A. Bermudagrass that invades lawns is not typically dark green and is not dense in a bunch. It produces stolons so you can usually identify it because it wants to creep along the surface of the lawn.
|Bermudagrass stolon creeping on to the sidewalk|
If it is dark green and in clumps, it might be a fescue or rye. Because bermudagrasses will not grow in shade, if we keep the lawn mown high, do not use line trimmers to edge the lawn, do not mow or line trim the grass next to sprinkler heads and keep it dense and healthy, it usually keeps bermudagrass out due to shading of the soil.
Once you have bermudagrass it is tough to get rid of. You should get it when it first invades if possible. This would be with spot sprays like Roundup in these locations and reseed.
You do this in the fall. After one week you cut or remove the sprayed grass from those locations and reseed it or cut small pieces of sod and resod those areas. Keep it wet the first two weeks as it starts to root into the soil. You gradually back off on the frequency of irrigation and increase the amount on those spots. This forces it to root more deeply. Finally, after about 8 weeks, you revert to your sprinkler system.