Both Bahia grass and Floratam are warm-weather grasses that are used extensively in the southeastern United States. Both types have properties that make them suitable for the climate in Florida and along the Gulf Coast, but there are also differences that should be considered. As with all grasses, dense growth is the best way to ensure that the weeds are crowded out. Proper maintenance will help to keep these grass types thick and healthy.
Bahia is a tough grass that grows densely, making it strong against heavy foot traffic. It is strong against hot climates and has a distinctive "Y-shaped" seed head after it has sprouted. It is an aggressive grass that can become a hard-to-remove weed for some homeowners. It is impractical to remove Bahia grass after it has been planted, and weed removal programs should aim to control the grass to tolerable levels instead.
Floratam grass is a relatively recently developed grass brought to the rest of the United States from Florida. It is an improved form of St. Augustine grass released in 1973 by local universities hoping the plant would be more resistant to local environmental threats. Unfortunately, this grass has difficulty tolerating herbicide in high temperatures, and its natural resistance to chinch bugs has diminished since its release.
Many broadleaf weeds attack bahia and floratam grasses, stealing nutrients and crowding them out before they have a chance to grow. Such weeds include dollar weed, spurge, and knotweed, which are all common problems. Other grasses can become weeds to these lawns, such as crab grass and goose grass, which are aggressive plants that will fight to spread quickly, especially in unhealthy grass landscapes.
The most effective way of treating weeds that are invading your lawn is to use pre-emergent herbicides that keep weeds under control by preventing germination. Hot-weather grasses such as Bahia and Floratam are easily damaged by post-emergent herbicides. Pre-emergent herbicides contain chemicals such as bensulide, pendimethalin, dithiopyr and benefin, which work well against weeds when properly used on a regular schedule every year. Weeds that have already broken the surface of the lawn should be removed manually either with a weed whacker or by hand.
The best way to keep weeds under control within your lawn is to keep your grasses in a healthy state. This will produce strong root systems that can keep otherwise healthy weeds from germinating within the lawn. Overwatering, underwatering, infrequent mowing and nutrient deficiency can all cause a sudden increase in weeds that could have otherwise been avoided.