Native Warm Season Grasses

Although it may be hard to imagine, Kentucky was once covered by about 3 million acres of native grasslands. The native grasses were critical in supporting the large and diverse wildlife populations present in pre-settlement days. However, with the arrival of Europeans came an intensification and modernization of agriculture that has now resulted in a landscape dominated by fescue. Research has shown that fescue provides very poor habitat for wildlife, and creates problems for livestock as well. Eradication of fescue* and restoration of native grasses is beneficial for both wildlife enthusiasts and farmers alike. Financial or other assistance for establishing native warm season grasses may be available; if interested, contact your local wildlife biologist for details.

Native warm season grasses (prairie cordgrass, eastern gamagrass, switchgrass, big & little bluestem, Indiangrass, side-oats grama) are bunch grasses, growing in clumps that provide excellent year-round cover for small game and nutritious (6-19% protein) forage for livestock while retaining enough bare ground to allow gamebird chicks to move freely in search of food. They are also summer grasses, actively growing when the soil temperature is above 65 degrees. They are an integral part of a diverse plant community whose wildflowers, legumes (lespedeza, partridge pea, etc.), and annual weeds provide abundant food, particularly for quail, and which in turn attract numerous insects important to young chicks as a source of protein in spring. Most species are fairly tall, growing to 5-8 feet in height; however, a couple of species (little bluestem and side-oats grama) are short, only growing to about knee or waist high.

Native grasses grow on a variety of sites. Little bluestem and side-oats grama need a well-drained or dry site. Big bluestem, Indiangrass, and gamagrass will grow on most any type of site, from wet to dry. Switchgrass will also grow on most any site; however, on wet sites, either Kanlow or Blackwell varieties should be used. Prairie cordgrass is also an option on wet sites; if interested, contact your local biologist for more details. Be advised, gamagrass seed has a thick coat that hinders germination. Although untreated gamagrass seed can be purchased at lesser cost, it will likely take longer to develop. For optimum results, you should use seed that has been treated to overcome this natural dormancy and increase germination the first year by either chemical (preferably) or refrigeration methods.

The various species of native grass also mature at slightly different times. Gamagrass and switchgrass mature in early summer (June), big bluestem matures in mid-summer (July), and Indiangrass matures in late summer (August). Generally speaking, if establishing them for use primarily as pasture/hay, it is best to plant several fields each containing 1-2 species of native grass, together with some lespedeza, so individual stands of grasses may be rotationally grazed or hayed as they become mature. However, if you want to optimize benefits to both wildlife and livestock, you may want to combine 3 or more of the grasses in the same stand to increase diversity. It is also worth noting that demand for the seed of these grasses has increased greatly in recent years, such that the potential for harvesting and re-selling seed has created an economic incentive for landowners to plant them.

Site Preparation

Native warm season grasses are usually planted in spring (May-June). Preliminary work such as burning*, haying/raking, mowing, or grazing may be necessary to eradicate thick grass and/or reduce tall vegetation prior to actual conversion. In fact, unless a field has been grazed or cut for hay regularly, burning will greatly aid in establishing native grasses by removing thick, matty grass, thereby resulting in a more effective treatment of the existing sod and less competition to the native grass seedlings. However, be advised, Kentucky does have fire laws, regulated by the state Division of Forestry (800/866-0555). Basically, from February 15 through April 30 and from October 1 through December 15, you cannot burn within 150 feet of any woods or brushy area except between the hours of 6:00 p.m. and 6:00 a.m. local time. Prior to doing any burning you should consult with the Division of Forestry regarding regulations and techniques. You should also notify the local fire department and adjoining landowners.

Once such preliminary work has been completed, grassy fields should be sprayed with herbicide (Roundup and/or Plateau) to kill fescue* and other vegetation before seeding. Spraying can be done mid to late spring (April-May), or if preferred, during the previous fall (September). Vegetation should be sprayed on a warm sunny day when it is about 8 inches tall and actively growing (bright green). Fall sprayings should consist of Roundup only (1 qt/ac); Plateau herbicide should only be used in spring to capitalize on its residual weed control. One good technique is to do a fall spraying of Roundup (1 qt/ac), followed by a spring spraying of a Roundup/Plateau tank mix (1 qt/ac Roundup & 4-8 oz/ac Plateau). If only spraying in the spring, you can use Roundup only (2 qts/ac), Plateau only (12 oz/ac), or a combination of both Roundup (2 qts/ac) and Plateau (4-8 oz/ac). Spring herbicide applications should be done 2-4 weeks prior to planting. Be sure to consult the Plateau herbicide label regarding limitations on rates for pasture/hayland, land enrolled in the Conservation Reserve Program (CRP), and situations where substantial amounts of wildflowers are going to be planted with the native grasses. Also, do NOT use Plateau herbicide if trying to establish substantial amounts of switchgrass or gamagrass!

Planting native grass into fields where row crops, such as corn and soybeans, have recently been planted and harvested is also a viable option. Regardless of the particular type of crop, the stubble should be mowed fairly short prior to planting. If using this approach, be cautious of potential residual effects of chemicals used to control weeds on the crop field in previous years because these may kill native grass seedlings. If desired, fields could be sprayed and planted to winter wheat in fall, bush-hogged the next spring prior to the formation of seed heads, then planted to native grass.

Seed Mixtures

Native grass plantings done strictly for wildlife habitat should consist of several species of grass, together with some forbs (wildflowers and/or legumes). Switchgrass is excellent for rabbits due to its thick growth form. Little bluestem is ideal for quail, providing excellent nesting cover while maintaining enough bare ground to allow chicks to move freely. As discussed previously, native grass plantings done for production purposes (pasture/hay/seed) should generally consist of 1-2 species of grass (gamagrass, switchgrass, big bluestem, or Indiangrass), together with some lespedeza. For wildlife plantings, a total grass seeding rate of 4-6 pounds per acre should be used, depending on the species being planted and the herbicide mixture used to eradicate the pre-existing sod. For production plantings, 6-8 pounds per acre is more appropriate. Refer to the tables and list included in this handout for seeding rates, sample seed mixtures, and native grass vendors. Note that seeding rates are listed in pounds per acre of Pure Live Seed; be sure to specify Pure Live Seed (PLS) when placing your order! Also, be sure to order early to ensure availability and shop around since prices can vary greatly. With mixtures, you should request that the dealer pre-mix the grasses for you. There is usually little, if any, charge for such service. Do NOT have them mix in the forbs to be included in the planting. Except for wildflowers, you should withhold the forbs from the planting initially and overseed them early the second spring so as to minimize competition to the native grass seedlings during their establishment year. The wildflower seed can simply be scattered on top of the grass seed within the seed box of the no-till drill at the time of planting. If planting native grasses with fluffy seed (bluestems, Indiangrass, side-oats grama), be sure to use a total seeding rate of at least 4 PLS pounds per acre to facilitate use of no-till drills. Also, note that a cover crop (temporary vegetation such as winter wheat, spring oats, and annual ryegrass) is generally NOT used when planting native grass, except on potentially erodible sites. In those situations, apply a light straw mulch in spring then sow a cover crop in fall and bush-hog the following spring prior to formation of seed heads.

Planting Options

There are 3 basic ways to plant native warm season grass. It can be drilled into a herbicide-treated stand of grass, drilled into a prepared seedbed, or broadcast seeded onto a firm, bare seedbed. Although excellent results can be obtained with any of the methods, the first two are the most popular. Broadcast seeding requires seeding rates to be increased, and native grass seed can be expensive. Consequently, that option is likely best suited to plantings done on small fields where the extra cost is minimal.

Drilling into a herbicide-treated stand of grass is simplest, likely results in less weed problems due to smothering by the residual stand of grass, and eliminates the risk of soil erosion. However, seed-to-soil contact, and subsequent germination, may not be quite as good due to the same residual stand of grass. Drilling into a prepared seedbed will likely result in better seed-to-soil contact and germination. However, it requires more field preparation and could result in more weed problems due to exposure of ungerminated seeds, unless Plateau herbicide is used in conjunction with the planting. Also, loose soil of a tilled seedbed could be eroded as well. Overall, most people usually choose to plant native grass by no-till seeding into a herbicide-treated stand of grass, with very good results.

Planting Techniques

Planting depth on native grasses is critical! Gamagrass, having a hard seed the size of a corn kernel, is planted 1-1.5 inches deep on 30 inch rows using a no-till corn planter. All other native grasses are planted ONLY 1/4 inch deep. If you plant them too deep, they will not germinate! It is better to have the seed laying on top of the ground than to have it planted too deep. Switchgrass has a small, hard seed capable of being sown with standard grass drills or broadcast seeders. However, the seed of most native grasses has hairy appendages that cause it to stick together and not flow smoothly through conventional seed drills. Therefore, such seed must be sown using a special type of drill available from the Kentucky Department of Fish and Wildlife Resources, a local conservation district, or a local farm store. These native grass drills have agitators and picker wheels within the seed box to mix the fluffy seed and pull it down through the drop tubes. If using a native grass drill, be sure to keep the box at least half full during most of the planting to keep the seed flowing smoothly. You can normally expect to see as much as 30% of your seed on top of the ground in the drill rows. As mentioned previously, on fairly small, flat sites, broadcast seeding onto a firm, bare, fine-textured seedbed can also be effective. Plow, disk, and cultipack the site as necessary to prepare it. The ideal seedbed should be smooth and barely show footprints. Then use a lime or fertilizer truck, a conventional cyclone seeder, or a hand-held or ATV/pick-up mounted seeder to plant the seed. Increase seeding rates 25%, mix the seed with a carrier (sawdust, lime, fertilizer, oats, cracked corn), criss-cross the field overlapping swaths, and lightly drag, roll, or cultipack the site when done broadcasting to cover the seed and enhance germination. Do NOT disk the site after planting since that will push the seed too deep into the soil! If oats are used as the carrier, they should be clipped off the top of the stand prior to formation of seed heads to minimize reseeding and subsequent competition to the native grasses. Note that it may be possible to purchase native warm season grass seed that has the hairy appendages removed by a process called "debearding". Debearded seed costs more, but may be sown using common broadcast seeding techniques or conventional seed drills.

Lime & Fertilizer

Addition of lime and fertilizer to native grass plantings usually is not necessary, provided the soil pH is above 5. Native grasses are quite hardy and normally do fine on their own, making efficient use of available nutrients. Since such soil amendments* can be quite expensive, landowners may opt to skip this step. However, plantings done for production purposes (pasture/hay/seed) should definitely be limed and fertilized in accordance with a soil test (contact the county Extension office for assistance). Lime should be applied several months prior to planting to allow time for it to become incorporated into the soil (aim for a pH of 6.5). Fertilizer should be applied in mid-summer (July) after seedlings have grown a few inches. Nitrogen should only be used in conjunction with Plateau herbicide (if appropriate). If needed, nitrogen can be top-dressed the second year. Note that some federal programs may require the addition of lime and fertilizer to all native grass plantings, even those that are done strictly for wildlife habitat.

Weed Control

Native grasses have typically taken a few years to become fully established because the first couple years they tend to put most of their energy into developing an extensive root system and generally do not produce much growth above ground. However, research has shown that native grass stands become established much quicker if competing, undesirable plants are controlled. Since weed control is so critical to the survival and productivity of native grasses, the use of special herbicides (Plateau) is very important. Still, the goal of weed control is to regulate their density, not to totally eliminate them. As mentioned previously, in terms of wildlife habitat, the primary purpose of the native grass stands is to provide cover; the wildflowers, legumes, and annual weeds contained within the stand are the main source of food. In fact, many common "weeds", such as foxtail and ragweed, are actually excellent natural food sources for wildlife, especially quail. These valuable native plants are not a problem unless they occur in such dense stands that they outcompete the native grasses for sunlight, nutrients, and moisture.

On most native grass stands, Plateau herbicide can be used to control weeds. On switchgrass, because it is sensitive to Plateau, other techniques must be used. The stand could be top-clipped (mowed above the native grass seedlings) repeatedly during the summer as necessary. Wick-type herbicide applicators, containing booms or arms with cloth wicks hanging off them, can sometimes be used to selectively apply Roundup herbicide directly to taller vegetation without harming native grasses. If broadleaf weeds are the problem, 2,4-D herbicide can be sprayed over the entire field without harming any grasses; however, it will kill legumes and wildflowers within the stand. On gamagrass, standard corn herbicides are effective (atrazine; Accent; 2,4-D). Be sure to follow label directions when using any herbicides. Also, use of some herbicides is regulated and requires a special restricted use permit; check with your local farm store for details.

Maintenance

Once established, native warm season grasses, like all grasses, need to be maintained through periodic disturbance. Sometimes this may be done by moderate grazing* beginning in the second year. In other situations, they may be cut (no lower than 8 inches) for hay*, preferably in July or August to avoid disturbing ground-nesting wildlife. Mowing of native grasses (and all grasses for that matter) for hay should be done when they are in the early boot or seedhead stage to capture maximum nutritional content. It is possible, given two cuttings, to get 4-5 tons/acre/year of forage from some of the native grasses. If not being cut for hay or grazed, native grasses should be maintained by prescribed burning*, strip disking*, or mowing* on a 3 year rotation. A good technique is to plan ahead and install 15-25 foot wide fire lanes of either clover* or annual grains* around the perimeter of your warm season grass stands in preparation for burning them at a later date.

Table 1. Native Warm Season Grass Seeding Rates (PLS Lbs/Ac)

Native Warm Season Grass Seed Vendors

* Other related Habitat How-To references: