Certified GKH Gardening Expert
Normally, roses are pruned in spring or in fall when dormant. However, others say that is old advice and pruning during growing season allows quick healing of cuts.
You can cut shrub roses back by about half if needed. Cutting back climbers may sacrifice blooms if next year's blooms are already developing. If they are Knock Out roses, they are pretty forgiving and you can cut them back by half now and it shouldn't hurt them.