Q: I replaced my bermuda lawn with zoysia in late April of this year. The contractor sprayed the bermuda with some sort of herbicide cocktail and the grass turned brown in a matter of hours. Five days later he scalped the brown sod with a string trimmer and laid the zoysia on top of it. The zoysia quickly established. But recently I’ve noticed bermuda growing in the zoysia. Is this bermuda is coming from my old lawn or could the new sod have been contaminated with it?
A: It is coming from your old lawn. There is no herbicide in the world that will completely kill bermuda grass with one spray and allow planting sod five days later. It usually takes two sprays, two weeks apart. Sometimes three sprays are required. In addition, it is bad practice to simply scalp the existing lawn and lay sod on top. The soil should’ve been thoroughly tilled and raked smooth before laying sod. You are now going to have a hard time killing the bermuda grass in your zoysia.