Institute of Food and Agricultural Sciences
Hendry County Horticulture News
Lawn Grasses for Local Conditions
Newcomers and visitors to Florida often remark on the coarseness of the local lawn grass. They are referring usually to St. Augustine grass, our main turf grass. Despite its shortcomings, susceptibility to drought and the chinch bug, St. Augustine performs very well in our area. It is highly competitive against weeds, usually smothering them, and it does well in diverse soils, under salt stress, and in moderate shade. The superior adaptation of St. Augustine grass extends to low maintenance situations, such as canal embankments, where it generally performs better than Bahia grass, as long as there is a source of moisture. The widespread expansion of St. Augustine grass in Florida and other coastal areas is partly a function of the widespread installation of fixed irrigation systems, and an efficient turf production industry.
The Floratam variety of St. Augustine grass was released by the University of Florida and Texas A & M University, in 1973, for its resistance to the chinch bug and SAD virus. In Florida, where the chinch bug is a serious problem, Floratam was eventually overcome by a virulent race chinch bugs. Floratam has excellent tolerance to the herbicide atrazine, the main pre- and post emergent herbicide used in St. Augustine grass, and it has aggressive stolons (above-ground runners) that can grow laterally at 3/4 inch per day.
St. Augustine grass winter kills when temperatures reach 16 to 20 degrees Fahrenheit (-9 to -7 degrees Celsius). New dwarf varieties have been released since 1975 with lower growth habit, and better shade and cold tolerance than Floratam. While none has yet captured a major niche, Seville, Delmar, and Palmetto are examples of good performing dwarf St. Augustine grasses.
With roots extending to 8 feet, Bahia grass is very drought resistant. It does well in sunny areas in warm humid regions. In Florida, Bahia grass survives in level areas with no irrigation, but often fails on sandy embankments and alkaline soils. It can also be ruined by excess watering and by excess fertilization. Bahia grass normally goes semi-dormant during winter, yet folks sometimes fertilize and water it to keep it green in winter, and thereby encouraging weeds.
There are no post emergence herbicides for grassy weeds in Bahia grass, which is a problem. Most weed problems in Bahia grass could be avoided by proper seed establishment and timely mowing. In summer its rapid vertical growth and exuberant seed head production are remarkable.
The Argentine variety of Bahia grass is superior to Pensacola for use as turf in south Florida. It has a more abundant root system and is lower growing than Pensacola. For most turf purposes, seed should be planted in the spring at about 7 -10 pounds per 1000 sq. ft. in clean seed beds, incorporated 1/4 to ½ inch deep, and pressed in. Straw mulch is helpful in stand establishment. Proper watering is critical, seed should be kept moist until germination occurs. Fertilization should be postponed until about the 5 weeks after planting, or after seedlings have begun to tiller, and have adventitious roots. Soon, within 2 months after planting, or whenever weeds have begun to be competitive, the area should be mown.
Described as one of the world's worst weeds, and the world's most widely distributed plant, Bermuda grass gives remarkable service to humanity. From rich pastures to close, fast greens, Bermuda grass recovers rapidly from leaf removal. This makes turf varieties such Tifway and Tifdwarf Bermuda grasses the main choice for golf and sports turf throughout warm regions. Propagated vegetatively, protected from competition, and re-divided frequently, a square meter of Bermuda grass could expand in one year to cover half the land mass of the earth. Unfortunately, Bermuda grasses have poor shade tolerance and a few other problems. The fine texture of the turf varieties makes visual inconsistencies more obvious, and at their appropriately close height of cut, they must be mown with reel type mowers. To take advantage of the rapid growth rate potential of Bermuda grass, high rates of fertilizer are required, compared with other turf species, and the higher rate of nitrogen often contributes to secondary problems, such as micro nutrient deficiency and outbreak of caterpillars.
While Bermuda grass is often used for lawns in the southeastern United States, it generally does poorly for lawns in Florida. This is due in part to the ravages by the sting nematode. Other sting nematode susceptible turf species, such as zoysia grass and centipede grass, do poorly on the deep sands, common to our area, which are prone to nematode problems.
The lawn is an integral part of the landscape. Not only do lawns contribute to the aesthetic and economic value of the landscape, they also provide recreational surfaces, erosion control and other ecological benefits. Choosing the proper grass is important and the decision should be carefully made, depending on the needs and wants of the homeowner as well as the physical realities of the site. Good luck and good gardening.
Gene McAvoy is the horticulture agent with the Hendry County Extension Service. Direct your horticulture questions to PO Box 68, LaBelle, FL 33975, e-mail - firstname.lastname@example.org or phone 863-674-4092 or 863-983-1598. You are also welcome to visit the Hendry County Extension Office at 225 Pratt Blvd., LaBelle. Office hours are from 8:00 - 5:00.
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