Growing a small buttonbush (Cephalanthus occidentalis) in an outdoor plant box is entirely possible, provided you meet its basic needs. Buttonbushes thrive in moist, well-drained soil and prefer full sun to partial shade. When selecting a plant box, ensure it is large enough to accommodate the shrub's root system—ideally at least 18-24 inches deep and wide.

Drainage is critical; choose a box with holes or add a layer of gravel to prevent waterlogging. Regular watering is essential, especially during dry spells, as buttonbushes love consistently damp soil. Fertilize lightly in spring to encourage healthy growth.

While buttonbushes can adapt to container life, they may eventually outgrow the box. Pruning helps manage size, but consider transplanting to the ground if the shrub becomes too large. With proper care, an outdoor plant box can be a great temporary home for a small buttonbush, adding unique beauty to patios or balconies.