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Crape myrtle control

Q: My very large crape myrtle has gotten out of hand. I’d like to prune it back, but I don’t want to sacrifice its blooms. What’s the best way to prune and shape this shrub, and when is the best time of year to do it?

Elizabeth Graybill, Heathsville, VA

A: Allan Storjohann, mamager of the Myriad Botanical Gardens in Oklahoma City, Oklahoma, replies: Few summer-flowering shrubs that thrive in USDA Hardiness Zones 7 through 9 can match the versatility and show that crape myrtles (Lagerstroemia indica) provide. The shrub’s popularity is growing rapidly, as new introductions of colorful, cold hardy, mildew resistant, and smaller sized cultivars become available in the nursery trade. These woody ornamental plants start blooming in late June here in Oklahoma and continue showing color for two to three months depending on weather conditions. Crape myrtles prefer well-drained soil, are very drought tolerant, and bloom best when located in full sun.

Crape myrtles vary widely in height upon maturity. The largest cultivars may grow to 25 feet, while some of the smallest barely reach 3 feet. Large crape myrtles can be pruned to keep them in bounds, and respond well to the thinning of top growth and the shortening of the branches in its canopy.

As a good rule of thumb to use when you are pruning crape myrtles, don’t be afraid to cut; these shrubs adapt well to a severe pruning once they become unwieldy. Be careful not to overdo it—a practice that is referred to as “crape murder”—as this will delay your bounty of blooms for a season or two. For extremely large specimens, it’s best to gradually reduce its size over a three-year period to keep your bush blooming.

Start by removing all dead and damaged wood and any suckers in late winter or early spring before new growth starts. Then shape and reduce the plant to about 2 feet below the desired bloom height. If the desired bloom height is 8 feet, for example, cut the shrub back to 6 feet. Once the desired height is achieved, an annual shearing may be all that is needed to keep crape myrtle under control. Tree or shrub fertilizer applied after pruning at a rate according to the manufacturer’s instructions will help the plant produce an abundance of new shoots.

From Fine Gardening 61, pp. 15