Twelve inch spikes of countless purple-blue flowers open on strong branching stems in spring and summer, although very few good seeds are often produced. This really is a perennial in a sheltered situation, e.g. in a large pot or a very protected garden. In The Scilly Islands and the South West of the UK this plant often makes a long-lived small tree.
Seeds are best sown in spring or before mid summer to enable a full season of growth and are best sown where actually needed, preferably in a well-drained and sheltered spot. Otherwise, sow seeds, covering very thinly, in early spring onto a good soil-based compost in a frost-free place. No artificial heat is needed to help germinate these seeds, just a cool, varying, background temperature, in good light. Seedlings usually appear in 3 to 4 weeks. Pot on into a gritty compost containing very little organic material before planting out as small plants in a well-drained sheltered spot, or a large container that may be taken in during the winter in severe frost. Plants usually flower 24 months after sowing and can occasionally vary in habit and flower colour as we have numerous species growing here, and very many busy bees.