Hibiscus: annual hibiscus
Height 38-75cm (15-30in)
Planting distance 23cm (9in)
Flowers late summer to early autumn
Rich, moist well-drained
Sunny sheltered site
Hardy and half-hardy annuals
There are few more exotic looking plants than thehybrids with their wide, funnel-shaped, richly coloured . They are showy but rather short-lived though more blooms follow in quick succession. The plants are suitable as dot plants in mixed borders, for bedding schemes and for growing in tubs on the patio.
Popular species and varieties
moscheutos is a moderately hardy perennial usually treated as a half-hardy annual. The species is rarely grown, having been superseded by F1 hybrids such as ‘Disco Belle’ (syn. ‘Les Belles’). These grow up to 50cm (20in) tall and bear huge, near-circular flowers, 20cm (8in) or more across; they are pure white, sometimes with a rosy centre, or pink or deep cerise red. Also available in the pure white form ‘Disco Belle White’. Hibiscus trionum (flower-of-an-hour) is a hardy bushy annual, up to 75cm (2-1/2ft) tall, with dark green, coarsely toothed leaves. The five-petalled, creamy-white flowers with chocolate-maroon centres are much smaller, about 5cm (2in) wide, and very short-lived, but they are produced continuously during late summer and early autumn. The variety ‘Sunnyday’ (height 38cm/15in) has cool lemon-yellow blooms with purple-black centres.
Sow seeds of Hibiscus trionum in the flowering site inand thin the seedlings to 23cm (9in) apart. The species often self-seeds if the soil is left undisturbed.
Sow seeds of the half-hardy hybrids under glass in late winter at a temperature of 16-18°C (61-64°F). When the seedlings are large enough to handle, prick them off singly into 7.5cm (3in) pots of compost and grow on at the same temperature. Harden off in a cold frame before planting out in a sheltered site when all danger of frost has passed.
All annual hibiscus perform best in rich, moist but well-drained soil and in a sunny site.
Pests and diseases