Great mullein is drought-tolerant once established and prefers well-drained soil. Water sparingly, allowing the soil to dry out completely between waterings. Overwatering can lead to root rot.

Focus on deep watering during prolonged dry spells, but avoid waterlogged conditions.

Pruning is typically not necessary for great mullein. Dead flower stalks can be removed after flowering to prevent self-seeding if desired.

In the first year, the plant forms a basal rosette, and pruning this is generally not advised as it prepares for winter.

Great mullein is easily propagated by seed. Sow seeds in early spring or fall directly into the garden or in pots. Seeds require light for germination and should be pressed gently into the soil surface.

It can also spread via self-seeding.

Repotting is not a common practice for Verbascum thapsus, as it is typically grown as an annual or biennial directly in the ground. If starting from seed in containers, transplant seedlings when they are large enough to handle and have developed a few true leaves.