Stachys thunbergii can be propagated by seeds, stem cuttings, or division.

Seeds should be collected once the flower spikes have dried, usually in late summer or autumn, then cleaned and sown on the surface of a well-drained, seedling mix. They should be kept moist and placed in a warm, bright position, where they typically germinate within three to six weeks. When seedlings are strong enough, they can be pricked out and planted into small pots before being established in garden beds.

Stem cuttings are best taken in spring or early summer, from healthy, non-flowering shoots, avoiding any terminal flowering buds. The lower leaves are removed, and the cuttings are propagated in a medium composed of 70% vermiculite and 30% milled bark. Cuttings should be kept in a warm, humid, shaded environment until roots are formed, usually within three to four weeks, after which they can be potted up and gradually hardened off.

Mature plants can also be propagated by division in early spring or autumn. Clumps should be carefully lifted and separated into smaller sections, each with healthy roots and shoots. Divisions should be replanted immediately into well-drained soil and watered thoroughly to help them establish.

Like many other members of the mint family, Stachys thunbergii prefers full sun to light shade, well-drained, composted soil, and regular watering but take care not to over water once established to avoid root rot. Prune after flowering to keep it tidy and encourage fresh growth.

Because of its softly hairy and aromatic leaves, Stachys thunbergii is generally free from pests, as these traits help deter most herbivorous insects.