While caring for roses in winter, you need to take care of other factors too apart from pruning. You need to get rid of any fallen leaves or weed near the plant. Also, you need to protect the graft union, by circling the rose with wire and covering it with mulch. Watering the soil around the plants after the first frost is also a good idea, as the plant will have to take care of itself once the ground freezes.
How and When to Prune Roses for Winter
Pruning roses in order to prepare them for the winter season should be done late in the fall. In spring, the rose shrub will be blossoming with many flowers. At the end of the season, let all the foliage be on the plant. The flowers will get converted into hips, which will give the plant an indication that it is finished growing for this season, and it will go into dormancy. So, observe the plant to check for full dormancy, or when it has shed off all its leaves. This is the right time for the plant to be pruned and prepared for the winter.
While pruning roses, it is important that you never cut the main stem which is the trunk of the plants (not in case of climber roses plants). Light pruning allows many flowers to grow, wherein only stubs are removed. Moderate pruning offers larger blossoms, but fewer in numbers. While for exhibition-size blooms, the bush is pruned severely, and the number of blooms is reduced a lot. For gardening purposes, moderate pruning is advised.
To start pruning, gather the required garden tools, which are bypass pruning shears and long handled loppers. Also, a pair of thick and long gloves are required to protect your hands from any scratches. Apply a little bit of alcohol on the tools to make them sterile.
Now, check for any diseased, damaged, dry, and old branches. Observe if the plant has any suckers growing. Also, look at old and dry canes. These are things which need to be pruned out from the plants.
Moving to the actual steps, grab the shears/loppers and start making clean cuts to rid the plant of unwanted branches and canes. Making a clean cut means cutting the stem at a 45° angle in outer direction from the center of the plant, and just a bit above the leaf bud.
First, start pruning out stems that have hips or dried flowers on them; then start cutting dry stems or stems which have no leaves on them. Now, slowly progress to the lower part of the plant, and cut down dry or diseased branches. While cutting, try to maintain an open vase-like shape of the plant. Then, slowly progress to the desired pruning height of the plant., and finally get rid of the suckers growing on the ground.
Whenever making a cut on the plant, remember to do two things: Always check if the cut you have made shows a white plant tissue in the stem., which means that it is healthy. If you see the inside of the stem to be brown, then it means that the stem is dry or dead. In this case, keep cutting it further till the white part is revealed. Rubbing a bit of alcohol between each cut, or painting the areas where you made the cut, will prevent any insects from infesting the plant.