Quick Guide: summer, hardy, full sun, height: 45-60cm/18-24in, width: 45-60cm/18-24in
Native to North America, the coreopsis is an accommodating plant, producing cheerful yellow star-shaped flowers throughout the summer even in polluted atmospheres.
GROWING Set out young plants between autumn and spring in well-drained, fertile soil. Chalky soils are tolerated. A position in full sun in an open border is preferred. Cut back some stems in late summer to encourage perennial growth.
PROPAGATION Divide established plants in early autumn or very early spring, making sure that each portion has 4-5 new shoots. Replant immediately. C. grandiflora can be increased by 7.5cm/3in basal cuttings taken in summer and rooted in a cold frame.
SPECIES C. verticillata (above), very fine leaves, a succession of star-shaped flowers 2.5cm/1in wide from mid to late summer; C. grandiflora, a short-lived perennial, up to 90cm/3ft high, bearing large daisy-like flowers all summer. This is the best species for cutting; named varieties include `Mayfield Giant', Sunray', double flowers, and `Goldfink', dwarf at 23cm/9in.
POSSIBLE PROBLEMS Froghoppers damage young shoots.
