Rubber Mulch may or may not work in a steep area. A customer used it in her back yard and her side yard was quite steep and the rubber mulch stayed in place with no problems. However, I would not go so far as to say this would be the case every time and in every situation. You might want to test a small area out and then make your own decision as to whether you want to make the investment. Please call any time at 815-436-5587. Good question.