When roses are pruned depends largely on the type of rose. Roses that bloom once on new growth are pruned in early spring. Roses that bloom once on old growth are pruned after flowering. Roses that bloom more often are pruned at different times dependant on species.
Dead, damaged or diseased branches should be removed from rose plants regardless of the time of year. Identifying exactly the type and species of rose is key for proper pruning. Most rose plants are hardy enough to survive a bad pruning, and mistakes grow out rapidly. It is therefore better to attempt pruning than to allow roses to run wild.