It sounds as though your roses are suffering not from bad soil but from a fungal disease such as black spot or verticillium wilt. Verticillium fungi live in the soil and enter plants through their roots, spreading through the canes by means of water-carrying vessels in the stems. The fungi block these vessels, hampering the movement of water and nutrients through the plant. The leaves will yellow at the edges, then turn brown and dry. Foliage will wilt in hot weather. Verticillium wilt has no chemical control, but fertilizing and watering your roses may promote fresh vital growth. For a more specific diagnosis, take a plant sample to a local garden center or to your cooperative extension service.