Trimming Evergreen Trees

Posted on: 27 July 2019

Certain evergreen trees, particularly varieties of thuja, yews, and junipers, are traditionally pruned to give them a more pleasing shape and to guard against damage and disease. The varieties that require regular pruning have full, cylindrical or rounded shapes, as opposed to the naturally pleasing pyramidal shapes of pines, spruces, and firs. It's important that these trees are trimmed correctly, however, or you be doing more harm than good.

Don't Cut Into Old Wood

Most evergreens, with the exception of some in the yew group, do not produce new leaves or needles on the old wood. If you cut the branch back into the hard old wood that has few to no leaves near the trunk, you will end up with a bald spot. This is because there are no longer meristematic cells in this older wood. These cells are the ones responsible for sending out new growth. The best practice is to check for pruning recommendations for the specific tree so you can make sure to avoid a bald area.

Do Avoid the Flat Top

You may have seen evergreens cut into quirky boxy shapes, but unless you live in climate that doesn't experience snow or ice, this is a huge mistake. The weight of snow and ice on top of a flat topped evergreen can cause it to split, breaking branching and causing irreparable damage. Instead, opt for a rounded top or even a sharp point, since this will allow snow and ice to slide off without causing any damage to the tree.

Don't Try to Control the Size

Pruning is mainly used to keep a tree healthy and to help maintain it's shape. Cutting to control size will backfire and either leave you with bald spots or kill the tree. As a general guideline, never remove more than a third of a branch or a third of the entire canopy. Trying to remove more results in cutting into old wood or worse, removing too many leaves or needles so that the tree can no longer photosynthesize enough to survive.

Do Prune At the Right Time

Pruning too late can cause damage to an evergreen. For most varieties, late winter or early spring, before the new needles begin to come in and unfurl, is the best time to trim. The trees are dormant at this time, so you will not damage any of the growing tips.

For more help, contact a tree trimming service in your area or click here.