Wavyleaf Mullein prefers well-drained soil and is drought-tolerant once established. Water moderately during the first growing season to encourage root development.

After establishment, water sparingly only during extended dry periods. Overwatering can lead to root rot, so allow the soil to dry out between waterings.

Pruning is minimal for Wavyleaf Mullein. Deadheading spent flower stalks can encourage reblooming and prevent self-seeding if unwanted.

Remove any dead or damaged foliage at the base of the plant in late winter or early spring to promote new growth.

Wavyleaf Mullein is easily propagated from seeds sown directly outdoors in autumn or early spring. Seeds can also be started indoors a few weeks before the last frost.

The plant readily self-seeds, so collection of seed pods after flowering is also an option for propagation.

Repotting is generally not required for Wavyleaf Mullein, as it is often grown as an annual or biennial and can self-seed.

If grown in a container and the plant becomes root-bound, repot into a slightly larger container in early spring using a well-draining potting mix. Ensure good drainage to prevent waterlogging.