Winter vs. Summer Pruning (and Is Aggressive Good?)

It’s satisfying to see trees in the spring that were pruned in winter. It’s more satisfying if you’re the one who did the pruning. There are also many benefits to winter pruning. Because the tree is dormant, winter pruning doesn’t stimulate new growth. In contrast, any pruning done just before dormancy (such as during late fall) can then be negatively affected by cold weather and may damage the tree.

Research shows that pruning before buds open in spring leads to “optimum wound closure.” Trees are able to heal from pruning cuts before warmer weather brings out destructive insects and pathogens. I get asked often if we’re able to prune for deadwood in the winter because it’s harder to tell the difference between what’s dead and what isn’t. It’s true that without the foliage it can sometimes be difficult to spot dead branches. However, a trained arborist that knows what to look for will seldom have a problem. Also, it’s easier to see branch structure and spot what could be future issues like competing or rubbing limbs.

Should I avoid pruning during the active growth season?

So, while winter is a great time to prune, that doesn’t mean that spring and summer pruning is bad for your trees. It simply offers different benefits and is done for different reasons, such as:

•Removing deadwood that may be hard to spot in winter

•Removing damaged or diseased branches that could be dangerous

•Elevating or raising the canopy to improve a view

•Improving canopy structure and shape

I tend to feel that for live growth, less is usually better, especially in the summer, to avoid sun-scald.

How about aggressively pruning a tree? 

I think most arborists would agree that aggressively pruning a tree, while it may be needed for safety purposes, is never good for the health of a tree any time of year. But sometimes it can be difficult to understand what is aggressive and what isn’t. A feeling I’ve always had is that a good arborist can effectively prune a tree in such a way that it’s hard to tell if it’s even been pruned at all. In other words, the goal is met and the tree continues to look natural. If you can look into your pruned tree and think, wow, that’s a lot of pruning or, those are some big cuts! then it probably wasn’t done with the health of the tree in mind. If nothing else, aggressive pruning just looks bad!

As always, my advice remains that if you’re unsure what needs to be done, don’t do anything at all and call an arborist.