The Best Time of Year to Cut Back Rose Bushes and Knock out Roses

Benefits of Pruning

• Understanding the benefits of and reasons for pruning before picking up the garden sheers is important because this knowledge will help guide your cuts. Pruning helps improve airflow within the rose bush. Good air circulation is necessary to reduce the risk of fungal disease and mildew buildup. Pruning away dead and damaged canes also keeps your rose plant healthy. In addition, pruning stimulates new healthy growth, improves the quality of the blooms and produces abundant flushes of flowers.

When to Cut Back

• When to prune roses depends on local climate conditions, but there are several rules of thumb to help determine the best time in your area. First, wait until the last winter frost has passed because you don't want to expose any new growth to cold damage. For much of the United States, January and February are the best months to prune rose bushes, but in regions with harsh cold winters, it is better to prune in early spring. Another guideline is to prune roses when forsythia begin to bloom. Also, look for swelling buds -- a sign the bush is emerging from its dormant period -- as a sign to prune. Knock Out roses are not pruned until the bush reaches maturity, typically after their second or third growing season. However, any diseased or damaged stems should be pruned regardless of the time of year.

Pruning Steps

• The first step when pruning a rose bush is to remove any damaged or dead canes, identified by a blackened or shriveled appearance, cutting as close to the plant base as possible. Next, you want to prune to improve airflow by cutting back four to six of the healthiest canes into a traditional urn or vase shape. New growth will return quickly; Knock Out roses were bred to flourish, so you can safely prune away one-third to one-half of the height you desire for the coming growing season. That is, if you want a 4-foot bush, then prune canes to 2 feet.

Tips

• Remove any fading flowers throughout the growing season to encourage new blooms. Also, when pruning, wear leather gloves to protect yourself from thorns. Use bypass pruners, which make cleaner cuts, rather than those with an anvil head. To prevent the spread of disease, dip the pruners in a 70 percent alcohol solution between cuts. After late winter or early spring pruning, fertilize your rose bushes and Knock Out roses as an added boost to new growth.