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Hydrangea Blooming On Plant

With detailed illustrations of how to prune, with specific guidelines for a range of Alabama plants, from azaleas and boxwoods to hydrangeas, junipers, and climbing roses, you can control a plant’s size and shape, encourage flower or fruit production, and discourage disease and promote growth.

Pruning removes growing points called buds.Image of a branch showing laternal bud, node, bud scar, lateral branch, internode, and terminal bud

Pruning removes growing points called buds.

The health and beauty of ornamental plants depend to a great extent on proper pruning. Pruning allows you to control the plant’s size and shape, formal or informal. It also encourages flower or fruit production, and can discourage disease and promote growth by letting light and air into the interior of the plant. Pruning done for any of these reasons is called cultural
pruning. The timing of cultural pruning is important, and depends on the type of plant and the reason for pruning. For most plants, however, fall and early winter are bad pruning times, because the tender regrowth stimulated by pruning can be damaged by cold weather.

Image of pruned branches. Pruning is local in effect in that most of the new growth occurs near the cut.

Pruning is local in effect in that most of the new growth occurs near the cut.

Cultural pruning is done on a seasonal or annual basis. There are times, however, when pruning is urgent, and must be performed immediately, regardless of season. Urgent pruning is done for safety reasons, such as removal of limbs which pose a hazard to people or buildings; and to remove broken, diseased, or dead parts of a plant.

Successful Pruning

The key point to understand about pruning is that the new growth stimulated by pruning develops close to where the cut is made. When you make a pruning cut, you remove the growing point at the tip of a branch, called the terminal bud. Other buds along the branch, called lateral buds, do not develop into growing points because the terminal bud releases hormones which
keep them inactive. Because the pruning cut removes the terminal bud and its controlling hormones, the lateral bud closest to the cut quickly becomes a new terminal bud, and this is where growth will develop.

Thus, if you have a branch that extends beyond the canopy of a shrub, or beyond where you want it, and you make your cut at that point, you’ll very soon have to prune again. Moreover, your shrub will soon become  leggy if pruning is done consistently in this way. If you make your cut inside the canopy of foliage, the new growth will be shaded, and so slower growing, but foliage will develop where it’s needed for a fuller, more attractive shrub.

This basic principle applies to almost all ornamentals. For complete pruning success, of course, you must use the specific pruning techniques appropriate to your particular plants, and you must do your pruning at the right time, and be certain to use the correct pruning tool.

Time to Prune

Flowers or Fruit

Single trunk ornamentals can be pruned to open the center (left) and encourage a spreading form or to keep the plant upright (right).

Single trunk ornamentals can be pruned to open the center (left) and encourage a spreading form or to keep the plant upright (right).

Different plants produce flowers at different times of the year. The buds which produce these flowers also form at different times of the year for different plants. For best flower production, your pruning schedule should be based on accurate knowledge of the particular plant. A gardening encyclopedia or a book on the plant in question is a good source of information.

The general rule of thumb is this: if the plant begins blooming before May, prune immediately after blooms fade; if the plant begins to bloom in May or later, prune in late February or early March, before the start of new spring growth.

Foliage

Plants grown primarily for their green foliage, such as hollies and boxwoods, can be pruned from January through mid-summer.

To preserve the natural form of the plant, prune to a lateral branch one third the diameter of the branch being pruned.

To preserve the natural form of the plant, prune to a lateral branch one third the diameter of the branch being pruned.

Renewal Pruning

Often shrubs become too large or too leggy. Some shrubs can be given a new lease on life through severe renewal pruning. This requires cutting the whole plant down to a stump, and can be done on most broadleaf shrubs, such as hollies, azaleas, and camellias.

Hollies, azaleas, and other nongrafted plants should be pruned to within 4 to 6 inches of the ground. Grafted plants, such as some camellias, should be pruned to within 14 to 16 inches of the ground to avoid stimulating growth from the root stock below the graft.

Junipers and boxwoods should never be pruned to stubs. Narrow-leaf plants, like junipers, do not have buds on their main trunks, which are needed to start new growth. Boxwoods are very slow growers and so respond slowly to severe renewal pruning. Transplant boxwoods to a new location rather than pruning severely.

The time for severe renewal pruning is just before new growth starts in the spring. In southernmost Alabama, Mobile to Dothan, February 15 is a good target date for renewal pruning; in the southcentral region, including Phenix City, Montgomery, and Selma, March 1; in northcentral Alabama, including Birmingham and Anniston, March 5; and in the region north of Gadsden, including Florence, Decatur, and Huntsville, March 10.

 

Informal – Single Trunk

To maintain a natural, informal effect on single trunk ornamental shrubs, first select the branch to be pruned and cut back to a lateral branch or a bud. When pruning back to a lateral, a good rule of thumb is to prune to a lateral branch which is one-third the diameter of the branch being removed. Following this guideline will help maintain the natural form of the plant.
Another consideration is the direction of the new growth. This can be selected by choosing the bud or branch. Simply prune to a bud or branch pointing in the direction in which new growth is desired. Leave less than ½-inch of stub to keep injury to a minimum.

When a multiple trunk, cane-type shrub needs pruning, remove one-third of the canes to the ground and cut one-third halfway to the ground to encourage new growth throughout the plant. Pruning only the tops will result in new growth only at the top.

When a multiple trunk, cane-type shrub needs pruning (left), remove one-third of the canes to the ground and cut one-third halfway to the ground to encourage new growth throughout the plant (upper figures). Pruning only the tops will result in new growth only at the top (lower figures).

Remove V-crotches (narrow-angled) and crossing branches which create weakness in a tree.

Remove V-crotches (narrow-angled) and crossing branches which create weakness in a tree.

Informal – Multiple Trunk – Large Shrubs

Large shrubs and small trees with multiple trunks, such as crapemyrtle, need some annual pruning using the guidelines for single trunk plants. Diseased, weak, broken, or unwanted trunks should be removed as needed.

Informal – Multiple Trunk – Small Shrubs

Multiple trunk small shrubs are also known as cane-type shrubs. Examples of these include nandina, spiraea, and abelia. Older branches of these plants should be cut to the ground annually. For vertical shrubs, like nandina, start a sequence: prune one-third of the canes to the ground, prune another third half-way to the ground, and leave the remaining canes uncut. After this initial pruning, annually remove the tallest canes to the ground. This will result in foliage and berries from the ground to the top of the shrubs versus foliage only at the top.

To maintain a formal hedge, the sides must be sloped slightly to make the top narrower than the bottom. Pruning the side vertically will shade the lower leaves and result in leggy growth.

To maintain a formal hedge, the sides must be sloped slightly to make the top narrower than the bottom (left). Pruning the side vertically will shade the lower leaves and result in leggy growth (right).

Formal Hedges

Trimmed, formal-type hedges should be pruned so that it is wider at the bottom than at the top. Hedges pruned this way should maintain this shape. If the sides of the hedges are pruned vertically, the lower branches may be lost due to shading by higher branches. This exposes the trunks of the hedge and usually will not be very attractive

Trees

A young tree needs pruning to build a strong framework and, quite often, to correct developing faults. Prevent formation of v-crotches and crossing of limbs.

Prune young trees frequently. This usually eliminates the need to remove large branches which may disfigure trees for a number of years, and it saves the cost of hiring professional tree workers.

Generally, trees should not be topped. Topping can ruin the beauty of a tree for many years and defeat the purpose of pruning. Pruning is stimulatory and promotes thicker, more rapid growth of suckers and water sprouts. Soft, new, rapidly growing branches in treetops are easily damaged by wind. Also, cut surfaces are susceptible to insects and disease.

Any wound must close over if the plant is to stay healthy. Wound dressings contribute little or nothing to the healing process. Nor do they protect against rot. Cosmetically, they may have some value. In general, the tree is able to close over the wound itself. This is why it is important to make the final pruning cut close to the main trunk. It will gradually heal itself.

Prune old, established trees during winter or early spring. Dead limbs are more easily seen when trees are in foliage. However, early winter pruning is better for some tree species; maples and elms tend to bleed if cut in active growth. Pines pruned in spring and summer are more susceptible to insect problems; they must be pruned in winter.

To prune large tree limbs, follow the illustrated sequence, making the final cut close to the trunk. Smooth the edges of the final cut with a rasp or knife to encourage healing.

To prune large tree limbs, follow the illustrated sequence, making the final cut close to the trunk. Smooth the edges of the final cut with a rasp or knife to encourage healing.

Removing Large Tree Limbs

First, cut through about one-fourth of the diameter of the limb on the underside, 1 to 2 feet from the trunk of the tree. Make the second cut further out than the first—a distance equal to three times the diameter of the limb. Cut from the top until the limb is severed. Then cut the stub at the swollen base (branch collar) of the main trunk or as close as possible to another major limb. Leave only a narrow ledge at the top. Make the cut as smooth as possible.

Special Plants

Crapemyrtle

Since crapemyrtle flowers in summer, it should be pruned before new growth begins in the spring. Crapemyrtle will tolerate heavy pruning. In fact, to have a multiple-trunk crapemyrtle, you should cut it to the ground. Many trunks will sprout. Repeat the next year if more trunks are desired. If a single trunk is desired, prune as needed to keep to a single trunk.

To reduce work, select a tree form variety to plant if a tree is desired and use a smaller growing shrub form for a shrub effect.

Camellia

Camellias do not need pruning every year. Prune camellias to maintain an attractive form. This usually involves removing any long stringy growth. Camellia enthusiasts like to prune to a more open canopy form.

The common camellia (Camellia japonica) is normally grafted on to the roots of sasanqua camellia. Occasionally, this sasanqua root stock will sprout a sucker which produces flowers which differ in color and form from the rest of the plant. These suckers should be removed completely or they may soon dominate the plant.

Some camellias bloom in the fall, some in winter, and some in spring. If pruning is needed, prune fall and winter bloomers in March. Prune spring bloomers after flowers have faded.

When pruning shrubs that have been grafted, always remove new twigs that start below the graft.

When pruning shrubs that have been grafted, always remove new twigs that start below the graft.

Hydrangea

Hydrangeas are an exception to the normal May rule of thumb. They are summer bloomers, but should be pruned immediately after flowering. Cut flowering canes back to within 2 feet of the ground. If a hydrangea fails to bloom, cut all canes back to within 2 feet of the ground in July.

Roses

Of the many garden plants, roses respond most readily to pruning, resulting in larger blooms, more substance and better color. Many more blooms may be produced by pruning.

Because of variations in flowering and growth habits, not all rose varieties are pruned alike. A general rule to follow is to prune weak-growing varieties lightly and vigorous-growing varieties more severely. In selecting canes to be removed, examine them carefully for wounds, split bark, or signs of disease or crowding,
and remove these first.

Hybrid Teas

Prune hybrid tea rose types in early spring just before or immediately after the beginning of new growth. Immediately after the last frost date, remove canes or stems showing winter damage, disease or insect damage. Prune the remaining canes to 15 to 18 inches above the ground. Longer canes may be left if desired. Leave a minimum of three to five of the healthiest, most vigorous canes on each plant.

All cuts should be made ¼ inch from a bud, whether on a healthy or diseased cane. Use sharp, clean pruning shears to make cuts.

Prune hybrid teas in late March or after danger of cold weather passes.

Prune hybrid teas in late March or after danger of cold weather passes.

Floribundas and Grandifloras

These roses should not be pruned as heavily as hybrid teas. Often these roses grow to a considerable height and produce more blooms. Cut back an inch below any darkened area to remove any dead and diseased wood. The entire branch should be removed if it is badly diseased or dead. Three to five strong, healthy canes should be left. Next, any canes having weak growth or those growing toward the center of the plant should be removed. Any remaining canes should be cut 18 to 24 inches above the ground, depending upon the plant’s vigor.

Prune climbing roses after first flush of flowering in spring. Keep plant within limits of trellis or support.

Prune climbing roses after first flush of flowering in spring. Keep plant within limits of trellis or support.

Climbing Roses

Climbers have variable blooming habits. Many varieties produce blossoms in spring only. During this flowering period, new canes develop for next season’s flowers. Cut several old canes to ground level immediately after flowering.

Some climbers bloom off-and-on throughout the growing season. Many produce new canes on old canes, rather than from the base of the plant. In early spring, remove some older canes, leaving only five or six of the healthiest, most vigorous ones. This will keep the plant from becoming too thick or scraggly and will help produce more attractive blooms and plants.

Most climber canes produce good blooms for only 2 years. If heavy branching occurs on the remaining five or six canes, remove some side branches. Remove old, faded flower clusters on varieties which bloom periodically throughout the growing season.

Tools for pruning include a pruning knife, lopping shears, pruning saw, hedge shears, a wood rasp, and hand pruners.

Tools for Pruning

To do a good job of pruning, you need good quality, sharp tools which are designed for the type of pruning to be done. The most commonly used piece of equipment is hand pruners. These shears can be used on branches three fourths of an inch in diameter or smaller. There are two types, anvil and scissors. The anvil type is lighter and less expensive, but crushes a small portion of stem. Used properly, the scissors type cuts closer, without crushing the stem and usually lasts longer.

Lopping shears are used on branches up to about one and a half inches in diameter. They vary in handle length from about 20 to 36 inches. They are also available in scissors or anvil types, but in this case most anvil types are more expensive, with gear assisted jaws for heavy duty work.

Branches over one and a half inches in diameter require a saw. Pruning saws have coarse teeth and a curved blade designed for fast cutting on the pull stroke. For very large limbs, a large saw or chain saw is the best choice. A pruning knife or wood rasp is useful to smooth edges of large cuts to promote rapid healing.

Hedge shears are designed for clipping foliage to create a formal appearance. They are often misused. Unless you want a strictly formal hedge, you won’t need this tool. Boxwoods, Japanese hollies, dwarf yaupon, and other plants with many limbs and small leaves, however, may require too much time to prune using other tools. If you use hedge shears on these plants, use them with care.

Keep tools sharp, lubricated, and clean. Some shears and loppers are made with removable blades, making sharpening and replacing blades easier. Clean and coat tools with light oil after use to prevent rust. When pruning diseased branches, dip the shears in a disinfectant (10 percent chlorine bleach solution or rubbing alcohol) after each cut. If you don’t use a disinfectant dip, you might spread the disease to healthy plants. Dip is caustic to shears, so clean and oil them after using a dip.

Download a PDF of Pruning Ornamental Plants, ANR-0258.

 

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