Rangeland Restoration Depends on Control of Invasive Annual Grasses

Invasive winter annual grasses, like cheatgrass, medusahead and ventenata can be prolific seed producers. The seeds germinate in fall or winter and the invasive grasses grow rapidly in late winter and early spring, using up available soil moisture and nutrients while desirable perennial plants are still dormant.

Once these invasive annual grasses mature and set seed, the destructive cycle continues as the resulting seed can remain viable in the soil for three to five years. Left unchecked, these invasive grasses dominate the landscape, the desirable plants begin to disappear and fine fuel layers build to dangerous levels.

Seed Bank Depletion is the Key to Successful Restoration

For years, ranchers and land managers have attempted to restore rangeland infested with invasive annual grasses; however, few have been consistently successful. Although initial control can be found with existing management tools, rapid reinvasion from the soil seed bank often occurs, hindering restoration efforts.

Fortunately, Rejuvra^® herbicide from Envu is a new restoration tool that land managers can now use to target the invasive annual grass soil seed bank.

“Rejuvra herbicide has given us a tool to finally deplete the invasive annual grass seed bank. We’re achieving long-term control, resulting in landscape scale benefits including increased rangeland production, the release of desirable perennial plants, improved wildlife and pollinator habitat, and decreased fine fuels associated with wildfires,” said Dr. Derek Sebastian, Envu area sales manager.

Restore the Land and Protect Desirable Perennial Plants

Long-term control of invasive annual grasses helps to restore and protect rangeland, conservation reserve program (CRP) lands, natural areas such as parks and open spaces, wildlife management areas, recreational areas, fire rehabilitation areas, prairies and fire breaks. This includes sites that are grazed by livestock.

More than 100 replicated field trials throughout the western United States have documented that Rejuvra is a highly effective tool for controlling the major invasive annual grasses, including cheatgrass, Japanese brome, medusahead, ventenata, jointed goatgrass and bulbous bluegrass (bulblettes).

“We have been able to show that with Rejuvra, we are increasing rangeland production, and at the same time pollinator and wildlife habitat. In both research trials and operational treatments, the long-term control provided by Rejuvra has resulted in an increase in native species richness, the number of flowers per plant and increased growth and vigor in critical winter-range brush species like Mountain mahogany and antelope bitterbrush.

“This is really exciting because the tools used in the past have not provided consistent control or provided relatively short-term control,” said Dr. Sebastian. “Rejuvra is actually giving us the control we need to deplete the seed bank and also increase the productivity and the diversity in those areas.”

Sources:

Clark, S. “Using Herbicides to Restore Native Species and Improve Habitat on Rangelands and Wildlands.” Outlooks on Pest Management, 2020.

Koby, L.E., Prather, T.S., Quicke, H., Beuschlein, J. and Burke, I.C. “Management of Ventenata dubia in the Inland Pacific Northwest with indaziflam.” Invasive Plant Science Management, 2019.

Sebastian, D.J., Fleming, M.B., Patterson, E.L., Sebastian, J.R., and Nissen, S.J. “Indaziflam: A new cellulose-biosynthesis-inhibiting herbicide provides long-term control of invasive winter annual grasses.” Pest Management Science, 2017.

Sebastian, D.J., Nissen, S.J., Sebastian, J.R., and Beck, K.G. “Seed Bank Depletion: The Key to Long-Term Downy Brome (Bromus tectorum L.) Management. Rangeland Ecology & Management, 2017.

Seshadri, A. and Sauer, S. Bringing back glowering plants and pollinators through effective control of invasive winter annual grasses with Esplanade® herbicide. Boulder County Open Space Small Grant Report, 2018.