Do Crepe Myrtles Need Full Sun?

Defining Full Sun

• More than one gardener has made the mistake of trying to grow crape myrtles in too much or too little sun. Understanding what full sun means -- and whether your planting site has it -- prevents a serious mistake. The University of Illinois Extension recommends that plants needing full sun should get at least six hours of direct sunlight each day. Whether they're continuous or interrupted doesn't matter, as long as the total number of hours is six or more.

Excessive Sun Problems

• Crape myrtles planted in hot, dry climates do best with morning and late afternoon sun. From midday to mid-afternoon, they benefit from shade. If you live in such a climate, avoid sites with southern or western exposure; they receive the strongest, hottest afternoon light. Crape myrtles planted in these areas also suffer from the reflected light and heat of nearby light-colored structures or pavements. Sun-stressed plants frequently have dry, brown-edged, prematurely dropping leaves.

Inadequate Sun Problems

• Crape myrtles receiving less than six hours of direct daily sun can't photosynthesize the food necessary for vigorous growth and flowering. Inadequate sunlight also exposes them to fungal infections. The University of Georgia College of Agriculture and Environmental Sciences cautions that sun-deprived crape myrtles have an increased risk of developing powdery mildew, a shade-loving, leaf-blemishing fungus. If your crape myrtle is hosting aphids, scales or other honeydew-producing insects, it is more likely to attract black sooty-mold fungus than plants in full sun.

Growing the Healthiest Crape Myrtles

• As important as the right amount of sun is, crape myrtles won't do their best unless you meet their other cultural requirements. They need consistently moist, well-drained soil, are happiest in loamy clay and benefit from slow, deep watering during prolonged dry weather. For maximum flowering, feed them with a slow-release, high-nitrogen 16-4-8 fertilizer. In the first year after planting, apply 1 teaspoon of the fertilizer each month from March to August around the edges of the planting holes. After they’re established, scatter the fertilizer over the root zones in early spring at the rate of 1/2 pound per 100 square feet of soil and water it in. Don't overfeed because excessive nitrogen stimulates foliage at the expense of blooms.