I got a customer who has a long road that is a drive to his home. I mow all the ditches weekly and have for years. He aproached me about cuttign down the grass growing around the culverts and some areas that are just too steep to mow or trim. Is there a chemical that will burn down the foliage but leave the roots intact, so not to cause erosion and not kill off the grass? With all the areas its about 2k sq ft. Like I said most is just way to steep to trim.