Things You'll Need
Bermuda and Centipede are two popular warm-weather grasses that are commonly used in lawns. Bermuda grass spreads out and is more aggressive than Centipede grass. If allowed to grow unchecked, Bermuda grass will overtake (or choke off) Centipede grass. Unless it is completely removed, which is difficult, Bermuda grass will keep coming back. Attack Bermuda grass with either chemicals or manual methods.
With a Herbicide
Keep the patches of Bermuda grass well watered. You can also fertilize the patches to encourge their growth. Don't mow the grass. A herbicide is absorbed better when the grass blades are long.
Spray the Bermuda grass thoroughly with an herbicide that has a glyphosate solution. Read the directions on the package to see how many applications are recommended. Know how long you should wait between applications.
Allow the Bermuda grass to absorb the herbicide for at least three days.
Remove as much Bermuda grass as you can manually. Rake out dead grass. Use a hand spade to dig out Bermuda grass and its roots.
Wait a week to see what Bermuda grass has survived. Spray the herbicide again, and repeat steps listed above.
Keep an eye on the lawn in future years, and retreat with herbicide if any Bermuda grass grows back.
Cut the grass with the mower set to its shortest height. Dig out as much Bermuda grass as you can by hand. Dig at least 4 inches to get at the roots. Dispose of the Bermuda grass in trash bags.
Kill the Bermuda grass with a method known as plastic mulching. Cover the grass with a thick, black plastic sheet in the late spring or early summer. Weigh down the sheet, and leave it in place until late summer.
Cover the areas where you pulled the Bermuda grass with newspapers. Weigh down the newspapers, and leave them in place for at least two weeks. This method is not as thorough as plastic mulching, but it will kill a lot of Bermuda grass.
Do not attempt to remove Bermuda grass by hand prior to applying a herbicide. This will make the herbicide less effective. Don't spray herbicide on Centipede grass, or any other plant life in the area.