Many seek tips regarding how to prune arborvitae, whether generally — or specifically — after a shrub has suffered branch damage in winter due to the build-up of snow and/or ice. Should you cut branches that are bent from the top and, if so, how? Will lower branches fill in if they are pruned?
How to Prune Arborvitae
Arborvitae is sometimes pruned so as to grow with a single leader, in which case extraneous leaders are pruned off entirely (right back to the trunk). If your arborvitae is young, it may not be too late to train it in this fashion. The ice or snow damage caused some leader branches to become "bent from the top" on your arborvitae, so this gives you an opportunity to assess your "leader situation."
While we never enjoy seeing such damage, there could be a silver lining. The damage provides you with just the excuse you need to target these bent branches as extraneous leaders and trim them off, leaving in place only the straightest leader.
If however, your arborvitae shrubs are already several years old (or if all the potential leaders have already become bent due to shouldering excessive snow and ice), it is too late for such pruning. You could, however, try to straighten them out by tying branches together with strips of cotton fabric (perhaps in conjunction with staking).
Tips on Pruning Branches
- Do not prune back further than where you see stems with green foliage (unless you can live with not having a branch there at all, in which case you would prune right back to the trunk).
- Bare arborvitae branches will not sprout new growth.
The best time for pruning arborvitae shrubs, generally speaking, is late winter or early spring. If you are using them in a hedge, you will perhaps want to shear them in late spring or early summer as well (keep the top of the hedge narrower than the bottom, so that the lower branches receive sufficient sunlight).
As for the "ones that took a beating overall," remove them and start with fresh, appropriately-sized arborvitae stock. Rejuvenation pruning (whereby plants are pruned almost to the ground, in hope that they will come back anew) is not an option here, as it is for some deciduous shrubs. Even in the case of shrubs responsive to rejuvenation pruning (such as lilacs) your planting will be out of balance for years with relatively tall plants (the ones you left alone, more or less) intermixed with the ones drastically hacked back. Therefore, growing new plant trees and shrubs is favorable.
Does It Help a Damaged Shrub to Fertilize It?
Some gardeners wonder, "The following spring, should I be fertilizing plants damaged in winter to help them recover?"
Fertilizing is generally not recommended as a way to help damaged shrubs recover. Fertilizer is most productive when a tree or shrub is healthy enough to absorb it properly; that is, fertilization is more about “feeding” (or helping a plant take up nutrients more effectively) than “healing.”
You need to allow your damaged arborvitae shrub some time to heal. Wait until you see the injured plant leafing out (signifying a return to health) before fertilizing.
In the meantime, check the wounds to make sure no fungi are exploiting it in its weakened condition.