Posted: 16/05/2012 at 11:55
Roses are pruned in spring, Feb-March, and even then they're not usually cut right back. If you prune them now, you'll lose all the flowers. Your best bet is probably to let them flower, but when dead heading cut the branches back to an outward facing bud about 6" from the ground.
That will encourage them to shoot from near ground level, and in future you'll be able to prune more lightly to maintain a good shape.