It's mid- to late spring and the garden looks lovelier than ever. Your spring-flowering trees are on full display and the last of the spring bulbs are opening up. There's one sticking point, however. Your crepe myrtle (Lagerstroemia spp.) seems to be lagging behind because it has no buds. Have no fear, however. You'll be pleased to know that this much-loved ornamental will soon produce buds, then flower like crazy for much of the summer.
Crepe Myrtle Life Cycle
Crepe myrtle, a member of the loosestrife (Lythraceae) family, grows in U.S. Department of Agriculture plant hardiness zones 6 through 10. After a long winter dormancy, crepe myrtle sends out leaf buds a few weeks or a month later than most ornamental trees. The leaves are followed by peppercorn-like flower buds that appear in late spring. The buds grow and form large panicles, then open up for their grand show in early to mid-summer. Many varieties turn bright colors before dropping their leaves in early to mid-fall.
Like many summer-flowering trees and shrubs, crepe myrtle blooms on new wood. This means the flower buds are formed during leafy spring growth, rather than on the previous summer's growth (old wood). Because of this, crepe myrtle should be pruned while it is dormant in winter or early spring. This promotes an abundance of leafy growth and bud development. If you prune crepe myrtle in late spring, you'll slow down bud development and the tree will bloom later in the season.
A Longer Season
You can usually get crepe myrtles to bloom a second time in a season. After the flowers fade, cut off the spent husks. Called deadheading, this encourages new bud development. Flowers will appear in the weeks to follow. If your summers are very long, you might be able to squeeze a third bloom out of the tree before it needs to go dormant in fall. There is no need to prune or deadhead in fall.
Tips for Success
Crepe myrtle is not picky about soil, but it must have full sun. Six to 8 hours a day is best. Even an hour or two difference in sun exposure can make a big difference in flower production. While crepe myrtle doesn't require rich soil, it does benefit from an annual, light application of fertilizer, just as the leaves start to open in spring. A half cup to 1 cup of 5-10-5 fertilizer sprinkled over the root zone of a medium-sized to large tree is sufficient. Too much fertilizer hampers flowering.