Crossbow Herbicide  is not supposed to harm established grasses in the listed areas, but it does contain Triclopyr which can injure bermuda.  This being said, we always recommend treating a small area first to test the results.  As long as your grass is not stressed by drought and it is healthy the grass will not be harmed. We do not suggest applications during the heat of the day and while other stress factors to the treatment surfaces, nor during transition periods in spring and fall.