple phenological cues, like watching when cheatgrass enters its boot stage, can predict when cattle will eat the most of it.
Combining grazing with herbicides appears to be more effective than either alone. In a study using sheep grazing integrated with fall-applied imazapic or rimsulfuron, cheatgrass cover dropped from around 26 to 33 percent down to 14 to 16 percent, a larger reduction than herbicides alone achieved without grazing.11Agronomy. Integrated Management of Cheatgrass (Bromus tectorum) with Sheep Grazing and Herbicide On its own, grazing reduces seed production but does not kill existing plants or affect the buried seed bank, so it is best understood as a suppression tool rather than an elimination method.
Bioherbicides Have Been Disappointing
For years, a commercially available product based on the bacterium Pseudomonas fluorescens strain D7 was marketed as a biological control for cheatgrass. The idea was appealing: apply a naturally occurring soil bacterium that produces a toxin inhibiting cheatgrass root growth, and let it establish itself to provide lasting suppression. Lab tests were encouraging, showing that D7 could selectively suppress cheatgrass in controlled settings.12Weed Technology. Inhibition of Downy Brome (Bromus tectorum) Root Growth by a Phytotoxin from Pseudomonas fluorescens Strain D7
Field results told a different story. When the D7 strain and a related strain called ACK55 were tested across multiple rangeland sites, neither provided reliable cheatgrass control under real-world conditions.13Rangeland Ecology & Management. Weed-Suppressive Bacteria Fail to Control Bromus tectorum Under Field Conditions Soil microbiome analysis suggests the bacterium simply fails to establish a lasting presence in the soil, which undermines the whole premise of a one-time application providing ongoing control.14PubMed Central. Soil microbiome analysis supports claims of ineffectiveness of Pseudomonas fluorescens D7 as a biocontrol agent of Bromus tectorum If you see D7-based products still being sold, the evidence suggests saving your money.
A Natural Seed Bank Killer
While the bacterial approach has flopped, a naturally occurring fungus offers more promise. Pyrenophora semeniperda is a pathogen that attacks cheatgrass seeds in the soil, causing high mortality in seed banks.15Rangeland Ecology & Management. Fire Effects on the Cheatgrass Seed Bank Pathogen Pyrenophora semeniperda The fungus is particularly deadly to dormant seeds, which cannot germinate fast enough to escape infection. In laboratory conditions, all dormant seeds exposed to the fungus at moderate temperatures were killed.16Seed Science Research. Environmental factors influencing Pyrenophora semeniperda-caused seed mortality in Bromus tectorum
Under field conditions, the impact varies with climate. Populations of cheatgrass in drier habitats sustained roughly 50 times more seed death from the fungus than populations in wetter areas, because seeds in dry soil germinate more slowly and are exposed to the pathogen longer. Older seeds left over from previous years experienced about 30 percent more mortality than fresh seeds.17PubMed Central. A Race for survival: can Bromus tectorum seeds escape Pyrenophora semeniperda-caused mortality by germinating quickly? This fungus is not yet a practical off-the-shelf product the way the bacterial bioherbicide was, but it represents one of the more plausible biological control angles under active research. Its effectiveness in arid sites, where cheatgrass does some of its worst damage, is encouraging.
Revegetation Is the Endgame
Every cheatgrass control method, whether chemical, mechanical, or biological, buys time. The clock starts running again as soon as the treatment wears off unless something else fills the space. That something is native perennial grasses, and establishing them is the single most important step for long-term prevention.
Perennial bunchgrasses suppress cheatgrass through a combination of mechanisms. Their root systems physically occupy the soil, they deplete nitrogen that cheatgrass depends on, and they interfere with the nitrogen cycle in ways that starve cheatgrass of the nutrient form it needs most. In controlled experiments, cheatgrass growing just ten centimeters from established perennial grasses lost nearly all its aboveground biomass, a 98 percent average reduction. Cheatgrass planted that close to established crested wheatgrass died within 38 days.18Rangeland Ecology & Management. Suppression of Cheatgrass by Perennial Bunchgrasses
Bluebunch wheatgrass, a widespread native of the sagebrush steppe, has shown especially strong competitive ability against cheatgrass across a range of conditions. Even under warmer, drier scenarios and elevated carbon dioxide levels, established bluebunch wheatgrass suppressed cheatgrass. The combination of dry conditions and elevated CO₂ actually enhanced the native grass’s competitive edge.19PubMed Central. Competition between cheatgrass and bluebunch wheatgrass is altered by temperature, resource availability, and atmospheric CO(2) concentration This is one of the rare pieces of good news in the cheatgrass story: under projected future climate conditions, well-established native grasses may actually become better, not worse, at keeping cheatgrass out.
The caveat is that perennial stands need to remain healthy. Long-term monitoring of sites where crested wheatgrass was originally planted to stabilize degraded land showed that after roughly 20 years, the wheatgrass stands degraded and cheatgrass invaded, even in communities that had been impervious to invasion just a decade earlier.20Native Plants Journal. Roughing up smooth brome and dethroning crested wheatgrass with native plants: dominant to subordinate on Utah rangeland A diverse mix of native species is more resilient over the long run than a monoculture planting.
Starving Cheatgrass by Manipulating Soil Nitrogen
Cheatgrass is a nitrogen hog. Disturbed soils, burned landscapes, and areas with disrupted biological soil crusts tend to have elevated available nitrogen, which gives cheatgrass exactly what it needs. One approach to tipping the balance involves adding a cheap carbon source, like sawdust or sucrose, to the soil. Soil microbes use the carbon as fuel and lock up nitrogen in the process, making it temporarily unavailable to plants. A meta-analysis found that carbon addition significantly decreased non-native weed abundance overall without significantly affecting native plants.21Journal of Applied Ecology. Efficacy of labile carbon addition to reduce fast‐growing, invasive non‐native plants: A review and meta‐analysis
In greenhouse trials specifically targeting cheatgrass, sucrose addition to previously invaded soil reduced cheatgrass aboveground growth by nearly 70-fold in the first growth cycle.22Applied and Environmental Soil Science. Plant-Soil Relationships of Bromus tectorum L.: Interactions among Labile Carbon Additions, Soil Invasion Status, and Fertilizer That dramatic effect occurred in soil that had already been altered by cheatgrass invasion. In soil that had never been invaded, the response was much smaller, which makes sense: uninvaded soil likely has lower baseline nitrogen availability. For landowners dealing with heavily invaded sites, carbon amendments are inexpensive and could be paired with herbicide treatment and seeding to create less hospitable conditions for cheatgrass regrowth.
What Prescribed Fire Can and Cannot Do
Burning cheatgrass sounds intuitive but is trickier than it appears. Timing a prescribed burn to coincide with seed maturation, when the seeds are theoretically most vulnerable, turns out not to work well because sparse fuel loads at that time of year generate fires too cool to kill the seed bank. Research using structural equation modeling found that postfire cheatgrass dominance was most strongly controlled by the size of the prefire seed bank, along with soil moisture, fire intensity, soil nitrogen, and sunlight exposure. Longer intervals between fires allow more surface fuel to accumulate, which produces hotter fires capable of killing a greater fraction of the seed bank.23International Journal of Wildland Fire. Impact of prescribed fire and other factors on cheatgrass persistence in a Sierra Nevada ponderosa pine forest
The practical implication is counterintuitive: less frequent burning may actually suppress cheatgrass more effectively than frequent burning, because the fires that result are hotter. But using fire as a standalone cheatgrass tool is unreliable. In most contexts, fire is part of the problem, not the solution, and any prescribed burn on cheatgrass-invaded land needs immediate follow-up with seeding and possibly herbicide to prevent reinvasion.
Climate Change Will Reshape the Map
The future extent of cheatgrass invasion depends heavily on precipitation patterns. Regional modeling has shown that decreased precipitation, particularly in summer, could expand suitable cheatgrass habitat by up to 45 percent, elevating invasion risk across parts of Montana, Wyoming, Utah, and Colorado. Conversely, increased precipitation could shrink suitable habitat by as much as 70 percent.24Global Change Biology. Regional analysis of impacts of climate change on cheatgrass invasion shows potential risk and opportunity This means the cheatgrass problem is not static. Areas that are marginal for cheatgrass today could become heavily invaded in coming decades if their climate dries out, while currently invaded areas that get wetter might see natural relief.
Cheatgrass also shows signs of adapting to new environments. At invasion edges in western Nevada, populations displayed high genetic diversity, and plants at higher elevations germinated more slowly and had lower survival rates than lowland populations, but surviving individuals achieved similar size and reproductive output. The occasional presence of outcrossing in these edge populations, unusual for a predominantly self-pollinating species, hints that cheatgrass may be generating genetic novelty that could help it colonize currently marginal territory.
The Cost of Inaction
Doing nothing about cheatgrass is expensive. Between 2014 and 2018, the Bureau of Land Management spent about $21 million suppressing just 11 wildfires in the Great Basin, with an additional $51 million for post-fire stabilization and rehabilitation. Fuel treatments, including targeted grazing, reduced fire containment costs by roughly 23 percent in one Utah comparison. If fire return intervals could be restored from the current cheatgrass-driven cycle of about 5 years back to a natural interval of 60 to 110 years, the projected savings could reach $180 million over a decade.25ScienceDirect (Journal of Arid Environments). Ranch Economics of Using Targeted Grazing to Create Wildfire Fuel Breaks on Public Land
Putting It All Together in Practice
For a landowner or land manager staring at a field of cheatgrass, the research points toward a sequenced approach rather than any single silver bullet. The first step is reducing the standing cheatgrass population. For sites where native perennials are still present, indaziflam is the strongest herbicide option because it suppresses cheatgrass germination for years without damaging established plants. For sites where you also need to knock back mature cheatgrass plants, combining indaziflam with imazapic provides both pre-emergent and post-emergent control, though imazapic’s collateral damage to native forbs is a real tradeoff to weigh.
Targeted grazing in spring can complement herbicide treatment or serve as a standalone suppression tool where chemical application is impractical or unwanted. The key is getting livestock on the cheatgrass before it heads out and drops seed, typically in late April to May depending on elevation and latitude.
Regardless of control method, the follow-through is revegetation. Seeding a diverse mix of native perennial grasses and shrubs adapted to local conditions creates the long-term competitive barrier that keeps cheatgrass from simply returning when the herbicide wears off. Bluebunch wheatgrass, basin wildrye, and other deep-rooted natives are strong candidates depending on your region. On heavily degraded soils, adding a carbon source like sawdust to temporarily immobilize nitrogen can buy native seedlings additional breathing room during establishment.
Skip the bacterial bioherbicide products. The field evidence does not support their efficacy. And think carefully before using prescribed fire on cheatgrass-invaded land without an immediate revegetation plan, since fire often accelerates cheatgrass dominance rather than curbing it.