By LINDA BRANDT, Correspondent
Pruning does for plants what haircuts do for people: It makes them look good. And whether you are pruning to remove damaged tissue, to control size, train a young tree's shape or increase fruit or flower production, it ultimately comes down to aesthetics. While pruning provides satisfaction in knowing you have improved a plant's appearance and health, the "less is more" principle applies. The less you have to prune, the more time and energy you have for other pursuits. All of which emphasizes the importance of choosing the right plant for the place you plan to put it. Annemarie Post, environmental horticultural agent for Sarasota County, points out that a plant that grows to 10 feet in a space that will only accommodate a 4-foot plant will require constant pruning, which can adversely affect the plant's health and longevity, not to mention sustainability in terms of gas and electricity used for equipment and hauling.
That doesn't necessarily mean you can't have your favorite plant. In their "Pruning Landscape Trees and Shrubs" bulletin, University of Florida professors Edward F. Gilman and Robert J. Black note that many landscape trees and shrubs are available as dwarf varieties.
SHAPING
Maintaining the desired size and shape of a plant is the most obvious pruning objective. Selective cutting of outer limbs and branches can shape the silhouette of the plant, while thinning allows sun to reach the interior of the plant, encouraging leaf growth and a fuller plant.
Root pruning can effectively control plant growth and size. Prune half of the root system and wait four to six weeks before pruning the second half. Thoroughly watering the roots after each pruning and keeping the soil around them moist is crucial to the health of the plant.
DISEASED OR DAMAGED
Trimming disease-damaged or insect-infested branches and branch tips can effectively prevent pests and disease from spreading to other parts of the plant or to those nearby. Dip pruners in a 9-to-1 water and bleach solution or spray with alcohol to keep from spreading disease to other plants.
FREEZE DAMAGE
Even in Florida, an occasional cold snap may kill outer parts of limbs and branches. Wait to prune freeze-damaged plants until all danger of frost has passed.
Damaged leaves and branches will provide a protective buffer for the healthy parts of the plant in the event of another freeze. And because pruning encourages new growth, tender young shoots are sure to be damaged by another freeze.
In a way, freeze damage is Mother Nature's way of telling you where to prune. To determine where dead tissue ends and live tissue begins, make a scratch in the bark near the tip of an affected branch. If it is brown underneath, make another scratch closer to the plant. Continue moving down the branch until you see green tissue when you scratch the bark. This is where you will want to cut to ensure new healthy growth. Make the cut about a quarter-inch above a leaf node and in the same direction the node is growing. This is illustrated on page 6 of edis.ifas.ufl.edu/pdffiles/MG/MG08700.pdf.
EARLY TRAINING
Pruning young trees will result in an attractive tree with good branch structure and long-term health. It may also reduce the need for pruning the mature tree. However, if your mature tree does require pruning, call in a professional, preferably a certified arborist. Removing live branches without causing stress and harm to a mature tree requires skill and expertise.
Tree pruning should begin within two or three years after planting. Frequent light pruning several times a year will encourage faster growth and prevent undesirable sprouting.
MORE FRUITS AND FLOWERS
Selectively removing immature fruit can result in larger fruit on certain trees. Light pruning helps maintain annual flowering and fruiting.
Mature citrus trees do not require pruning for fruit production or tree health except when substantial injury occurs following disease or freeze damage.
For information on other Florida fruit trees, consult a nurseryman or your county extension service.
Deadheading, or removing spent blossoms from flowering shrubs and plants, can stimulate new growth and result in more and larger flowers. Pinching new growth on some plants during the growing season can stimulate growth of lateral shoots and increase the number of blooms on plants that bear their flowers at the end of each branch.
BEFORE A HURRICANE
This is not the time to begin pruning out of concern that wind-propelled branches or limbs may damage nearby structures. Better to do regular structural preventive pruning: Trees with properly pruned and maintained crowns offer more wind resistance than unpruned trees.
MORE INFORMATION
In order to properly prune a tree or shrub branch, you need to identify the collar. This is where the branch joins the trunk and can often be identified by a slight difference in the texture and direction of the grain of the bark. Do not cut too close to the collar.
Instead of cutting the branch off flush with the trunk, begin at the top of the joint where the branch abruptly angles out from the trunk. Cut at a slant away from the trunk, leaving the collar intact. For larger branches, two cuts are necessary before this one to minimize damage to the tree.
Make a first cut in the underside of the branch about 12 inches from where it joins the trunk. Make a second cut all the way through the branch from the top either right above the first cut or a little farther out. This removes the bulk of the branch.
This is necessary because if a branch is too heavy to hold itself up once a cut has begun, it can tear down through the collar as it falls.
Once the bulk of the branch has been removed, identify the collar and proceed to cut as directed above.
Excellent illustrations of these techniques can be found at: hort.ifas.ufl.edu/woody/documents/ch_12_mw04.pdf.
MORE USEFUL TERMS AND TECHNIQUES
Heading: Selective cutting of terminal ends of twigs or young branches back to an axillary bud or node. This shortens the shrub and produces vigorous new growth that may actually create a top heavy plant on which lower growth doesn't get enough sunlight. To avoid this, cut the shoots at different lengths.
Thinning: This is the complete removal of branches back to lateral branches, the main trunk, or in the case of shrubs, all the way to the ground. It gives the plant an open appearance and may encourage new growth inside the plant. Cutting branches separately to different lengths will give the shrub an informal natural shape.
Hedging: This is in contrast to hedging, or cutting branches to the same spot. Hedging produces a formal, manicured appearance. Shrubs trimmed in this way should be wider at the bottom than the top to allow light to reach lower foliage.
WHEN?
Once all danger of frost has passed, trees and shrubs can be lightly pruned at any time. Spring-flowering that set buds on the previous season's growth should be pruned or pinched between the end of flowering and late spring. These include azaleas, some hydrangeas, Indian hawthorn, wisteria, star and saucer magnolia.
Plants that set buds on the current season's growth should be pruned or pinched while still dormant or just before the spring growth flush. These include allamanda, abelia, hibiscus, oleander, bougainvillea and vitex.
Most evergreens — holly, jasmines, podocarpus, juniper and wax myrtle — can be pruned any time.
