8/2/2016 11:08 AM
For the future, we use red spray dye in our RoundUp tanks so that it is immediately known that there was RoundUp in the tank. Red also blends well with mulch and pinestraw.
In the mean time, as others have said, communicate. I would guess that you will be looking at some dead spots for a few weeks, but it's early enough in the summer that it should grow out by fall.