Rose Issues

It looks as if there are a few things going on here.
It is hard to see clearly but there is probably a fungal leaf spot disease. It is difficult to tell from this photo which one it might be but both are treated more or less the same: No overhead watering, remove and properly (do not compost) dispose of all affected plant parts and litter, provide the plant with it’s optimum growing environment (full sun; rich,well-draining soil; fertilizer formulated for roses; enough water to sustain the plant). Here is a link that might be helpful: http://www.ipm.ucdavis.edu/PMG/GARDEN/PLANTS/DISEASES/leafspotdis.html
The way the rose is withering suggests not enough water. You would be the one who would know that.
By the looks of the photo, there may not have been enough amending of the soil to ensure the success of the rose plants. Also, the weeds compete with the roses for water and nutrients in the soil. The weeds are best removed.
Her a couple of other links that you might find helpful: http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7465.html
http://www.ipm.ucdavis.edu/PMG/GARDEN/PLANTS/rose.html