Daniel Gill, Merrill, Thomas A.
By Dan Gill
LSU AgCenter Horticulturist
Pruning is a gardening job that is often 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.
Pruning is something that you just have to get used to doing.
Some plants won’t grow just the way we want them to, so they will need to be shaped. Of course, there always will be plants that grow larger than we anticipated and need to be regularly pruned to control their size. In addition, dead branches, diseased tissue and insect infestations may be pruned for the health of the plant.
That list could go on. But let’s just say pruning simply is a part of regular gardening activities.
Plants that may be pruned during the winter and early spring include many trees, shrubs, fruit trees and hedges. Both evergreen and deciduous plants may be pruned.
Avoid extensive pruning of spring-flowering ornamental 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 already have set their flower buds, and any pruning done before they bloom will reduce the floral display these plants will produce.
Crape myrtle, vitex, althea, oleander, American beautyberry, buddleia, abelia and other summer-flowering trees and shrubs may be pruned now. They will set flower buds on new growth they produce this spring and early summer.
Shrubs that are not grown for their flowers, such as ligustrum, privet, viburnums, cleyera, dwarf yaupon, junipers and others, also may be pruned now.
There are a few exceptions among the summer-flowering shrubs, however. Early summer-flowering shrubs, including gardenia, hydrangea, some old garden roses and many climbing roses, bloom on the growth they made last year. Extensive pruning done from now until they bloom will greatly reduce or eliminate flowering. Prune these plants in mid-summer soon after they have finished blooming.
Once you have decided to prune, the real dilemma is exactly how to do it – particularly since most gardeners feel they don’t know what they are doing.
And, admittedly, fruit and nut trees generally are best pruned in a particular way, so you should seek appropriate specific recommendations when dealing with these types of plants.
In most instances, however, there are not exact recommendations for how you should prune plants in your landscape. Each plant is different, the desires and needs of each gardener are different and each situation is unique.
But some of the things you definitely want to do are at least to make sure you prune at the proper time and follow some basic pruning techniques.
"Heading back" involves shortening shoots or branches and 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.
"Shearing" is a specialized type of pruning that is done with pruning tools called shears or hedge trimmers. This technique is a variation on heading back and is used to create geometric shapes, clipped hedges, espalier or topiary commonly in formal landscape designs. Shearing tools should not be used for general pruning purposes, such as to control size.
"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 cuts do not stimulate growth and often work more with the plant’s natural growth patterns to correct problems.
The only way to gain confidence in pruning is to do it.
The first step to gaining confidence is to ask, and fully answer, two questions before pruning begins. First, ask why, specifically, you feel this plant needs to be pruned – what problem do you need to correct? If you can’t come up with a valid reason to prune a plant, leave it alone. Second, ask how you need to prune the plant to accomplish the goal. Study the plant carefully and decide what specifically needs to be done before you begin.
Finally, here are some basic recommendations regarding pruning.
It is unlikely that you will kill or permanently damage a plant under most circumstances, even if you do something wrong when you prune. So grit your teeth and go for it. The more you prune, the better and more confident you will become.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.