Clethra alexandri prefers consistently moist soil, especially during its establishment phase and throughout the growing season. Water deeply when the top 2-3 cm of soil feels dry to the touch.

Avoid waterlogging, as this can lead to root rot. Reduce watering frequency during winter dormancy.

Prune Clethra alexandri after flowering, typically in late summer or early autumn, to maintain its shape and encourage bushier growth. Remove any dead, damaged, or crossing branches.

Light pruning can be done in late winter to remove any winter damage before new growth starts.

Propagate Clethra alexandri from semi-hardwood cuttings taken in mid-summer. Select healthy shoots, dip the base in rooting hormone, and insert into a well-draining potting mix.

Keep the cuttings moist and in a warm, humid environment until roots form, usually within 6-8 weeks.

Repot Clethra alexandri every 2-3 years, or when it becomes root-bound. The best time to repot is in early spring before new growth begins. Use a slightly larger pot with a good quality, well-draining potting mix.

Ensure the new pot has adequate drainage holes.