Ed Duke and Sam Hand
Contributors
As a general rule, pruning is best done on small growth, except for the purpose of plant restoration. Mutilating a tree, such as crepe myrtle, by destructive removal of large limbs will produce a lot of new growth.
Crepe myrtles flower on new wood, so yes you will get a lot of flowering but it is flowering which would have naturally occurred anyway on the tree's seasonal spring growth. However, since the tree is deciduous, all you will have to look at next winter after butchering the tree will be a pathetic example of destruction on what could have been a very beautiful and aesthetically well-formed limb structure.
The issue that causes some people to over prune and structurally destroys their crepe myrtles is that some plants do flower and fruit on new growth and others on last year's old growth. Pruning at the wrong time of year may result in fewer flowers and fruits, but it usually will not harm the plant in the long run.
Over pruning, however, especially the unnecessary removal of larger limbs and a majority of the crown, can cause major stress leading to decline and disease, as well as aesthetically and structurally destroying the plant. This information is an attempt to help the homeowner understand when the best time is to prune certain plants.
Perhaps the most confusing group of plants, when it comes to pruning times, includes flowering trees and shrubs. A general rule of thumb is to prune summer and fall flowering trees and shrubs in the dormant season (late winter / early spring).
Prune spring flowering trees and shrubs soon after their flowers fade. The confusion comes with plants like hydrangeas, roses and clematis. Some of these flower in spring, some in summer or fall and some flower repeatedly.
Early spring bloomers set their flower buds the fall before. Pruning them early in the spring would mean losing some blossoms. Following are some helpful tips to assist you in planning your pruning schedule.
Trees and Shrubs to Prune in Late Spring/Summer, (after bloom)
• Azalea (Rhododendron species)
• Bridal wreath spirea (Spirea x vanhouttei)
• Flowering crabapple (Malus species and cultivars)
• Forsythia (forsythia x intermedia)
• Hawthorn (Crataegus species and cultivars)
• Magnolia (Magnolia species and cultivars)
• Mock orange (Philadelphus coronarius)
• Mountain laurel (Kalmia latifolia)
• Serviceberry (Amelanchier x grandiflora)
• Slender deutzia (Deutzia gracilis)
• Weigela (Weigela florida)
Trees and Shrubs to Prune in Early Spring, (while dormant)
• Bradford pear (Pyrus calleryana)
• Butterfly bush (Buddleia davidii)
• Crepe myrtle (Lagerstroemia indica)
• Flowering dogwood (Cornus florida)
• Flowering plum (Prunus blireana)
• Glossy abelia (Abelia x grandiflora)
• Golden rain yree (Koelreuteria paniculata)
• Honeysuckle (Lonicera fragrantissima)
• Hydrangea, peegee (Hydrangea paniculata ‘Grandiflora’)
• Redbud (Cercis canadensis)
• Spirea (except bridal wreath)(Spirea japonica)
• Wisteria (Wisteria species)
Some plants are even more tricky when it comes to when (and what) to prune. For example, big-leaf hydrangeas (Hydrangea macrophylla) bloom on two-year-old wood. Pruning should be done only on growth that produced blooms the previous year.
Following these guidelines will help to assure a more beautiful, healthy and productive landscape. Happy pruning, but do not be prune happy. Panhandle Florida’s foliage plants and flowering trees will appreciate it.
Ed Duke, PhD, is an associate professor in the FAMU College of Agriculture and Food Sciences. Sam Hand is an associate professor and director of Industry Credentialing Training Programs at the FAMU Cooperative Extension.