Fertilizer for Crape Myrtle: NPK Guide and Application Rates
Crape myrtles are resilient, adaptable trees that bloom prolifically with moderate fertilization. Clemson University Extension recommends a single application of balanced fertilizer in spring when new growth appears. Crape myrtles are not heavy feeders and excessive nitrogen promotes aphid infestations and powdery mildew by producing lush, soft foliage. For established trees in average soil, an annual topdressing of compost may be sufficient.
Quick Reference
What NPK Ratio is Best for Crape Myrtle?
The recommended NPK ratio for crape myrtle is 8-8-8. A balanced 8-8-8 feeds all three macronutrients equally, which works well when soil tests show no single deficiency.
Crape Myrtle NPK needs shift at each growth stage. Balanced formula for newly planted trees during the Seedling phase, then consistent balanced nutrition through summer bloom once flowering begins.
NPK by Growth Stage for Crape Myrtle
| Growth Stage | NPK Ratio | Notes |
|---|---|---|
| Seedling | 10N 10P 10K N 10% Nitrogen: leaf and stem growth P 10% Phosphorus: roots and flowers K 10% Potassium: health and disease resistance Learn more about NPK | Balanced formula for newly planted trees |
| Vegetative | 8N 8P 8K N 8% Nitrogen: leaf and stem growth P 8% Phosphorus: roots and flowers K 8% Potassium: health and disease resistance Learn more about NPK | Moderate balanced feeding for spring growth |
| Flowering | 8N 8P 8K N 8% Nitrogen: leaf and stem growth P 8% Phosphorus: roots and flowers K 8% Potassium: health and disease resistance Learn more about NPK | Consistent balanced nutrition through summer bloom |
| Fruiting | 0N 0P 0K N 0% Nitrogen: leaf and stem growth P 0% Phosphorus: roots and flowers K 0% Potassium: health and disease resistance Learn more about NPK | No fall feeding; allow natural dormancy |
When Should You Fertilize Crape Myrtle?
In zone 6, start fertilizing crape myrtle in April. In zone 10, begin as early as February. Apply every 8 weeks through the growing season.
Which Zones Can Grow Crape Myrtle?
Crape Myrtle grows in USDA zones 6 through 10, spanning a 5-zone range.
Fertilization Start by Zone
| Zone | Start Month |
|---|---|
| Zone 6 | April |
| Zone 7 | April |
| Zone 8 | March |
| Zone 9 | March |
| Zone 10 | February |
What Are the Best Fertilizer Products for Crape Myrtle?
Look for products with an NPK close to 8-8-8. Espoma Tree-tone is the most popular choice among home gardeners for crape myrtle.
- Espoma Tree-tone
- Osmocote Smart-Release
- 8-8-8
Prices vary by retailer and region. Check current pricing before purchasing.
Container and Raised Bed Adjustments for Crape Myrtle
Dwarf varieties in 15+ gallon containers; feed monthly during growing season with liquid fertilizer
Common Fertilizing Mistakes with Crape Myrtle
- Committing 'crape murder' by drastically topping trees, then over-fertilizing to compensate for stress.
- Applying excessive nitrogen, which creates lush growth that attracts aphids and crape myrtle bark scale.
- Fertilizing in fall, which delays dormancy and increases cold damage risk in zone 6-7.
- Planting in too much shade and trying to compensate with fertilizer; crape myrtles need full sun to bloom.
Tips for Fertilizing Crape Myrtle
- Apply balanced fertilizer once in spring when new leaves emerge from bare branches.
- Avoid high-nitrogen fertilizers, which promote aphid populations and powdery mildew.
- Remove spent flower clusters after the first bloom to encourage a second flush of flowers.
- Full sun is more important than fertilizer for crape myrtle bloom; at least 6 hours of direct sun.
Organic Fertilizer Alternatives for Crape Myrtle
Sources
Source:Clemson University ExtensionLast updated: