Yes, you can use an outdoor plant box for a small hydrangea, provided it meets the plant’s growing requirements. Hydrangeas thrive in well-draining soil, partial shade, and consistent moisture. When selecting a plant box, ensure it is large enough to accommodate the hydrangea’s root system—typically at least 18 inches in diameter and depth. Opt for a sturdy, weather-resistant material like cedar or fiberglass to withstand outdoor conditions.

To keep your hydrangea healthy, water it regularly, especially during dry spells, and use a balanced fertilizer in spring. Mulching helps retain moisture and regulate soil temperature. Prune dead or weak stems in late winter to encourage new growth. With proper care, your small hydrangea can flourish in an outdoor plant box, adding vibrant color to your garden or patio.

Remember, container-grown hydrangeas may need more frequent watering than those planted in the ground, so monitor soil moisture closely. Happy gardening!