Growing a small crepe myrtle in an outdoor plant box is entirely possible with the right care and conditions. Crepe myrtles, especially dwarf or compact varieties, thrive in containers when given adequate space, sunlight, and proper drainage.

Choosing the Right Variety: Opt for dwarf or miniature crepe myrtle cultivars like 'Pocomoke' or 'Razzle Dazzle,' which are bred to stay small and adapt well to container life.

Plant Box Requirements: Ensure your plant box is large enough (at least 18-24 inches deep and wide) and has drainage holes. Use high-quality potting mix enriched with organic matter to promote healthy root growth.

Sunlight and Watering: Crepe myrtles need full sun (6+ hours daily). Water regularly, keeping the soil moist but not soggy, and reduce watering in winter.

Pruning and Fertilizing: Light pruning in late winter encourages blooms. Feed with a balanced, slow-release fertilizer in spring.

With these steps, your crepe myrtle can flourish in a plant box, adding vibrant color to patios, balconies, or small gardens.