If you're considering growing a small clethra (Clethra alnifolia) in an outdoor plant box, the answer is yes—with a few considerations. Clethra, also known as summersweet, is a versatile shrub that thrives in moist, well-drained soil and partial to full sun. When planting in a container, ensure the box is large enough to accommodate the plant's root system, ideally at least 18-24 inches deep and wide.

Choose a high-quality potting mix with good drainage to prevent waterlogging, as clethra prefers consistent moisture but not soggy conditions. Regular watering and occasional fertilizing will help maintain healthy growth. Additionally, since clethra is hardy in USDA zones 3-9, ensure the plant box is durable enough to withstand seasonal changes if left outdoors year-round.

Container-grown clethra can be a beautiful addition to patios, balconies, or small gardens, offering fragrant summer blooms and attractive foliage. Just monitor its growth and repot if it becomes root-bound. With proper care, your small clethra will thrive in an outdoor plant box!