Q. My crape myrtles have small scraggly blooms that appear in mid-summer. Is there a fertilizer that can help them?
A. Plants that are not performing well in the landscape usually require a full-scale investigation to figure out the problem. Crape myrtles, Lagerstroemia indica, are sturdy, long-blooming Southern favorites. Their Latin name, indica, may give you a clue that their native range is India.
They are a sun-loving, warm-season plant. You may have noticed that their leaves come out later than some of our native plants. They are not spring-blooming plants; they are waiting for that hot summer sun. Their flowers begin to show real color in July, then usually stay in bloom through the month of August. Some cultivars will extend bloom into September.
Mid-summer bloom is not unusual or unhealthy as far as crape myrtles are concerned. Blooms that appear small or unhealthy are probably more influenced by soil, exposure and water levels than they are by fertilizers. Crape myrtles bloom on new wood, which means their foliage has to emerge fully, then the flower buds grow and open. Pruning the plant by thinning out new growth in spring so there are not too many small stems on each branch might result in larger blooms on the remaining branches.
You can apply a balanced fertilizer in spring, and perhaps giving the plants a shot of a super-bloom-type fertilizer in June might also help. But the most important aspect to improvement would be exposure. I think you should check that your crape myrtle is on the warmest side of your garden or house. It should be in full sun and preferably in a spot where the soil warms up early in the season. You may need to relocate your plants for optimum performance. Crape myrtles are best moved while they are still small and in late winter, just before the foliage starts to emerge.
Contact Pat Lea at firstname.lastname@example.org.