Last year’s drought in the Southeast showed many cattle producers that summer is a critical time in a cow-calf operation, says Gary Bates, Tennessee Extension forage specialist in Southeast Farm Press. And late April and May is the time to start working on your summer forage production. If you wait until summer, you’ll have waited too long because you can’t depend on tall fescue/orchardgrass pastures to provide much forage during July and August.

Bates suggests producers start thinking about planting a few acres of grass that will provide summer production. Generically called warm-season grasses, most of these grasses were developed in the tropical and subtropical regions of the world, and they have several characteristics that give them an advantage over cool-season grasses during the summer.

Warm-season grasses can produce energy through photosynthesis faster, which allows them to use more of the sunlight that falls on their leaves. They use water more efficiently, plus they have deeper root systems than cool-season grasses. In addition, warm-season grasses’ optimum temperature is about 90° F, while cool-season grasses perform best at about 70° F.

Most producers should think about planting a portion of their acreage to some type of warm-season forage, Bates says. While they won’t eliminate all drought-associated problems, warm-season forage can help mitigate some of the problems.

Here’s a quick primer on warm-season grasses:

  • Bermudagrass is a perennial grass that grows and spreads by above-ground stems known as stolons. A good hay or grazing forage, it’s very tolerant of close, continuous grazing. Some varieties can be planted from seed, while others don’t produce viable seed and have to be transplanted from live, vegetative material from another stand.

    Cold tolerance is a major consideration when selecting a variety, as winter-kill can cause severe stand loss in bermudagrass. Hybrids are highly responsive to fertilizer and can produce high-quality forage if harvested at early stage of maturity. Bermudagrass should be harvested every four weeks.

  • Warm-season perennial bunch grasses include big bluestem, little bluestem, indiangrass, eastern gamagrass and switchgrass. These forages produce high-quality forage early in the season, but quality drops rapidly as plants mature, just as with any of the other warm-season grasses. Seedling vigor is very low in these species, so weed competition can be a problem with establishment. Expect two years to establish a stand.

    Rotational grazing is essential for stand maintenance, so don’t graze below 8 in. If grazed too close, plants will weaken and stands will thin. Because of their sensitivity to close grazing or clipping, these plants are easier to use for hay, but can be utilized with grazing cattle.

  • Crabgrass is an annual grass selected for higher yield from native crabgrass populations in Oklahoma. Oklahoma research shows excellent yield and animal performance, while Tennessee experience indicates it can make an excellent summer pasture for stocker animals.

    Because it’s an annual, allowing plants to produce seed for the next year’s stand is necessary. No info is available to determine how successful natural reseeding of crabgrass will be due to the abundance of native crabgrass seed in Tennessee. There are two varieties currently available – “Red River” and “Quick-N-Big.”

  • Sorghum x sudangrass hybrid and pearl millet are both annuals. Relatively tall growing, they can be quite productive with timely summer rains. Sorghum x sudangrass hybrids can tolerate a cooler soil temperature, so they can be planted earlier than pearl millet. Sorghum x sudangrass hybrids release prussic acid (cyanide) after a frost, so they can’t be grazed as long as pearl millet. If there’s a potential for even a light frost, don’t graze a sorghum x sudangrass hybrid; only cut it for hay, which will allow time for the prussic acid to break down.

  • Teff grass, originally from West Africa, is a summer annual that should be considered along the lines of sorghum x sudangrass hybrids. With a little finer stem than the hybrids, it should be a little higher in forage quality, though yields may not be quite as high as with sorghum x sudangrass hybrids. Because the root system is shallow early in the season, care must be taken with grazing management; it may be better to take the first cutting off as hay.
While warm-season grasses can provide forage when tall fescue pastures are unproductive, their growing season is shorter compared to tall fescue, and there’s considerably more risk with them. If you decide to try one, be reasonable in the amount of land and resources you commit.

Tall fescue should remain the primary forage. A good rule of thumb is to have 70% of your acreage in cool-season grasses like tall fescue; 30% can be sown to a warm-season grass, with the goal to provide grazing during late June through early September.
-- Gary Bates, Tennessee Extension forage specialist