Feed crepe myrtles a balanced slow-release fertilizer like 8-8-8 or 10-10-10 in early spring as new growth begins.
Most crepe myrtles don’t need heavy feeding, but the right fertilizer at the right time keeps blooms coming all summer. The short answer for what to feed crepe myrtle tree specimens is a balanced granular fertilizer applied in early spring. Skip the special formulas and the urge to pour on extra nitrogen — these trees flower best with a steady, modest nutrient supply rather than a heavy dose.
Best Fertilizer For Crepe Myrtles
A balanced N-P-K formula covers nearly every situation. University extension services consistently recommend 8-8-8, 10-10-10, 12-4-8, or 16-4-8 for established trees. The University of Georgia’s extension service lists those four formulas as working well, while LSU AgCenter suggests 8-8-8, 13-13-13, or a slow-release product applied annually in early spring.
One Tennessee extension guide takes a different angle, recommending a 3-1-1 ratio such as 12-4-4 or 18-6-6. This higher-nitrogen approach suits trees where foliage growth matters, but the balanced formulas remain the safest default for most home landscapes.
Bloom-booster products with high phosphorus (like 10-50-10) occasionally get recommended by commercial sources, but extension experts don’t push them. Skip these unless a soil test shows a phosphorus deficiency.
When To Apply Fertilizer
Feed established crepe myrtles once in early spring, just before or as new growth begins. That single application carries most trees through the season. The Tennessee guide suggests a second lighter application in July for trees that need a boost, but says to stop fertilizing after Labor Day.
Late-season feeding pushes tender new growth that frost will damage. One commercial nursery source recommends stopping about two weeks before the average first frost date (two months before for container plants).
Newly planted trees follow a different schedule. University of Georgia guidance calls for 1 teaspoon of fertilizer per month during the first growing season, sprinkled around the planting hole and watered in.
How Much And How To Apply
For established trees, scatter granular fertilizer evenly over the root zone at the drip line. Keep granules 6–12 inches away from the trunk, lightly work them into the topsoil if needed, and water thoroughly afterward.
| Fertilizer Formula | Rate Per 100 Sq Ft | Best For |
|---|---|---|
| 8-8-8 or 10-10-10 | 1 lb | General feeding, established trees |
| 12-4-8 or 16-4-8 | 0.5 lb | Same coverage, less bulk |
| 13-13-13 | ~0.75 lb | Per LSU guidance, early spring |
| Slow-release 3-1-1 | Follow label | Foliage-heavy young trees |
Always check the package label and follow soil test recommendations where available. Container-grown crepe myrtles need more frequent feeding — a liquid fertilizer every few weeks or a slow-release container formula works well.
What To Avoid With Crepe Myrtle Fertilizer
The most common mistakes come from overdoing it. Too much nitrogen produces lush green leaves at the expense of blooms. Weed-and-feed products can harm these trees because the herbicide portion damages shallow roots. Fertilizing in late fall or winter wastes the nutrients and encourages frost-vulnerable growth.
Organic options work too. Compost, bone meal, and fish emulsion provide gentler nutrition, though extension sources focus mainly on granular balanced products. For a tested list of products that work well, see our roundup of the best crepe myrtle tree food options.
References & Sources
- LSU AgCenter. “Crape Myrtles.” Recommends annual 8-8-8 or 13-13-13 applications in early spring.
- University of Tennessee Extension. “Crape Myrtles: Four Seasons of Beauty.” Covers 3-1-1 ratio feeding and timing guidelines.
- University of Georgia Extension. “Avoid Crape Murder: Prep Your Crape Myrtles for Success.” Lists balanced formulas and monthly feeding for new plants.