Water Ligusticum ajanense moderately, allowing the soil to dry slightly between waterings. Ensure good drainage to prevent waterlogging, which can lead to root rot. Reduce watering in winter when the plant is dormant.

Consistently moist soil during the growing season is ideal for optimal growth.

Prune Ligusticum ajanense after flowering to maintain a tidy shape and prevent excessive self-seeding. Remove any dead, damaged, or crossing stems to improve air circulation and plant health.

Light pruning can encourage bushier growth. Cut back spent flower stalks in late autumn.

Propagate Ligusticum ajanense by division in early spring or autumn. Carefully separate the root ball into smaller sections, ensuring each has healthy roots and shoots. Replant immediately in well-draining soil.

Alternatively, sow seeds in autumn in a cold frame.

Repot Ligusticum ajanense every 2-3 years, or when it becomes root-bound. This is best done in early spring before new growth begins.

Choose a pot that is slightly larger than the current one and use a well-draining potting mix. Ensure the new pot has adequate drainage holes.