The start of fall gets many gardeners stoked about tree trimming. There’s something about changing leaves that just makes a little pruning seem right, but don’t reach for the shears just yet. When it comes to tree trimming, hacking away during fall can do more harm than good.
Problems With Fall Pruning
The biggest reason to avoid trimming trees in fall is that trees are most susceptible to diseases at this time. Wounds on trees heal slowly during the autumn months. Decay fungi also spread spores profusely in fall, and these two factors can spell major trouble for recently trimmed trees.
If you absolutely must prune your trees in fall, wait until the leaves have all dropped and the trees have gone dormant — usually late October to early November, depending on your climate.
So When Should I Trim Trees?
Late winter to early spring is the most common time for tree trimming, and summer pruning is also a possibility. Which time you choose depends on your reasons for trimming.
- Winter Pruning: Trimming trees during the dormant season results in an explosion of new growth the following spring, so winter the best time if this is the goal you have in mind. It’s best to wait until after the coldest part of winter has passed, but always trim trees before new buds begin to form.
- Summer Pruning: Trimming trees during summer has the opposite effect, stunting or dwarfing the development of a tree or branch. Trim trees during the summer months (after new leaf growth has stopped for the season) if you want to reduce the size of a tree or manage its shape.
Flowering Trees and Shrubs
Pruning to increase blooming on flowering trees and shrubs is another matter altogether. For trees that bloom in spring, take care of trimming after the flowers fade. For summer bloomers, trim in winter to early spring.