Herbicide treatments to control cheatgrass also need to be carefully planned.

Because cheatgrass and Japanese brome generally green up at least two weeks before most key forage species, some unique chemical-control opportunities exist. On rangeland, use of Roundup (glyphosate), Journey (imazapic plus glyphosate), or Plateau (imazapic) provide management options for cheatgrass infestations.

While cheatgrass is a prolific seed producer, seeds usually don't remain viable in the soil for more than 2-3 years. Thus, chemical control to prevent seed production in the spring reduces the number of seeds in the soil and provides long-term benefits.

On the Padlock Ranch, in areas where cheatgrass populations are exceptionally high and grazing management isn't working, a light application of Roundup in the spring is used.

“It helps reduce the competition from the annuals without harming native perennials,” Luse explains. “The application will set the perennials back depending on the amount of herbicide used, but they will come back.” He says 4-6 oz. of Roundup/acre works well without damaging nontarget species.

Consensus is that care should be taken to only apply Roundup when range grasses are dormant to avoid risk of injury to desirable plant species. If perennial grasses have initiated new growth, Roundup at its lower recommended rate can be used, but some growth stunting of perennial grasses may occur.

Meanwhile, Journey provides pre- and postemergence control of cheatgrass, says Fabian Menalled, Montana State University weed specialist.

For best results, Journey should be applied in late summer or fall before cheatgrass seedlings emerge and prior to planting desirable species; don't use after newly seeded desirable species have begun to emerge.

“Spring applications of Journey can increase consistency in cheatgrass control,” Menalled explains. “However, these spring applications should be limited to areas without a large number of desirable plants.”

Plateau is a broad-spectrum herbicide that provides control of cheatgrass and allows desirable native grasses and forbs to reestablish after treatment. Menalled recommends late-summer or fall applications of Plateau, preemergent to germination for the most effective control of cheatgrass and other bromes.

“This invasive species, while always present, really became a problem after the drought years of the last decade,” Luse concludes. “Cheatgrass is a formidable competitor with our native grasses.”

Clint Peck is director of Beef Quality Assurance, Montana State University.