Which plants should I prune now and how?

Pruning your trees and shrubs in the winter is both art and science.

Some of the most important reasons for pruning are to train the growth of plants into a particular form for a specified space or to encourage new growth and vitality for the next blooming season.

As a general rule, plants that flower before May should be pruned after they bloom, while those that flower after May (summer bloomers) can be pruned prior to spring growth. The oakleaf hydrangea and late flowering azalea cultivars are exceptions.

In January, before new growth begins, prune plants that bloom on branches produced during the current growing season. These plants include abelia, beautyberry, butterfly bush, most hydrangeas, gardenia and crape myrtle.

Wait until May or after to prune shrubs such as azaleas, rhododendron and viburnum.

Flowering trees should be pruned and trained while they are young. Flowering trees and trees that lose their leaves in the winter should have one central trunk and at least five to eight strong lateral branches along the main trunk.

Major limbs should begin around 5 feet above the ground and have good spacing. Once the major framework of the tree is established, annual maintenance is required. Each tree is different in growth habit and vigor.

Some general considerations will help in pruning decisions.

• Any major limb that develops into less than a 45 degree angle is likely to develop a weak crotch and may split. Remove these limbs.
• Remove any branches that grow inward or rub against strong branches.
• Remove any upright shoots that compete with the main trunk for dominance. This also will enhance the attractiveness of the tree.
• Never top off a tree. This pruning technique will destroy the branching control and shape of the tree.
• Broadleaf evergreen trees, like magnolias and hollies usually require little or no pruning. They have a natural symmetric growth habit when left alone.
• Conifers do not require any pruning, unless you are pruning out dead or diseased limbs.

Most people approach pruning with a great deal of anxiety. With proper pruning techniques and some advice from your local Extension office, the gardener can gain a basic understanding and even master the art of pruning.

Wanda Cannon is a Master Gardener trained through the Hall County program and also serves as Master Gardener coordinator and horticulture assistant for the Hall County Extension office. Phone: 770-535-8293.