Bright green Bermuda grass (Cynodon dactylon) thrives in U.S. Department of Agriculture plant hardiness zones 7 through 10. Few other grass species so perfectly illustrate the cliche, "One man's trash is another man's treasure." Prized for its ability to spread and fill a once-barren patch of dirt, Bermuda grass cropping up in the midst of a yard full of other grass species may be considered a pest. Some herbicides, like Scotts Bonus S Southern Weed & Feed, can injure or kill Bermuda grass as well as some other grass species.
Scotts Bonus S Southern Weed & Feed is only sold in the Gulf states -- Florida, Texas, Louisiana, Alabama and Mississippi, and in South Carolina. The product is a granular mix of herbicide and fertilizer to help clear eliminate weeds and undesirable grass species while providing nutritional support to desirable grass.
Scotts Bonus S targets weeds and undesirable grasses in St. Augustine grass (Stenotaphrum secundatum), hardy in USDA zones 8 through 10; centipede grass (Eremochloa ophiuroides), hardy in USDA zones 7 through 10; zoysia grass (Zoysia japnoica), best for USDA zones 5 through 10; and carpet grass (Axonopus affinis), suitable for USDA zones 9 through 10.
While the fertilizer component of Scotts Bonus S is unlikely to harm grass species, the herbicide portion, atrazine, can harm not only the warm-season Bermuda grass but also cool-season grasses like fescue (Festuca L.), hardy in USDA zones 4 through 7, and bentgrass (Agrostis L.), hardy in USDA zones 4 through 6.
Bermuda grass has some tolerance for atrazine-based herbicides, according to the University of California's Statewide Integrated Pest Management website. This means that trying to eliminate Bermuda grass using Scotts Bonus S may not work.
Using Scotts Bonus S
A drop or rotary spreader is generally the best equipment for spreading granular Scotts Bonus S evenly over the lawn. Settings for various types of spreaders are listed on the bag. The product may be used in spring, fall or late winter and is available in sizes to treat 5,000-square-foot lawns or 10,000-square-foot lawns. The herbicide kills 25 common weeds, according to the product label, and the 29-1-00 fertilizer mixed with the herbicide helps strengthen appropriate grasses against hot Southern summer heat and drought. Label instructions state the product is most effective when weeds and undesirable grasses are young and actively growing. Once the product is spread on the lawn, it should be watered in thoroughly.
If your aim is to kill Bermuda grass in the yard and the first application of Scotts Bonus S fails to kill the grass completely, a second application may be made. Wait two months and treat the yard again. Because Bermuda grass may exhibit some tolerance to the atrazine in Scotts Bonus S, the second application may not completely kill the grass.
Other Chemical Controls
Eliminating Bermuda grass is never easy. The grass reproduces by seed above ground and via rhizomes and stolons underground. Herbicides specifically formulated to kill unwanted Bermuda grass are readily available. These herbicides use other chemicals instead of atrazine for effective Bermuda grass control.