Quick Guide: summer/autumn, half hardy, full sun, height: 45cm-1.2m/18in - 4ft, width: 60cm/24in
Native to South America, these daisy-like flowers bring vivid colour to borders or containers well into the autumn. Varieties are available in shades of yellow and pink.
PROPAGATION Sow seeds in early spring under protection and with gentle heat. Prick out the seedlings into boxes as soon as they are large enough to handle and harden off before planting out 4-5 weeks after sowing.
GROWING Cosmos like a light soil that is not too rich, and do best in warm, dry weather. The delicate stems need the support of stakes. Dead-head the flowers regularly.
VARIETIES C. sulphureus: `Bright Lights' (above) bears small double flowers in yellow, orange and scarlet; `Sunny Gold' is a dwarf strain with small golden flowers. C. bipinnatus: all varieties have fern-like leaves, with flowers of white or deep pink up to 12.5cm/5in across, and reach 7.2m/4ft in height. Choose from 'Candy Stripe', `Gloria' and `Sensation Mixed'.
POSSIBLE PROBLEMS Generally trouble-free.
