During the long, hot dog days of late summer I always notice that I get fewer calls from home gardeners. That was especially true this year. In the searing heat, who wants to go outside and work in the yard?
All of that changes with the arrival of autumn. And, I must confess, the weather as of late has been glorious! The temperature has been moderate and even the leaves are beginning to change. The skies are blue and everything outside is inviting.
The brisk weather is even drawing out the folks who seldom venture outside, just look at those busy sidewalks. Another tell-tale sign of fall is all of the people eagerly enjoying yard work.
You may be noticing about now that some plants have gotten a little "leggy" since the last time you were in the yard. And I’m sure you’re right. Well, since it is a beautiful day for yard work then it is also a good time to do some pruning, right?
Wrong! In spite of our natural inclinations, fall is one of the worst times to prune woody shrubs and trees.
The first reason to avoid fall pruning is because fall-pruned shrubs tend to have more winter injury. Pruning actually encourages new growth in many plants. If you were to take a look at a shrub that was pruned last year, then you will likely notice that two or three new shoots developed just below the pruning cut. The reason for this is because pruning a long branch or shoot stimulates the growth of the lateral buds that had lain dormant on that shoot.
It takes time for the buds that produce those shoots to sprout and it takes even longer for those tender new shoots to grow. If the plant was pruned in the spring then we seldom see problems because generally by the time the buds and shoots develop the weather is usually warm enough to not damage the new growth. However, if we prune in the fall, then we have a different story to tell.
As I mentioned, fall pruning can lead to the development of tender new growth. If those new shoots are exposed to harsh winter temperatures and cold winter winds then those young shoots can either be damaged or killed, leaving a not so happy plant once spring comes around.
Fall pruning can also have an adverse affect on early spring flowering plants. Azaleas, for example, have already set their buds for next year’s flowers. If you prune them now they will not have time to develop a new set of flower buds before next spring. The result is that your azaleas will not flower well. This is true for some types of hydrangeas and many other spring flowering plants as well.
To avoid these problems we have a general rule of thumb for pruning. Shrubs that flower before May (azaleas, etc.) should be pruned immediately after they finish flowering each year. Certainly no later than July 4! Woody plants that flower later than May should be pruned in late February or very early in March. Of course, there are exceptions to these rules so feel free to contact me at the Extension office at 912-876-2133 if you have questions.
Increased winter injury and the negative impact on flowering are two good reasons to avoid heavy fall pruning. There are, however, some reasons to do minor pruning now. Broken limbs, or branches can be removed. If they are left on the plant then they can further problems. For example, further tearing of the bark can create larger wounds that provide openings for disease and decay. Just clip them off just above a side growing shoot.
You can also do minor pruning to remove diseased wood or parts of the plant that have died back due to drought. Just remember, the more you prune now the more you increase the likelihood of winter injury.
So go on, get out of the house and enjoy this fabulous fall weather. If you see a broken branch, sure, clip it out – just don’t get carried away with those pruners! Fall is not the time to do heavy pruning in the landscape. Instead, get ready to use some of that energy installing new plants and raking leaves. Don’t forget to toss those leaves in your compost so you will have free soil amendments for your spring flowers.
That’s all for now, thanks and happy fall gardening.