HO-4
Life Science Library
Pruning Ornamental Trees and Shrubs
HOME YARD & GARDEN • COOPERATIVE EXTENSION SERVICE DEPARTMENT OF HORTICULTURE • PURDUE UNIVERSITY WEST LAFAYETTE, IN
Michael Dana and Philip Carpenter *
Correct pruning is an essential maintenance practice for trees and shrubs in the home landscape. However, most homeowners regard pruning with considerable, though unnecessary, apprehension. Pruning is not difficult if you understand the basics, learn why, when, and how to prune.
Trees and shrubs should be examined annually for pruning requirements. Too often, pruning is ignored for several years. Then some trees and most shrubs become overgrown and often weak, making drastic pruning a necessity to bring the plant back to usefulness. Regular pruning will help keep the plant in bounds and keep its growth vigorous. To prune successfully, you must 1) know why you are pruning, 2) be correct in your timing, and 3) follow proper techniques using proper tools: why, when, and how.
Reasons to Prune
Pruning is necessary to maintain a healthy vigorous tree or shrub. Specifically, pruning is practiced to:
Maintain or reduce plant size. Pruning can prevent a plant from overgrowing its space in the landscape and eliminates the need for drastic cutting of crowded, overgrown plants. It can allow for growth of plants under or adjacent to the pruned plant. It can also serve to reduce leaf area on newly planted trees and shrubs. This promotes survival through transplanting and consequent root loss.
Remove undesirable growth. Pruning can encourage plant vigor through the removal of weak, overcrowded growth. Such thinning often improves the visual balance or symmetry of the plant.
Remove dead, diseased, or broken branches. Pruning will aid in maintaining the shape, vigor, and health of the plant.
Stimulate flowering and fruiting. Removal of the current year's old, faded flowers and fruit clusters will promote flower buds for the following season.
Rejuvenate and restore old plants to vigorous growth. Proper pruning can restore a youthful, natural growth habit in certain overgrown shrubs.
Prevent damage to life and property. Pruning can minimize the hazard of limbs interfering with power lines or overgrowing structures. It can also remove weak crotches before limbs break in strong winds and open blocked sight lines caused by overhanging limbs at driveways or street corners.
Shape plants in an artificial form. Pruning and shearing can be used to shape plants as hedges or for rigidly formal espaliers or topiaries.
Myths about Pruning
There are a number of myths and misconceptions about pruning which should be laid to rest.
Pruning is difficult. Pruning is straightforward if one knows a little about how the plant grows and what it should look like when the process is complete.
Plants will die if pruned at the wrong time of year. Plants may be injured, but seldom, if ever, are they killed by poorly timed pruning.
All pruning must be done during the winter. Actually many plants are best pruned during the growing season.
Topping shade trees will keep the trees from causing damage to the home. Shoots which grow after topping are weaker than the original limbs. They will be more likely to split off and cause damage unless they are removed every few years. Also, wood rots are more likely to be a problem in topped trees, resulting in poorer tree health and greater likelihood of limb breakage.
Removing a tree is a crime against nature. If a
plant is in the wrong place, from a functional or aesthetic viewpoint, it is by definition a weed and can be removed. This is especially true when a tree must be mutilated beyond recognition to eliminate the problem it is causing.
Most trees need pruning. Actually, mature trees seldom do. Young trees usually benefit because pruning helps in establishing the basic branch structure and in overcoming transplanting shock.
‘Acknowledgement is made of M L Witt, R. E. McNiei, W L Mesner. W. M. Fountain, and W. D. Dunwell. University of Kentucky, and G. L. Klingaman, University of Arkansas, whose publications contributed to the current revision.