Canadian County OSU Extension Service

Proper Pruning

I know that many of you have suffered the loss of important trees and shrubs over the past few months, in part due to the amount of ice and the species of tree, but in some cases improper pruning was a factor.

Proper pruning is an important practice to ensure tree health and strength during challenging weather.

Pruning can actually be done at any time of the year as we have seen over the last few months due to the ice damage. In many cases though, the best time to prune is during late winter or early spring just before growth begins and the least desirable time is immediately after new growth develops in the spring. How­ever, recommended times do vary according to the type of plants.

When you are pruning flowering plants, it is important to recognize the time of year it blooms, as this can be a clue of when to prune the plant. 

The blossom of summer-flowering shrubs, trees, and vines bloom on limbs grown in the same season as the flowers. This new growth is known as “new wood”. This category of plants includes glossy abelia, butterfly bush, and rose-of-Sharon. These plants may be pruned in the fall or in early spring and will then develop new wood with flower buds in the spring and summer. 

In contrast, spring-flowering trees, shrubs, and vines bloom earlier. Therefore their flower buds are already present on the previous year’s growth or “old wood”. 

If you prune these plants in the months prior to their spring blooming period you will be removing the flower buds. This would inhibit a floral display, which is often the main reason for growing the plants in this category such as crabapple, flowering quince, forsythia, viburnum, and wisteria. 

In order to maintain the structure and enjoy their flowers, these plants should be pruned as soon as the flowers have faded in late spring. They will then have the remaining time to recover and produce to new growth and flower buds for the following year. 

Contrary to popular belief, pruning at the wrong time of the year does not necessarily kill plants, but continual improper pruning results in damaged or weakened plants. Therefore, do not prune at your convenience, but rather when it results in the least damage to the plant.

For information on how to prune your ornamental trees, shrubs, and vines, read the OSU factsheet HLA 6409 which is available on our website

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