|When and how do I prune a crape myrtle?|
|Crape myrtle flowers on new growth of the season, so you can prune plants any time during the late winter or early spring before growth begins without loss of flower buds. Avoid pruning in early fall before the first frost, because pruning forces new growth and keeps the plant from going dormant. Severe freezes can kill the plant if it is not fully dormant.
Pruning results in an abundance of new shoots that form flowers. It also reduces the amount of vegetative growth and 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.
On some cultivars, pruning to remove spent flower blossoms after they fade will stimulate new growth and another blossom flush in late summer. A second bloom is sometimes difficult to force on cultivars that bloom after mid-July.
The type and amount of pruning that should be done each year depends entirely on desired shape and size. On large old crape myrtles, heavy pruning may not be advisable, since the tree form is the desirable feature. Crape myrtles in tree form make wonderful accent plants or specimen trees. Many cultivars develop attractive trunks with exfoliating bark that add interest to the winter garden.
To develop a tree shape, select three to five nicely spaced shoots growing from ground level as the main trunks. Then remove side branches from these shoots about halfway up their height. As the plant grows taller, more lower branches can be removed each year so the canopy begins 3 to 4 feet above ground level. You may also need to remove suckers (new young succulent spouts that grow from the base) periodically in order to maintain the desired tree shape.
Best wishes with your crape myrtle.