When Pruning Trees and Shrubs, Timing Is Everything

Pruning is always a question for many gardeners, when and how to prune are the most common. It really depends on what you are pruning. For trees and shrubs pruning is a way to help rejuvenate and stimulate new growth. But there is a right time and a wrong time to prune.

Here are a few general rules you need to know before you pick up your pruning shears this spring.

For many trees and shrubs timing is key, especially when pruning spring flowering shrubs. Plants like Azalea, Forsythia, and lilac bloom on the previous years growth. Flower buds are produced the previous growing season and overwinter on the plant. Pruning these shrubs in the fall or winter will prohibit flowering in the spring. Many of these shrubs benefit from light pruning to keep the natural shape of the plant. You want to avoid over pruning or shearing too closely. This practice alters the natural growth structure of the plant resulting in unhealthy looking plants that will flower very little.

Trees and shrubs flowering in the summer should be pruned in late winter or early spring. These plants flower on the the same years growth and are fast growing, like Buddleia and Caryopteris. Roses, Hybrid tea and floribunda should also be pruned in early spring, just before plant breaks dormancy. Shrub and Knockout roses can benefit from this as well. Fruit trees, evergreens, Viburnum, Crepe Myrtle and Rose of Sharon can also be pruned in the early spring.

Pruning hydrangeas on the other hand can be tricky. Hydrangea paniculata and arborescens, flower on the new seasons growth. Pruning in the late winter or early spring is ideal. Hydrangea macrophylla flower from the previous years growth. Many of the new breeds and varieties of hydrangeas bloom from old and new wood, like the endless summer series. It is best to cut back in the late summer. If your plant has become too large or if you are cutting blooms for floral arrangements be careful not to over prune, this can result in fewer blooms the following year.

Pruning tips:

1. Use sharp shears that are cleaned and sanitized to avoid spreading any disease.

2. Remove diseased wood immediately.

3. Make cuts at an angle and close to the collar of the tree. This will keep insects out that can carry disease and harm the tree.

4. Remove crossing branches. Always cut off the smaller branch.

5. Remove thin and spindly looking branches. This helps to thin out the tree or shrub, opening it up for more light and wind to pass through.

6. Remove suckers growing from the trunk of tree.

7. Cut shoots growing straight up towards the center of the tree from thebark or on branches.

8. Avoid pruning in fall. Plants are still growing in the fall. Pruning stimulates growth in plants who are otherwise winding down their growing season and preparing for dormancy. Freezing temps can injure plants pushing new growth.