Moth mullein prefers well-draining soil and is drought-tolerant once established. Water moderately during the initial growth period and during prolonged dry spells. Avoid overwatering, as this can lead to root rot.

Allow the soil to dry out slightly between waterings for optimal health.

Deadheading spent flower stalks can encourage a longer blooming period and prevent self-seeding if unwanted.

Remove any yellowing or dead foliage in late fall or early spring to maintain a tidy appearance and promote new growth. Minimal pruning is typically required.

Moth mullein is easily propagated from seeds, which often self-sow readily. Sow seeds directly outdoors in early spring or fall.

Division of established clumps in spring or fall is also possible, though less common due to its biennial or short-lived perennial nature. Seeds germinate easily.

Repotting is generally not a common practice for moth mullein, as it is often grown as a biennial or short-lived perennial and can be easily propagated from seed. If grown in a container and it becomes root-bound, repot in spring to a slightly larger pot with well-draining soil.