It is a quick-growing, much-branched cultivated shrub. It is dicotyledonous and angiosperm, which can grow up to 3m tall.
Its leaves are soft, broad to narrow-ovate and often narrower than Hibiscus rosa-sinensis. Each leaf is about 5-10cm long, with irregularly toothed (serrated) margins.
It blooms most of the year, showy scarlet or pink, and about 5cm long. It is hanging downwards just like a bell, and that is where its common name comes from. The flowers have ten stigmas and numerous anthers protruding out of the protecting petals at the later stage.
Fruits are berry-like, seldom developed in Hong Kong.
