Some Final Words On Proper Pruning
For the past couple of weeks I’ve tried to give you the short course on pruning. We learned a bit about the makeup of a tree, a bit of pruning terminology, what tools we need and which branches to remove.
Now, I’ll try to address a few of your specific concerns on the subject.
When do we prune flowering trees and shrubs? There are two types of flowering plants, those that bloom in the spring — forsythia, lilac, dogwood, etc. — and those that bloom in summer — butterfly bush, clematis and potentilla, for example.
Plants that bloom in the spring, have already set their flower buds on last year’s wood. If you look closely, you’ll see the fat buds just waiting to burst open. If we prune now, we run the risk of removing the flowers.
However, now seems like such a perfect time to prune - with the leaves off the tree we can easily see the branches we want to remove. Here’s an idea: Now, while the tree is leafless, use white latex spray paint to mark each branch that you wish to remove. Later when the plant is finished blooming and totally leafed out, you can easily make the cuts where you made the white marks.
The idea that we can’t prune spring-flowering plants now is also a bit exaggerated. Of course we can prune them. If proper thinning cut are made, we’ll lose some flowers, but not all.
Summer-flowering plants produce their flowers on brand new wood - stems that are produced this year. In view of that, the more new wood we can stimulate through pruning now, the more flowers we should have on the plant this summer.
When is the best time to prune maple trees? Maples can be pruned just about any time of year.
However, trees like hornbeam, birch, walnut and maple tend to ooze great amounts of sap from their wounds if pruned while actively growing. This sap does not hurt the trees, though. It will usually stop some time in June. The only tree out of this group that we shouldn’t prune now is the birch. The running sap may attract bronze birch bore, which can enter the tree and eventually kill it. The sap can also discolor the white bark. Birch trees should be pruned in the fall as the leaves begin to turn yellow.
Will painting over the pruning cuts stop the dripping? No. If the wound is large, the tree will drip until the tree seals off the cut. In fact, pruning paints are no longer recommended. Research has shown that painting over pruning cuts may trap harmful bacteria, thus causing disease. Pruning cuts seal faster if we leave them alone. The only time a pruning paint may be advised is when pruning is done at the time of year when specific insects may transmit diseases or bore into the trees.
When is the best time to prune for controlling tree growth? Think of it this way: The leaves on the tree produce energy which is stored in the root system. This stored energy is waiting patiently to produce new leaves come spring. When we remove branches during the dormant season, we remove areas for leaf development. All that stored-up energy has to go somewhere, and the somewhere is usually in the form of strong shoot growth.
If we prune during summer we take away some of the energy-producing leaves. When the tree goes into dormancy, there is less energy to store, thus less shoot development in the spring.
To make a long story short, to control growth, the best time to prune is late summer. Of course, we’re dealing with nature. Like the pruning pictures in the pruning manual - it may look good on paper, but it’s seldom like the real thing.
Remember, we don’t top trees. And finally, there’s a saying - “the third time’s a charm.”
Special note: I will be at the Home and Yard Show at the Interstate Fairgrounds this weekend. Please drop by with your gardening questions or just come by and say “Hi.” I would love to meet you.