You should grow them in full sun, make sure you water well and fertilize to prolong the flowering. You can propagate the annuals from seed, the perennials by division in spring and the subshrubs from cuttings towards late summer.
Division in spring, by semi-ripe cuttings in summer or by seed in autumn.
Pests, diseases or disorders
Susceptible to aphids and whitefly under glass; slugs and snails outdoors. Prone to viruses.