Cheatgrass is considered one of the most significant invasive grasses worldwide, changing native plant communities, altering fire behavior, and impacting agricultural and rangeland systems.
Forecast coming for the 2027 season.
WHAT ARE PHENO FORECASTS?
Pheno Forecast maps predict key life cycle stages in invasive and pest species, to improve management efficacy. For invasive plant species, Pheno Forecasts are based on published growing degree day (GDD) thresholds for key points in species life cycles. These key points typically represent life cycle stages when management actions are most effective. For cheatgrass, we forecast flowering and senescence for the full calendar year.
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Sign up to be notified by email approximately two weeks and again six days ahead of key growing degree day thresholds for species of interest at your location
SPECIES BACKGROUND
Cheatgrass (Bromus tectorum) is native to southern Europe, northern Africa, and southwest Asia, but it has spread widely and is now present on every continent except Antarctica. Cheatgrass germinates early, grows quickly, and outcompetes native grasses and wildflowers. It has altered fire regimes by creating a continuous layer of fine, dry fuel that carries fire easily across the landscape. While cheatgrass can provide some early-season forage, its feed value declines quickly as plants mature and dry, reducing pasture productivity.
LEARN HOW TO OBSERVE PHENOLOGY OF CHEATGRASS
Our learning module walks you through how to identify cheatgrass, how to report its life cycle events, and why you should care.
FLOWERING AND SENESCENCE FORECAST
We forecast flowering and senescence based on growing degree day thresholds as well as soil moisture levels, which were shown to increase predictive accuracy for this life cycle event. The forecasts are available for the contiguous United States, except for those areas where the temperatures and soil moisture for the current year are expected to be either too extreme for cheatgrass to survive or develop. The forecasts can support ranchers in timing grazing after grasses have grown enough to provide good forage, but prior to unpalatable flowering and seeding stages. This practice reduces the development of new seeds and subsequent spread of the species. The forecast for senescence may also inform managers about when cheatgrass has dried sufficiently to become highly flammable, increasing wildfire risk. The forecast can help managers time fuel reduction measures. The forecasts also support the interpretation of satellite imagery of grassland green up. For more information on treatment guidance, visit USFS Fire Effects Information System (FEIS).
| Phenophase | GDD threshold | Base temp | Upper threshold | Start date | GDD method | Model origin | Source |
|---|---|---|---|---|---|---|---|
Flowering* | 782oF | 32oF | 95oF | Jan 1 | Single triangle | ID, WY, NE, UT, CO, AZ | DDRP and Barker and Coop 2026 |
Senescence | 1674oF | 32oF | 95oF | Jan 1 | Single triangle | ID, WY, NE, UT, CO, AZ | DDRP and Barker and Coop 2026 |
*The model forecasting flowering timing also incorporates the effects of 35-day antecedent soil moisture gradients on seedling/rosette development.
The development of this forecast was funded primarily by USDA NIFA AFRI TSAB Award #2022-68013-37138 to support agricultural biosecurity.
More information on map development and re-use policy.