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GARDENING: St. Augustine grass can make an attractive lawn

St. Augustine grass is an attractive turfgrass that has large flat stems and broad coarse blue-green leaves. It forms a dense thick turf that spreads by long, thick above ground runners. St. Augustine grass is similar in appearance to centipede grass, but its leaf blades are thicker in width and the tip of it does not have as sharp a point.

It is the most shade tolerant warm season grass. It does well in filtered shade but not deep shade. St. Augustine grass lawns are established by sod or sprigs, not by seed. When properly installed and maintained, a St. Augustine grass can be a beautiful lawn for homeowners.

St. Augustine grass is the lawn of choice in South Georgia and Florida. In North Georgia, the winter temperatures can drop to levels that can potentially cause harm to the lawn. However, many St. Augustine grass lawns in our area have survived the past couple of cold winters without suffering from any major damage. Newer varieties have been developed in recent years that can tolerate colder temperatures.

For established lawns, apply all-purpose turf fertilizer after the lawn has come out of winter dormancy and greened up in the spring and again in early summer. Do not apply any fertilizer after the end of August as doing so will delay it from going into winter dormancy, thus increasing the chances of cold damage.

St. Augustine grass should be mowed at a height of two to three inches. Mowing it too low can increase its susceptibility to drought stress, insect and disease problems. Never remove more than one-third of the leaf blade at one time. St. Augustine grass is tolerant of dry conditions, but it will need supplemental water applications during prolonged dry spells for the lawn to maintain an optimal appearance.

Thatch can sometimes be a problem, especially if the lawn receives excessive amounts of water and high nitrogen fertilizer. Thatch is a layer of roots, stems, and shoots between the soil surface and the leaf blades that have not completely decomposed. If it gets over one-half of an inch thick, it can harbor insects, diseases and disrupt the penetration of air and water. Avoid applications of excessive amounts of water and fertilizer. If thatch is a problem, use a core aerator during the growing season to break up the layer.

St. Augustine grass is highly susceptible to chinch bugs, which are small silver to black insects one-eighth of an inch long. The main symptom of chinch bug activity is patches of yellow to brown areas of dead grass that begins to spread. The insects are most problematic during periods of hot, dry weather and are most active in areas of the lawn that are in full sun.

If you suspect chinch bugs are infesting the lawn, get a tin can and cut off both ends. Push the can into the soil where the green, healthy grass transitions into the affected grass and then fill it with water. The chinch bugs will float to the surface. Chinch bugs can be controlled by insecticides, such as Sevin, Bayer Advanced Multi-insect Killer Granules, or Ortho Bug-B-Gon MAX Insect Killer for Lawns. Keeping the grass healthy through proper cultural management methods will improve the lawn's resistance to chinch bug infestations.

Several improved varieties of St. Augustine grass are available. "Floratam" and "Floralawn" have a greater resistance to chinch bugs. "Raleigh" is the more cold tolerant variety. "Seville" is a semi-dwarf variety with a dark green, fine texture, but is not as cold tolerant as some of the others.

If properly installed and maintained, St. Augustine grass will thrive and provide homeowners with an attractive lawn.

Timothy Daly is an Agriculture and Natural Resources Agent with Gwinnett County Cooperative Extension. He can be at timothy.daly@gwinnettcounty.com.