Rose growers --- both amateur and professional --- have debated the merits of pruning for as long as roses have been cultivated. All pruning decisions are dependent on the type of rose, the age of the shrub and the climate in which it grows. Fall pruning decisions are no different. Some gardeners worry that pruning too much in the fall will weaken the plant so much that it will be unable to withstand winter temperatures in cold winter areas. This is generally not the case.
Fall is a long season, and pruning decisions should be made according to where you live. Labor Day is a good time to prune and has the benefit of being an easy-to-remember day. However, if your area has a relatively long growing season, the pruning can be postponed until mid- or even late September. Well-established plants won't be harmed by late fall pruning.
Prune out any dead or diseased canes, removing those that cross each other. The first fall after planting, cut young rosebushes --- except for climbers and ramblers --- back hard, to within 3 to 6 inches above the ground. This promotes healthy growth from the base of the plants and prevents the roses from becoming "leggy." Climbers and ramblers should be left alone for the first two or three years. After that, they should be pruned and trained to promote the lateral, or horizontal, growth. Once-blooming and mature reblooming roses should be tidied and pruned to shape.
Fall pruning creates a healthy rosebush by eliminating the weakest canes, encouraging air circulation, promoting strong basal growth and preventing winter damage to the shrubs. Removing and disposing of ailing canes prevents the spread of disease.The long canes of unpruned bushes can be prone to being whipped around by winter winds, potentially causing damage to the rest of the bush. Fall pruning also lessens pruning chores in the spring, the busiest time of the gardening year.
Successful pruning requires sharp secateurs, or clippers; loppers; and sometimes a pruning saw. Clean the tools before you use them, and wipe the blades periodically between cuts and when moving from one shrub to another. Wear stout gloves and a long-sleeved shirt to minimize scratches. To deter cane borers, paint the cut ends of the rose canes with a small amount of white glue after pruning.