Start pruning now to get a jump start on spring.

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Master Gardeners often get questions about how and when to prune correctly — and we also get questions about how to “fix” shrubs when pruning has gone wrong.

The first piece of advice is to reduce the need for pruning by selecting the right plant for the right place, including the appropriate cultivar.

For example, crape myrtles range from ‘Natchez,’ which grows 30 feet tall, to the dwarf cultivars marketed as Razzle Dazzle®, which stay under four feet tall.

Keep in mind that plants have two natural responses to pruning: healing and new growth. When a plant loses its leaves, it forms a callus on the outside, walls off damaged tissue from healthy wood on the inside, and grows more leaves to provide nutrients for the plant.

If the terminal (i.e., end) buds on the tip of a shoot are cut, the lateral bud next in line directs the speed and direction of new growth. When you cut a branch back to the main trunk, a lateral branch or even a bud, the wound heals more quickly than if you leave a stub.

Prune for a reason

Good reasons for pruning include training a young treelike shrub to have one leader rather than a shrubby form, for example. You can also create a special form such as a hedge, topiary, bonsai or espalier through pruning.

However, most pruning is done either to control size or to rejuvenate a plant. Pruning just because the neighbor (or the neighbor’s lawn service) tops his crape myrtles is not a legitimate reason.

If your shrub has any of the four Ds (dead, diseased, damaged or dangerous branches), you may prune at any time of the year — and you should prune right away.

Other reasons for pruning achieve best results by following a pruning calendar. The Virginia Cooperative Extension has prepared an excellent resource for successful pruning. You can find it at bit.ly/guidetopruning.

Timing based on the season

When you prune affects the amount of new growth produced. Plants respond to late-winter and early-spring pruning by producing vigorous growth to replace the removed wood.

When shrubs are pruned during the summer, only a limited amount of new growth is produced in response to pruning.

Late summer pruning often promotes new growth that may not have time to become conditioned for cold weather. This leads to the new growth being susceptible to desiccation. Therefore, it’s probably best to stop pruning before the end of August.

Generally, non-flowering and summer-flowering shrubs (with the exception of hydrangeas) can be pruned when they are dormant (i.e., before May). February is ideal for pruning many of these shrubs. Spring flowering shrubs (e.g., azaleas) should be pruned just after they finish blooming.

Proven techniques

Always prune to something: a bud, a node, a stem, a branch or the ground. Make a cut about ¼ inch from that “something.”

Remember the general rule: prune no more than one-third of a plant at a time. Keep in mind the time of year and the purpose of the pruning.

The cuts should be made at a 45-degree angle. Follow the natural growth habit of the shrub. If you distinguish among the three shrub types — mounding (e.g., abelia, azalea), treelike (e.g., rhododendron, camelia), and cane (e.g., nandina, forsythia) — you will know where to make a cut.

For mounding, take a branch to the ground if possible. For treelike shrubs, go to a stem or the trunk. For canelike habits, take one-third off all canes to a node; alternatively, you may take the oldest canes (one-third of total number of canes) to the ground.

Topping, also called buckhorning or dehorning, is a technique that Master Gardeners discourage. That’s when gardeners cut the entire shrub (or tree) to an arbitrary height. By topping, all of the terminal buds are removed, which stimulates the growth on the outside of the shrub.

You may notice a “witch’s broom” appearance in the structure of the new growth. This prevents water, air circulation and light from entering the inside of the shrub. Disease and insects will find a safe harbor.

Studies have shown that, for crape myrtles, topping reduces the number of blooming days and leads to more suckers growing at the base of the shrub.

Thinning a shrub increases light and air penetration as well as reduces the shrub’s size and improves its structure by removing selected branches. Thinning involves reaching inside a shrub to prune to an inner stem or branch.

Many shrubs benefit from thinning, such as crape myrtles, magnolias, viburnums, spireas, smoketrees, boxwoods and lilacs. More beneficial than topping, thinning cuts also provide some rejuvenation.

Tools of the trade

It’s important to use the proper sanitized tools. Invest in a quality pair of bypass pruners. Sharpen them periodically with a sharpening stone.

Lysol® spray disinfectant is a convenient product to sanitize tools without harming them. Bleach can pit metal. Sanitize your tools between cuts on the same plant when possible, but definitely spray between plants. Do not lay tools on the ground, since this can spread harmful organisms to a cut surface.

When you hold bypass pruners properly, the blades appear to have a smile. Avoid anvil pruners, which crush delicate stems.

You may also need hand loppers and a pruning saw for anything over two inches in diameter.

Hedge clippers work for some applications, but avoid topping. Master gardeners do not suggest using pruning paint or electric shears.

Note: Virginia Cooperative Extension does not endorse specific products and does not intend discrimination against other products that also may be suitable.

Lela Martin is a Master Gardener with the Chesterfield County office of the Virginia Cooperative Extension.