Sow into pots in greenhouse or indoors in later winter. Plant out to permanent spots in late spring or early summer - after threat of last frost has passed.
Propagation - division
Divide in spring just before active growth. Plant divisions directly into their permanent spots.
Propagation - cuttings
Take cuttings of mature wood from the current seasonβs growth, 5-10cm long in early autumn. Root out with frost protection.