They will grow easily in temperate climates, though they will need a lot of water to help there growth. Give them fertile soil that drains well but remains moist and a sunny or partial-shaded location. You can propagate from seed or cuttings or by division.
Propagate rock and hybrids by basal cuttings from non-flowering shoots in spring or summer. Species can be increased by seed in autumn or spring. Annuals can be propagated by seed in spring. P.maculata, P.paniculata and their cultivators should be propagated by division in early spring or by root cuttings in winter.
Pests, diseases or disorders
Watch out for red spider mite, eelworm and powdery mildew.