It sounds like black spot has infected your rose foliage and this is a fungal infection encouraged by wet foliage and poor air circulation. Full sun will help to discourage this disease but you can control it by removing all infected leaves as soon as they appear and do not let the rose dry out. Fertilize after the first flush of blooms to encourage more flowers and fresh foliage. A fungicide spray made for roses can be sprayed onto the leaves following the instructions on the label. Black spot may look unsightly but it rarely kills a rose don't worry too much. Clean up all fallen leaves from the ground so they don't spread any disease spores. A fresh bark mulch on top of the soil should help seal in existing disease spores. Keep growing, Marianne Binetti