October 17, 2008

Do you have native summer pastures? Are they becoming overrun with cool-season plants?

Cheatgrass, downy brome, bluegrass, smooth brome and other cool-season plants have invaded many warm-season grass pastures and rangeland. This invasion shifts good grazing away from summer and toward springtime when most folks have plenty of pasture.

Cool-season grasses take over summer pastures relatively easily because they develop rapidly during fall and spring when native grass provides little competition. They use moisture and nutrients before warm-season plants have a chance to use them.

Fortunately, several tools can revitalize warm-season grasses and reduce pressure from annuals, brome, and bluegrass.

Hard grazing in late fall after a freeze and in early spring and prescribed spring burning will weaken brome and bluegrass when warm-season plants are dormant and unaffected. An even faster approach is to apply glyphosate herbicides like Roundup in late fall after a hard freeze when weedy cool-season grasses are still green but warm-season plants are dormant. This will kill or weaken the green and susceptible cool-season grasses but not affect dormant warm-season plants.

Recent weather has made this an ideal fall to use herbicides. Warm-season grasses will soon go dormant after a hard freeze and sufficient rainfall and daytime warmer temperatures are keeping cool-season grasses active.

By reducing competition this fall, warm-season plants will grow more vigorously next year and provide better summer pasture.

Bruce Anderson
Extension Forage Specialist