How To Prune

Careful pruning results in healthier and stronger plants, sturdier growth, more abundant fruits and larger blooms. Pruning controls the shape, size and symmetry of plantings. These are the essential reasons for pruning.

Healthier Plants – It’s a drain on the energy of any plant to support dead, broken or diseased branches. They should be cut off as soon as noticed. Dead wood gives insects and plant diseases an easy place to attack, endangering the entire plant.

Control Growth – Pruning for growth means giving a young plant a basic structure of good habits and tendencies.

Bloom and Fruit – Blossoms that increase in size and quantity are usually the result of proper balance between the foliage and the roots. Bare woody stems, where blooms are sparse can be removed safely with proper handling.

To Shape and Form – There are two types of pruning for shape and form. The first is in formal foundation plantings where the shrubs are sheared to fit a particular landscape design. The second is limited control for the health of the plant, to retain the plant’s own natural form and outline.

Pruning at Planting Time – A growing tree, shrub or plant usually has balance between the roots and the plant growth above it. In transplanting, digging disturbs part of the root growth and some of it is destroyed. Consequently, when planting bare rooted trees, the branches should be pruned back and broken or ragged ends of roots removed to restore balance before planting. Trees with an intact root ball in plastic or burlap may need some pruning of excess branches that will not be part of the permanent tree, but not as much as bare rooted stock. Container grown trees require little or no pruning.

Pruning Principles

Plant Growth - New growth on a plant develops from buds formed at the tip of the stems and branches called terminal buds. From these terminal buds the strongest new growth is made. When the terminal bud is cut off, the side buds below receive more energy and grow more vigorously. Conversely, taking off the side buds directs more strength and energy to the terminal bud on the tip of the branch. The buds left to grow determine the shape and form that new growth will take as well as the quality of bloom and yield.

Where to Cut - In its simplest form, pruning is selectively cutting off parts of the woody branches of a plant for a specific purpose. It is usually done when the plant is dormant, unlike “shearing” which is usually done when the plants are actively growing. An important step in pruning is to decide where and how to make the actual cut. Any cut must be clean and smooth so that new bark will grow over the wound. This is a long process if the cut is jagged and the bark becomes bruised. It is very important when pruning to look for healthy buds and make your cut just beyond a bud where you want new growth to begin. Cut no more than 1/4 inch beyond the bud or you will leave a stub that will die back, leaving the plant vulnerable to insects and diseases.

Make the cut just above a bud that points in the direction where new growth is desired and at a gentle angle behind the bud as shown in illustration (A). A cut made at too steep an angle (B) exposes an unnecessary amount of wound tissue, as at (C) leaves too long a stub. (D) is too close to the bud which will probable die. A properly slanted cut leaves less stub and dries faster after a rain. Be careful not prune next to inside facing buds, or crossing branches can result.

Generally, larger branches are cut back to a live, main branch of the trunk. At the base of the branch where it meets the trunk will be slightly swelled area, sometimes wrinkled, called the branch collar. Cells in this area form the tree’s defensive zone, where a boundary is formed to prevent damage by insects or disease. These cells will eventually form the wound wood that covers and protects the area from which the branch was removed. Pruning a branch by cutting it flush with the trunk will actually cause further damage since the protective collar area is removed. The key is to look for the distinctive bulge at the base of the branch and make your last cut next to it no matter how large or small the branch being pruned.

In sawing off a sizeable limb, make a three step cut to prevent the weight of the limb from falling prematurely and stripping the bark. The first cut is made about one third of the way through the branch, 6 to 10 inches out from the main trunk and from the bottom up. A second cut is made completely through the branch an inch farther out from the top down. The third and final cut of the remaining stub is then made with one smooth cut from the top down just outside the branch collar. Very large limbs should first be reduced in size by removing outer sections. For the quickest healing results, the wood should be cut clean, with no ragged edges. Large limbs are hazardous and it is advisable to have a professional arborist or tree surgeon do the job.

Shearing - removes all of the new growth along with the terminal buds. This directs strength to the side buds, thus increasing side growth for a denser, bushy hedge. Shearing is usually restricted to removing soft, first-year growth that is easy to cut.

It is best to shear shortly after new growth begins in the spring so that the lateral buds will have all season to grow and make the hedge bushy.

When to Prune - The proper time to prune is variable. Most shrubs, trees and vines are pruned while dormant, just before the sap starts to flow. Pruning at this time results in quicker healing of the wounds as new growth is about to start. There are many exceptions, such as flowering shrubs which should not be pruned until after blossoming or shade trees where heavy spring sap flows will be lost through fresh pruning cuts. Dead, damaged or broken limbs should be pruned any time noticed.

Late Winter - This is the dormant period in most parts of the country depending on where you live, this may be late January, February or early March. Fruit trees, broad-leafed evergreens, vines and some types of roses and shrubs should be pruned while dormant. Once the buds turn green and start to grow it is usually too late for dormant pruning and you should wait until next year for all but light pruning.

Early Summer - As they begin to grow, shear evergreens and hedges. They grow fastest at this time and will produce strong side growth. Do not forget to prune early-blooming shrubs after the last flowers fade.

Late Summer - Certain shade trees should be pruned at this time, such a maples and birches, which will lose too much sap if pruned in spring. The correct times to prune can vary by region. If you are unsure, contact your local Agricultural Extension Service for information on your area.