To prune or not to prune, that is a question we often hear from home landscapers. Pruning actually helps keep trees and shrubs vigorous and can add years to their usefulness. Now, late winter/early spring, is often an ideal time for pruning, especially deciduous trees. They are just coming out of winter dormancy and pruning will encourage new growth. Evergreen trees can be pruned anytime the wood is not frozen. Avoid pruning in August through mid-September since pruning encourages new growth which may not harden sufficiently before winter increasing the danger of winter damage.
It is wise to review your trees and shrubs this time of year to determine if they meet any of the basic reasons for pruning:
• Remove dead, diseased or damaged branches (can be done anytime);
• Maintain/reduce the size of the tree/shrub;
• Stimulate flower or fruit development;
• Rejuvenate old shrubs;
• Prevent damage to life and property from overhanging limbs.
Pruning of ornamental shrubs is of particular interest to home landscapers because you do not want to lose or damage the blooms. You can determine when to prune ornamental shrubs based on when they typically bloom, before or after the end of June.
• If they bloom before the end of June, do NOT prune them now but wait until after they bloom. These shrubs set their buds in the previous fall; if you prune them now, you will be pruning off the buds and not have any blooms this season. Examples: Forsythia, Rhododendron, Azalea, Crabapple, Lilacs.
• If they bloom after the end of June, prune them NOW before grown begins and buds are set. Examples: Aralia, Butterfly Bush, Beautyberry, Clematis.
• Hydrangeas vary based on the species:
o Hydrangea arborescence (Smooth Leaf) – cut to within 6” of ground in late winter/early spring; blooms on new wood, remove spent blooms.
o Hydrangea paniculata (Hardy) – prune late winter/early spring; blooms on new wood, remove spent blooms.
o Hydrangea mycrophylla (Big Leaf) – prune late summer after blooming; new cultivars bloom on old and new wood, remove spent blooms.
o Hydrangea quercifolia (Oakleaf) – prune late winter/early spring only to remove dead wood; blooms on old wood, so prune after blooming, remove spent blooms.
The best time for pruning fruit trees is when they are dormant, February to April. If you are interested in growing fruit, download this guide from Cornell University, ‘Cornell Guide to Growing Fruit at Home’, http://www.gardening.cornell.edu/fruit/homefruit.html.
Pruning tools should be of high quality, sharp and clean:
• Hand pruners are used for cutting branches up to 1/4 inch in diameter; some pruners can cut larger diameters, check the specifications when purchasing your tools.
• Loppers cut up to 1 inch in diameter.
• Pruning saws are necessary for cuts over 1 inch in diameter.
Have your tools sharpened on a regular basis and be sure to clean them in a bleach solution between cuts if pruning a diseased tree/shrub to avoid spreading the disease.
Avoid pruning shrubs in a ‘haircut’ fashion. This encourages growth at the end of the branches reducing air and light throughout the body of the shrub; eventually the inside branches of the shrub will die. Instead, use a ‘thinning’ technique cutting the branches at different lengths ¼ inch above an active bud. Cutting above a bud prevents dieback of the stem and a new branch develops from the bud. Some stems should also be removed at ground level. Also, remove branches that tend to rub against one another.
For more detail information on pruning, download this guide from Cornell University, ‘An Illustrated Guide to Pruning Ornamental Shrubs and Trees’, https://ecommons.cornell.edu/handle/1813/3573