Hey, it sure is comfortable out working in the garden in late summer. There’s some harvesting to be done while the weather gets a little cooler. But there are also things to put off for a while. Mainly pruning, which is certainly a tempting thing to do. After all, we’re already cleaning out all of the debris that’s accumulated over the months. We’re getting rid of damaged and dead stems–and isn’t that what you always do right before pruning? Why pruning in late summer is not always a good thing.
Resist your urge to prune
You should still resist that urge to actually start pruning. There are plenty of pitfalls to doing that kind of thing in late summer. Consider all of those early-spring bloomers like rhododendron and lilac. Those should’ve been pruned after they finished blooming in late spring. Doing them now (or into winter) means that you can lose future spring blooms by cutting away flower buds. Same goes for hydrangea types. There are a few re-blooming types that can still bloom on new growths, but why take the risk?
What can be pruned in late summer?
If you really feel compelled to do some pruning in late summer, then you can try cutting back shrubs like barberry. We don’t recommend it once you’re into late fall, but there’s no reason not to do some cleaning up now. Once you’re late into autumn, though, you really want to give that new growth a chance to harden. Then you can cut the shrub back once it’s gone into winter dormancy.
Pruning in late summer: flowers
Same goes for summer flowers like butterfly bush, potentilla, and crape myrtle. Leave the prune shade trees alone for now, though. Those are also best left to when they go dormant in winter. You can judge the structure of the branches better then. You also decrease the chances of spreading disease.
Why wait until fall to prune?
The best reason not to prune in late summer, however, is that you’re at risk of stimulating new growth. Those tender shoots aren’t going to be ready when winter comes along. Then you get some damage that will require more pruning in spring. And that’s just more work, and you’ll feel plenty bad about it, too. So take some time off sitting on the front porch. Take in the cooling breeze and enjoy a few hours of not pruning. Your garden will thank you later.