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Gardening in Gwinnett: There is a right way and a wrong way to prune crape myrtles

The crape myrtle is one of the most commonly used flowering trees in landscaping today, as it provides abundant summer color with minimum maintenance. Crape myrtles should be used more often in the home landscape and as street trees in community developments. They are ideally suited for community plantings, as they are long-lived, withstand droughts after becoming established, and are relatively free of disease and insect difficulties.

The horrific practice of chopping off the tops of crape myrtles, often (and aptly) called "crape murder," is overkill. Light pruning is usually all that's necessary.

Crape myrtles are trained by nurseries into forming two basic shapes: single-stemmed tree-form and multi-stemmed. To achieve these shapes, crapes are allowed to grow for a year in either containers or fields, then cut down in the spring of the second year.

Later that summer, when the plant has grown multiple stems from the original root system, the grower will choose the single best stem and train it into a single-stemmed tree-form tree, or choose an odd number of the best stems (three or five, for example) for a multi-stemmed tree. These trees are then grown out to sellable size and purchased by landscapers and homeowners.

Pruning crapes so that they retain the appropriate form is relatively simple. Prune the trees in the winter when dormant, since the flowers bloom on the new growth. It increases the new shoots that form flowers, and reduces the amount of vegetative growth. This funnels the energy of the plant into new growth and flowers.

Pruning, however, is not essential for flowering. Some of the most spectacular floral displays can be seen on old, unpruned crape myrtles along roadsides. Flower clusters are usually smaller on unpruned crape myrtles, but the number of flower clusters is greater. Therefore, the overall floral impact of the plant is not reduced.

For trees that are just the right height or shorter, simply prune off the old flower heads and seedpods. If the tree was perfect last year but the past summer's growth made the plant too tall, remove just that growth. Always remove any suckers that have sprouted from the roots or lower trunk. The key is to not allow the trees to get so overgrown that extreme pruning is ever necessary.

Sometimes though, we may forget to do our yearly maintenance pruning or it may be we take over a property where the previous maintenance person did a lousy job and now a harsh pruning is necessary.

In either case, the trees can be pruned in such a way as to minimize the aesthetic impact of the removal of sizable portions of the tree. Begin by identifying the main stems and remove any others that might have suckered from the roots. Next, prune out any branches that rub and any branches in the interior of the tree that have suckered. Then decide the height you wish the tree to become. Make cuts at the very top of each trunk to remove any growth above that height.

The tree may look a little flat-topped, but you can make shaping cuts to make the canopy the shape you want. I prefer the very top to be a little flat and to taper the sides into a rounded shape. One might describe it as umbrella-shaped.

A good opportunity to obtain some crape myrtles is available now, offered by the Gwinnett County Extension Service. Crape myrtles are for sale at a cost of $5 for 1-gallon sizes. The cultivars include: "Natchez," "Catawba," "Pink Velour," "Sioux" and "Arapaho." Order forms may be obtained at your Extension office located on the fourth floor of the Gwinnett County Government Annex, by calling the Gwinnett County Extension Service at 678-377 4010, or by visiting www.gwinnettextension.org. Click on "events" and you will find the plant sale order form.

Timothy Daly, MS is an agricultural and natural resource agent with the Gwinnett County Extension Service. He can be reached at 678-377-4010 or timothy.daly@gwinnettcounty.com.