Species of grass that grow in cool weather often are referred to as cool-season grasses, while species that grow in warm weather are called warm-season grasses.

As grasses mature, digestible energy decreases, so young growth is more nutritious and palatable. That means range managers would expect a pasture with a balanced mixture of cool- and warm-season grasses to provide a more abundant and nutritious forage for livestock throughout the grazing season than a pasture dominated by just one group.

“Range monitoring procedures can help identify the balance of warm- and cool-season grasses in a pasture,” says Chuck Lura, rangeland specialist at the North Dakota State University Central Grasslands Research Extension Center near Streeter. “Producers may then adjust their management to provide more abundant and nutritious forage for their livestock.”

Cool-season grasses grow during the early and cool part of the growing season, but grow very little during the warmer days of summer, and may grow again during the cool days of autumn. Common cool-season species include the needlegrasses and wheatgrasses, prairie junegrass, Indian ricegrass, Kentucky bluegrass and brome.

Warm-season grasses are just the opposite. They grow very little during the cool days of spring and fall, but grow well during the warmer parts of summer when the cool-season species often are stressed. Common warm-season grasses include blue grama, big and little bluestem, switchgrass and prairie sandreed.

“Occasionally it is said that cool-season grasses are more nutritious than warm-season grasses,” Lura says. “That is true, but only if the comparison is made when the plants are at the same developmental stage. But because cool- and warm-season grasses grow at different times of the growing season, the comparison is not realistic.”

The Central Grasslands Research Extension Center has established a program to assist producers in implementing and maintaining range monitoring procedures. This effort is made possible through funding from NDSU, the North Dakota Natural Resources Trust and Ducks Unlimited.

To learn more about rangeland monitoring, contact Lura at (701) 424-3606 or chuck.lura@msub.nodak.edu. More information on warm- and cool-season grasses is available in NDSU Extension Service publication EB-69, “Selected North Dakota and Minnesota Range Plants.” It’s available through the NDSU Distribution Center at (701) 231-7882 or NDSU.DistributionCenter@ndsu.edu.

NDSU Agriculture Communication