Water common comfrey regularly, especially during dry periods. Keep the soil consistently moist but not waterlogged. Reduce watering in winter.

Adequate moisture promotes vigorous growth and prevents the plant from becoming leggy or stressed, ensuring good biomass production for harvesting.

Prune common comfrey back hard after flowering to encourage a second flush of growth and prevent self-seeding. Remove dead or damaged foliage at any time.

Cutting the plant down to the ground in late autumn or early spring also revitalizes it for the coming season.

Common comfrey is easily propagated by division of its rootstock in early spring or autumn. It can also be grown from seed, though divisions are often preferred for true-to-type plants.

Simply cut a piece of root and plant it about 5 cm deep in moist soil.

Repotting is generally not necessary for established outdoor plants as comfrey is a vigorous perennial. If grown in a container, repot every 2-3 years in spring into a larger pot using a rich, well-draining potting mix to accommodate its extensive root system.