Bermuda grass, or Bermudagrass (Cynodon dactylon), was introduced from Africa in the 18th century and is commonly used for turf, in gardens and roadsides and planted for livestock forage. It is also considered an aggressively invasive, noxious weed that is widespread throughout the American south, southwest and California. Bermuda grass spreads by rhizomes below the surface and stolons on top of the ground.
Withhold water from the Bermuda grass in the summer to dry the stems. Space or rototill the area three or four times during the summer to bring rhizomes to the surface to dry out. Remove the rhizomes and stolons with a rake. You can bring the majority of the rhizomes to the surface with one cultivation 6 inches deep, but it will take weeks or months to dry those still in the soil. Do not cultivate wet Bermuda grass because each stem you chop into a separate piece will become another plant. Cultivating and drying can kill established plants, but not the seeds still in the soil.
If you increase the shade from tall shrubs and trees, the shaded Bermuda grass will be spindly and fine, much easier to remove than those growing in full sun.
Mow and irrigate the grass, then cover it with a layer of black polyethylene; leave it for 6 to 8 weeks in the summer. Make sure the plastic doesn't have holes or the Bermuda grass will grow through them. This method will not work in the winter.
Bermuda grass will grow through a mulch of wood chips unless they are placed over organic landscape fabrics that will ultimately decay.
Clear Plastic Mulching
Called solarization, covering the Bermuda grass with clear, ultraviolet protected polyethylene during the hottest summer months---from June to August in most places---kills the turf by roasting it. Mow and remove the clippings and water well before applying the plastic. When you finish solarization, do not cultivate more than 3 inches deep to avoid bringing seeds near the surface where they can germinate. The plastic should extend 2 feet beyond the Bermuda grass stolons to make sure the grass is completely covered. Mulching with black plastic will not kill seeds remaining in the soil; mulching with clear plastic will.
The best time to apply grass-slective herbicides is in the early spring when the Bermuda grass is less than 6 inches in length. Reapply the herbicide before the grass again reaches 6 inches. If necessary, reapply through the spring and summer. Read the product label to determine the total amount you should use per area. It is best to apply these herbicides when the Bermuda grass is growing vigorously and is not suffering damage by insects.
Horticulturalists at the University of California, Davis, recommend grass-selective herbicides containing sethoxydim, fluazifop or clethodim. These herbicides will kill grass but not broadleaf plants.
Herbicides containing glyphosate kill all of the Bermuda grass including the roots. Apply it when the grass is growing vigorously and has lots of leaf surface. Do not mow the grass for two to three weeks before you apply the herbicide. After applying, wait for a week before you cultivate or mow the grass. If you cultivate the grass after applying the glyphosate herbicide, you can bring the rhizomes to the surface to dry. If you don't cultivate, some rhizomes can regrow the grass.
You can apply herbicides containing diquat, perlagonic acid and glufosinate, but they will injure everything they touch. Since they kill only green leaves and stems, these herbicides leave the rhizomes under the soil untouched. However, application of these herbicides might suppress the Bermuda grass and give a desirable turf species a chance to grow.