Sometimes it’s OK to trim back juniper in the winter
Happy new year! The thing I’d like to know is if there is a time of year or season that is best for trimming or cutting back mature juniper evergreens? I have some mature (20-plus years) mint julep shrubs and Spartan uprights.
Also, is there a worst time to do it? I have some branches, some big, long ones on the Spartans that have bent over from the weight of the snow that we had in November and December.
Happy new year to you, too!
Generally, you can prune a juniper any time of the year with one exception. I don’t like pruning them in the winter while it’s freezing hard at night.
The thinking is that when you prune them this time of year, you’re exposing growth that’s been deeper “inside” the plant. This interior growth hasn’t been exposed to the rigors of winter weather. It has been shaded and insulated (you would be surprised how much) by the growth on the outside of the plant. The sudden change for this tissue can sometimes result in burning and scorching of the foliage and occasionally even some stem die-back.
What you’re dealing with has happened all over the valley and, in this case, I’d throw my usual recommendation out the window. I think it’s advisable to do some cutting back as soon as possible. The longer those branches are left bent over, the more likely they will stay that way come spring. In fact, I’d guess they’re already at that point since it’s been a good month since those heavy snows.
What this means is that your job is to prune those plants to begin to restore their shape. On branches that have been bent over, you want to cut them back until either the reduced weight allows the branch to more or less spring back to its original position or you want to cut them back to where the branch you leave fits within the rough shape you want to restore of the plant.
This is a bit of a setback to the plant. It’s not really harmful, but it does mean your plants will be smaller and less developed than they were before these snows. They’re going to be more open and maybe even a little misshapen (at least in the short term) than what you had before. Not the end of the world; junipers tend to grow back pretty quickly and I’d guess in a year or two or three you might never know something like this happened.
You may have to do some additional pruning on the plants depending on how they grow in response to what’s happening now and the final look you’re looking for in the plants.
Also, you don’t absolutely have to do this corrective pruning right now. Since they’re probably already set in their new shape, waiting until March probably wouldn’t make that much difference to the plant plus it would be a lot more pleasant for you to be out there pruning on the plant.