Killing Bermudagrass in a Fescue Lawn

Q. How can you kill Bermudagrass growing in an existing fescue lawn?

Bermudagrass invades southern fescue lawns where water is not applied enough or where fescue is mowed too short.

Best Timing for the Mojave Desert: Spring and Fall months (Fall is best when temps are cooler but before it turns brown)

A. It’s much easier to kill fescue growing in a Bermudagrass lawn than it is to kill Bermudagrass growing in a fescue lawn. Your problem is more difficult. You will have to use chemicals if you want to correct this problem. The two chemicals are either Roundup if the Bermudagrass is growing in a few areas or spraying Fusilade if Bermudagrass is growing throughout the fescue lawn. Roundup is “spot sprayed” where Bermudagrass is a problem which kills all the grass in those spots.

Roundup Herbicide on Do My Own Pest Control

Fusilade DX Herbicide on Do My Own 

Roundup will be sprayed in those spots now and through the summer when you see Bermudagrass trying to get established again. And it will try. The lawn is seeded with a good quality fescue seed in those dead spots as early as late September and though October. Until that time, the dead grass is left in place to help prevent the growing of other weeds in those spots.

Fusilade is a grass killer. It will kill all grasses at a high concentration. The concentration of Fusilade sprayed determines if it kills the Bermudagrass growing in a fescue lawn without damaging the fescue or not. So spraying Fusilade at exactly the correct concentration is very, very important. It is best sprayed in a fescue lawn in late September or October. As a warning, it is normal to see the fescue lawn becoming “yellowish” after it is sprayed with Fusilade. Be sure to follow the label directions exactly.

Prevention is the First Step

Preventing Bermudagrass from getting established in a lawn is the most effective way to control it in a fescue lawn. 

Improve Irrigation. Water must be applied evenly to lawns. Make sure the water is applied as evenly as possible to the lawn area. Water should be applied "head to head" when sprinklers are designed. Check the water pressure of your system and match it to the nozzles used and spacing.

Odd shaped areas of lawn should be removed. Water from neighboring sprinklers MUST overlap each other "head to head". The only way to do that is to match the water pressure with the nozzles used and the spacing of sprinkler heads.

Mowing Height. Keep the mowing height above 2 inches. Lawns that I have seen are mowed too short. Mowing short encourages Bermudagrass invasion.

Keep lawns dense and thick. Dense and thick lawns are encouraged by regularly fertilizing, mowing high, and using the right kind of fertilizer. Lawns in our climate should receive fertilizer applied at least four times each year; Labor Day, Memorial Day, Thanksgiving and Halloween.

            Clean mowers before they are used. A strong stream of water from a hose that cleans the blades and deck is necessary each time you mow. Avoid line trimmers to edge a lawn. If it must be used, never cut the edge of the grass at an angle or use line trimmers around trees or sprinklers.