Pruning Deciduous Trees and Shrubs

Deciduous trees and shrubs are simply those that shed their leaves at the end of each growing season, as opposed to evergreens that keep their foliage year around. As with all plants, you should have a plan before doing any pruning. Good reasons to prune would be to remove damaged or dead branches, to shape young trees and shrubs or to thin excessive growth. For pruning purposes, deciduous plants are divided into blooming and non-blooming.

Is there an overall rule of pruning non-blooming deciduous plants?

Generally, the best time to prune anything deciduous is just before new growth (in late winter or early spring) when the leaves emerge. The worst possible time to prune is right after everything leafs out, since the plants have just used up most of their stored energy and haven’t had time to replace it. Fall used to be thought of as a good time to prune deciduous material, but spring really is better if possible. Plants store lots of energy in twiggy growth to help them winter, and cuts will heal more quickly when the plant is getting ready to grow as opposed to shutting down.

When do I prune blooming deciduous plants?

If a deciduous plant blooms very early in the spring, such as lilacs and old-fashioned Bridalwreath spirea, it is blooming on last year’s growth and should be pruned right after it blooms. There are a few plants, such as weigela, that bloom on old wood but bloom later in the season. They can be pruned lightly in spring or after they have bloomed. Another large group of blooming deciduous plants form their flowers on the current season’s new growth, such as potentilla and the low, mound-type spireas. These plants are best pruned in early spring before they leaf out. Would it hurt these blooming plants to prune them at the wrong time?
Generally, the only adverse effect will be that you may lose the blooms. You may want to consider letting the pruning wait until next season, but sometimes we just don’t have a choice and have to prune when we can.

What about deciduous hedges?

Formal hedges can usually be pruned lightly in late spring and again in mid-summer to keep them uniform in appearance. Often, lilacs and other blooming shrubs are used for informal hedging, and they should be pruned at their appropriate time to preserve their blooms.

Should I prune a newly planted tree or shrub?

When you are buying from a reputable nursery, your new plant material will already be properly pruned. Other than removing any damaged branches, do not prune aplant until it has been in the ground a full growing season.

How should I prune bare root plants?

Recent research has changed how we prune bare root plants. It used to be common practice to prune the tops of new bare root stock, thinking this would give them less to support as they reestablished their root systems. We now understand that bare root plants need all their buds to provide leaves for gathering energy to grow. These plants were probably properly trimmed as they were grown, so they shouldn’t need much, if anything. When you are planting bare root plants, simply remove any damaged branches and roots and wait until the next growing season to do anything further.

Should I seal the wounds when I prune?

Sealing wounds with pruning paint is another common practice that has fallen out of favor. We now know that in most cases, clean, unsealed wounds will heal more quickly and with less disease and decay than will those covered with pruning paint. Unless you are dealing with trees and shrubs that are known to be susceptible to disease transmission through wounds, do not seal the wound What varieties of trees and shrubs should be sealed? Special care needs to be taken to try to minimize transmission of Dutch Elm, Oak Wilt and Fireblight disease. These diseases can be deadly and often enter plants through fresh wounds. They are spread from one tree to another most often by insects. To be safe, avoid all pruning and seal all injuries to susceptible trees during the growing season. American Elms are susceptible to Dutch Elm disease. All Oaks are susceptible to Oak Wilt disease. Fireblight most commonly affects Mountain Ash and several varieties of fruit trees.

Are there any special tools for pruning deciduous trees and shrubs?

All you will need is a good pair of hand pruners. For larger cuts, you can choose from loppers (long-handled pruners) and pruning saws. Both pruners and saws are also available on a long-reaching pole. If you are going to do a lot of pruning, it will pay to buy the best quality you can afford. Almost all pruners are easy to use at first, but the better tools will be just as easy to use when you make the last cuts. The best hand pruners are bypass pruners, with blades that pass by each other, like a scissors, making a good, clean cut. When using pruners, make sure the cutting blade is on the upper side of your branch and the holding blade is below. If you need to prune out large branches or prune well beyond your reach, consider calling a professional