GROWING A RIVER

by Cathy Ramsey, Contributing Author for Plateau Land & Wildlife Management

Paddling down a river is my favorite way to spend time near my home in Central Texas. The grassy hills and rocky, undulating terrain make for gushing springs and clear rivers offering up a seemingly endless succession of gentle rapids, stepping you down the stream one after another. The cool currents guide you through the countryside, rich with birdsong, wandering wildlife, and rustling breezes. What could possibly mar such a scene?

How about drought.

Dry periods are also a part of nature here, and while dreams of drifting down a full and lazy river may come to a screeching halt, they're prime time to prepare your land to take full advantage of every drop when the rains return. One key preparation is reestablishing native grasses.

Grasses are exceptional at building soil and aiding water infiltration, and can be managed to resupply our groundwater. The ideal time to seed our native warm season grasses is March and April. If you have bare areas or non-native pastures you want to convert back to native grasslands, now is the time to act.

Much of Central Texas was historically a mixed grass prairie, shorter on the ridge tops, mid-height on the slopes, and tallest in the bottom lands. Prairies absorb more water than they use, which resulted in huge aquifer reserves producing plentiful springs and abundant rivers. Since Texas became a state, farming, overgrazing, and development have changed things considerably. Less than .1% of this native prairie remains intact, and our springs and aquifers are diminishing at an alarming rate. We have already lost over a third of our historic springs, and more go dry all the time.

Reestablishing native grasses is an important step in water conservation, stream and river restoration, and the rewards become apparent in a relatively short time.

Reestablishing native grasses
Yard areas can be planted with shorter natives such as buffalo grass and blue gramma, and bordered with beds or swales of taller grasses to catch any runoff coming from the shorter yard. In areas of heavy deer traffic, taller bunch grasses such as big muhly and switchgrass can stand in for shrubs which deer can't seem to resist. Reseeding even a portion of your property can help reintroduce native seed stock which will spread with time. Choose a mix appropriate to your soil, and start with the early successional grasses which establish quickly, including blue and sideoats gramma, silver bluestem, green sprangletop, and bristle grass. Climax grasses such as little bluestem, switch, and indiangrass can be seeded simultaneously, but may take a bit longer to become established, particularly in dry years. Finally, throw in some Texas cupgrass seed, a beautiful and almost evergreen grass endemic to our area, which has the added bonus of being a favorite of painted buntings.

Once established, it's important to let the native grasses maintain their natural height. Mowing too frequently will prevent the bunch grasses from seeding, and eventually leave them vulnerable to competition from fast growing non-natives such as King Ranch bluestem and bermuda, which spread by both rhizome and seed. While occasional grazing or mowing at the highest setting possible is appropriate and beneficial, as described below, native prairie grasses maintained at their natural height have a network of roots extending deep and wide, loosening the soil to create a sponge-like layer. The taller the grass, the deeper the roots, and the better the possibility of infiltration with each rain, no matter how fast and hard it comes down. Some of these grasses have roots in excess of 17 feet deep! These taller grasses catch and hold water droplets along their stems, allowing absorption to continue after the rain has ended, and increasing overall intake into the soil. They also shade the soil, reducing evaporation and reflected heat, and act as filters, reducing pollution. Water that has filtered through the soil is not only purified, it's also cooled. When it's released through spring flow, rather than running over land as runoff, the temperature of our streams is stabilized, and our swimming holes stay clear, chilly, and inviting.

Know when to mow
Mowing once a year, generally in mid-February in most years, and perhaps again in early July during a wet year, is sufficient. Leaving alternate portions alone for a two year stretch will allow biennial forbs to become established, and provide cover and nesting structure for wildlife. In direct contrast to the benefits of grasses left at their natural height as described, above, short grass grows short roots, shrinking the active layer of life in the soil and reducing the ability of the soil to absorb water. Without the shading of taller foliage, the ground dries out faster and becomes hard, making the next rain less likely to be absorbed. The grass becomes dry and brittle, increasing fire danger. Considering that many of our natives, especially little bluestem, put on strong growth and begin seed production during the dry season of July and August, short mowing at that time places non-natives at the advantage. Moreover, the new growth present on the natives contains moisture brought up from deep in the soil and is less likely to burn than short, dry grass. If the grass is closely cropped at this time, more soil is exposed, and more heat is reflected. A tall meadow is noticeably cooler during the heat of the year; walk a path through one and feel for yourself! Lastly, too-frequent mowing increases compaction due to the weight of heavy equipment, further stifling root expansion and aeration. Runoff increases, erosion increases, and stream quality suffers.

If you're a fan of beautiful rivers, remember them when planning your landscape and managing your land. A big stand of native grass is not only a pleasure to view, swaying gently in the breeze, but is water in the bank and savings for the future.

Reestablishing native grasses is an important step in water conservation, stream and river restoration, and the rewards become apparent in a relatively short time. Photo by Lee Kothmann.