Sow indoors in spring. Sow under glass autumn-winter. Indoors, surface sow onto moist, well-drained seed compost. Just cover the seed with a sprinkling of vermiculite. Place in a polythene bag and pop in the fridge at 4°C for 3 weeks then remove to warmth for germination, ideal temp. 15-18°C. A propagator may be used. Keep out of direct sunlight. Germination takes 1-2 months approx. Transplant seedlings into a cell tray and once grown pot on into an 8 cm pot. Liquid feed. Acclimatize and plant out from May. Seed can be sown autumn-winter, surface sow, just cover with vermiculite, place somewhere dry and frost-free, a garage or greenhouse is ideal. In spring when green shoots appear water and keep in a bright frost-free area until all danger of frost has passed.
Prefers fertile well-drained soil in full sun. Shelter from strong winds and stake well. Apply a liquid feed every 2 weeks in the growing season. For best flower spikes thin shoots when 7 cm tall to leave a minimum of 2-3 shoots on young plants and 5-7 on established plants.
Deadhead by cutting spent flower spikes back to small flowering side shoots. This will encourage further blooms. Cut down all growth to ground level once it has withered in autumn.