New plants should be planted out from spring to early summer, to give the plants enough time to establish themselves and grow bushy before flowering in mid-summer. At the end of summer after flowering and seed collection, the untidy dead stems need to be cut back. During winter the plants go dormant and look almost dead, before new growth shoots in spring. Plants live for 2 - 3 years before dying off. Plants can be propagated from cuttings or seed.
Seed is usually faster, easier and more reliable.
The fine seeds can be sown in autumn or spring. Sow the seeds in a seed tray filled with a well-drained medium and cover lightly with a layer of white sand or finely milled bark. Place the tray in a protected shade area and water regularly. Germination is usually good and within 2 - 3 weeks. The seedlings are sometimes slow to grow, but feed them with an organic fertilizer and plant into individual containers as soon as they are big enough to handle.