Deciduous shrubs are woody plants that drop their leaves in autumn. Examples of deciduous shrubs are lilac, forsythia, snowball viburnum, and cranberry cotoneaster. Deciduous shrubs are valued in the landscape for their foliage, branching characteristics, fall leaf color, flowers or colored twigs in winter. Some shrubs have colorful fruit that attracts birds. Selection of deciduous shrubs should be based on their function in the landscape. Shrubs have different habits of growth, fast, medium or slow, with upright, wide-spreading, arching or horizontal branching. The proper selection of the right plant for height and spread at maturity can reduce the need for pruning.

Why Prune?

Before you start to prune, know what you wish to accomplish. Pruning is one of the essential but least understood of the garden maintenance practices. Good pruning is the selective removal of branches without changing the plant's natural appearance or habit of growth. Shrubs trimmed to an artificial size or shape require more pruning than shrubs pruned to keep their natural shape. Prune to improve the health of the shrub by cutting out dead, diseased, broken and overgrown branches that interfere with new growth. Prune to control the shrub's size, shape, flower, fruit and colored twig effect.

How to Prune:

Three methods used to prune a shrub for a specific purpose are thinning-out, renewal or rejuvenation and heading back or shearing. By thinning out, a branch or twig is cut off at its point of origin from the parent stem, to a lateral side branch, to a "Y" of a branch junction or at the ground level. This method of pruning results in a more open plant and does not stimulate excessive new growth. Considerable growth can be cut off without changing the plant's natural appearance or habit of growth. Plants can be maintained at a given height and spread for years by thinning out. This method of pruning is best done with hand pruning shears, not hedge shears. Thinning allows room for growth of side branches. Thin out the oldest and tallest stems first.

By renewal pruning, the oldest branches are gradually removed from an overgrown shrub at the ground level. It is best to do this over a three-year or longer period, leaving the younger more vigorous branches. New shoots that develop can be cut back to various lengths by the thinning method to develop into strong branches.

Heading back or shearing refers to cutting back a branch anywhere along the length of a stem. The cut may be above a bud, below a bud, or it may even leave a stub. The effect of heading back or shearing is to concentrate vigorous upright new growth below the cut. This method of pruning is frequently done with hedge shears without regard for the natural form or branching of the plants. If every branch or twig is headed back, more growth develops than was removed by the pruning. The natural form of the plant is altered by the extra growth. Hedges are pruned to a definite size or shape with hedge shears.

Avoid leaving stubs when pruning even a small shoot or twig. Short stubs will not heal over properly and will eventually provide a source of entry for insects and diseases. Cuts too far above a bud may destroy the bud by decay or die-back. Cuts too close to the bud may dry out the bud, especially in winter. The proper pruning cut should be 1/8 to 3/8 of an inch above the bud, slightly slanted away from the bud.

When to Prune:

The ideal time to prune most plants is during the dormant season prior to the start of new growth. Flowering shrubs may be an exception. Shrubs that bloom in spring may be pruned after flowering. Late flowering shrubs that bloom on wood produced the same year can be pruned before growth starts in the spring.

Some landscape horticulturists believe the effect of the shrub's structural branching characteristics is more important than its flowering effect in the total landscape design. Therefore, it may be better to prune all flowering shrubs in early spring before new growth starts. Some bloom will be sacrificed by this method. Either method can be recommended. One has to determine for himself the time to prune deciduous shrubs.

Pruning Tools:

Pruning shears -- for branches 1/2 to 3/4 inches in diameter. Twisting shears to cut larger branches will strain and weaken them. The anvil-type of pruning shears is satisfactory for general pruning. However, the scissors or draw-cut type hand shear is preferred for close-cut precision pruning. Lopping shears -- have long handles and are designed to cut larger branches 3/4 to 2 inches in diameter. Pruning saws -- have narrow blades, coarse teeth and are designed to cut on the pull stroke. Small curved pruning saws are useful to prune larger shrubs. Hedge shears -- are used for shearing hedges or formal-shaped plants. Avoid using hedge shears for other pruning purposes.

Adapted from Fred K. Buscher, Ohio State University, 2000