When should I prune my roses and other shrubs?
Roses should be pruned in the early spring just prior to the emergence of new growth. When pruning roses, first start with any branches that are dead or diseased. Next remove the weaker of any two branches that are crossing. Cuts should be made just above a bud that is growing to the outside.
Angle the cut toward the inside. Prune out branches that are growing toward the center of the bush. Lastly, prune the top of the rose bush to a height that you choose. The general rule is to not remove more than one-third of the plant material during any pruning event. It is a good idea to disinfect your pruners before moving to another plant. Disinfect your pruners with a spray of alcohol or by dipping the pruners into a bleach solution made of one part bleach to 19 parts water. Be sure to oil your pruners when finished.
Keep an eye out when starting to prune. Mottling, yellow patterns on the leaves or discoloration on the foliage can be signs of a virus. If you notice any mites, be sure to disinfest your pruners before moving to the next plant. Two spotted spider mites can cause foliar damage. Eriophyid mites can transmit Rose Rosette Disease to other plants. Rose Rosette Disease is identified by an excess of small thorns and small leaves with a great deal of red color on the shoot growth. These plants must be removed and disposed of.
The general rule for pruning blooming shrubs is to wait until after the shrub has bloomed before you remove plant material. Prune Forsythia after the blooms are gone. For late summer blooming plants, they can be pruned now. The new growth will provide the blooms later. If you have an oversized shrub that doesn't bloom as well as it did, you will have to do a multi-year pruning to renew the younger growth. As with the roses, don't remove more than a third of the growth in a given year as this will stress the plant. For shrubs that have grown to tall, you may have to reduce the height of the shrub along with one or two wayward branches and then remove some older wood each year until you have propagated new growth. It is always better to prune a little each year rather than to neglect pruning a shrub for several years and then try to correct the overgrowth all at once.
If you would like to have a fact sheet on the care and pruning of roses and shrubs, contact your Extension Office for HLA-6403 (roses) or HLA-6409 (shrubs).
For more information contact the OSU Extension Center, 14001 Acme Road, corner of MacArthur and Acme Road in Shawnee or 273-7683.