Question of the Week Number 3: December 6, 2018
Dear Neil: When can I prune my shrubs? Several have grown way too large. And how far back can I cut them?
As for when you can prune…
There are several possible answers:
• Shrubs that are completely winter-hardy in your locale can be pruned now. It’s best to remove branches one at a time as you strive to retain a natural growth form with them. Avoid power tools that leave them looking like the barber fell asleep during the haircut.
• Plants that are known to be somewhat tender to your local winters ought to be saved a few weeks. In the off chance that they suffer freeze damage this year, you’ll want to be able to reshape them. Wait until late January or early February to prune them.
• Plants that are consistently too tall or too wide for their surroundings perhaps should be dug and relocated or removed entirely. Pruning will only buy you more time, at which point you’ll have it all to do over again. Eventually you’ll end up with a shrub that’s been dwarfed by all the repeated pruning – but it will have a huge trunk. Take it out and choose a plant that stays small in its place.
As for how much you can trim them…
That depends on your expectations and their vigor. If you’re trying to keep a 12-foot shrub beneath low windows, say at 3 feet in height, you’re setting yourself up for failure.
But if you’d be content to remove 25 or 30 percent of a shrub’s height or width, reshaping it in the process, that would usually be absolutely doable. However, if you find yourself repeating the task year after year, as I just mentioned, you’re probably going to wear down the plant’s vigor to a point that you’ll eventually just want to replace it.
So perhaps you’ve noticed that there are no absolute rules in how you should prune the plants at your place. But hopefully these general guidelines will help you get started.