Pruning pines and other evergreen trees
This week’s final article on pruning focuses on evergreen trees. There is a big difference in timing the pruning of pines versus spruces and others. Pruning pines at the wrong time means no more growth on that branch.
Spruces, hemlocks, and firs are all evergreens having buds up and down their stems. Pines, on the other hand, only have buds at the terminal ends of the stems and branches.
Pruning pines is accomplished when the terminal buds begin to break or elongate and after they are fully elongated, but before they harden off in mid-july. This time frame is usually late May to mid-july.
If you have a pine tree, look at a branch and find the terminal bud. You will notice no other buds on this section of the branch. There will be lateral branches with terminal buds, but again, these lateral branches don’t have buds on them.
If you remove the terminal bud, this branch or stem won’t keep growing. The lateral stems will continue to grow in the direction they are facing.
If you are limbing up (removing lower branches) in order to mow around a pine tree, this can be accomplished at any time. You are removing an entire limb and therefore aren’t worried about additional growth.
For the most part, pines can be left alone to grow naturally. However, if you have a mugho pine that you would like to keep compact, pruning is beneficial.
Christmas tree growers must prune their pines yearly in order to keep them nice and full of lots of branches to hold ornaments. Pines growing in the landscape can be left alone to grow with a more open habit.
When the terminal buds on a pine elongate and are nice and tender, you can cut them with sharp pruners or even pinch them with your fingers. Of course, your fingers will end up nice and sticky from the sap!
The other evergreens mentioned have buds up and down the stems and can be pruned at almost any time. I tend to prune some of them in December to use for holiday decorations.
The other time I prefer to prune is right before new growth begins in the spring.
When pruning, make sure you cut back to a bud for the best results. You can control the direction of the new growth by cutting to a bud that is facing the direction that you want the branch to grow.
This technique, directional pruning, can be used for any plant. Cutting back just before a bud that is outward facing prevents branches from growing in the center of the plant and results in better air circulation.
In terms of pruning a pine tree, you won’t kill it if you prune now, just make sure you don’t need the branch or stem that you are pruning. I take that back, if you use basal (cutting at the base of the plant) pruning, you will kill it!
Pamela Corle-bennett is the state master gardener volunteer coordinator and horticulture educator for Ohio State University Extension. Contact her by email at email@example.com.