Daniel Gill, Merrill, Thomas A.
Pruning often is neglected because gardeners are not exactly sure what to do. There is a great deal of confusion about how to prune, when to do it and even why pruning is done.
Now is an excellent time to evaluate your landscape for pruning that needs to be done, since many plants can be pruned now through February.
The only way to gain confidence in pruning is to do it. Practice makes perfect, as that saying goes.
The first step to gaining confidence is to ask, and fully answer, two questions before pruning begins.
First, ask yourself why, specifically, you feel a plant needs to be pruned. In other words, decide what specific goal you want to accomplish or what problem you need to correct. Some plants won’t grow just the way we want them to, and so they will need to be shaped. There will always be plants that grow larger than we anticipated and need to be regularly pruned to control their size. Dead branches may be pruned for the health of the plant. Sometimes a tree has branches that are too low and cause problems or obstruct views. The list goes on. If you can’t come up with a good reason to prune a plant, however, leave it alone.
Second, decide how you need to prune the plant to accomplish the specific goal you’ve decided on. Before you begin, study the plant carefully and decide what precisely needs to be done. Most gardeners feel they don’t know what they are doing, and they are afraid of damaging or killing the plants they prune. Each plant is different, the desires and needs of each gardener are different and each situation is unique. But if you have identified why you need to prune and what you are trying to accomplish, the task before you will be come clearer.
To accomplish your goals, you should become familiar with the basic pruning techniques we use to shape and control plants.
Heading back involves shortening shoots or branches, and it stimulates growth and branching. Heading back often is used to control the size of plants, encourage fullness, rejuvenate older plants and maintain specific shapes – as in topiary and espalier. Often overused by gardeners, careless heading back can destroy the natural form of a plant in situations where the natural shape is desirable.
Shearing is a specialized type of pruning that is done with a pruning tool called shears, which look like large scissors (There also are gas- and electric-powered shears.). This technique is a variation on heading back that is used to create geometric shapes, espalier or topiary common in formal landscape designs. Shearing should not be used for general pruning purposes, such as controlling size. The result will be clipped formal shapes, which require a lot of work to maintain.
Thinning out removes shoots or branches at their point of origin, either back to a branch fork or back to the main trunk. Thinning cuts can control the size and shape of a plant while doing a better job of maintaining the plant’s natural shape. Thinning also is used for removing branches that are too low on trees. Thinning cuts do not stimulate growth and often work more with the plant’s natural growth patterns to correct problems.
In addition to knowing pruning techniques, you also need to make sure you prune at the proper time. Plants that may be pruned during the winter and early spring include most woody plants, such as trees and shrubs, hedges, screens and foundation plantings that are not grown for their flowers. Both evergreen and deciduous plants may be pruned.
Avoid extensive pruning of spring-flowering trees and shrubs (those that bloom from January through April), such as Japanese magnolia, silverbell, parsley hawthorn, Taiwan flowering cherry, quince, azalea, Indian hawthorn, deutzia, philadelphus, spirea, banana shrub, wisteria and camellia. They have already set their flower buds, and any pruning done before they bloom will reduce the floral display these plants will produce. Summer-flowering trees and shrubs, such as crape myrtle, vitex, althea and abelia, may be pruned now, since they will set flower buds on new growth they produce next spring and summer.
Gardenia, hydrangea, some old garden roses, ramblers and some climbing roses are in a category of their own. They bloom in early summer, but they already have produced their flower buds or flowering shoots for next year. Extensive pruning done from now until they bloom next year will greatly reduce or eliminate flowering next year. Prune these plants in mid-summer soon after they have finished blooming to avoid problems.
Here are some basic recommendations regarding pruning:
–Prune only if necessary and use proper and sharp pruning tools.
–Generally, it is better to prune lightly on a regular basis than to prune severely on an occasional basis.
–Do not prune plants when they are under stress, such as in extremely hot, dry weather.
–Do not prune shrubs and hedges late in the year between September and December, because the new growth it stimulates will not have time to harden off before freezes.
–If needed, extensive pruning should be done to spring-flowering trees and shrubs soon after they finish flowering.
–Prune most summer-flowering trees and shrubs in February.
–Remove dead growth anytime.
Get It Growing is a weekly feature on home lawn and garden topics prepared by experts in the LSU AgCenter. For more information on such topics, contact your parish LSU AgCenter Extension office or visit our Web site at www.lsuagcenter.com. A wide range of publications and a variety of other resources are available.