The leaves are alternate, ovate to lanceolate, often with a toothed or lobed margin. The flowers are large, conspicuous, trumpet-shaped, with five or more petals, colour from white to pink, red, orange, peach, yellow or purple, and from 4–18 cm broad.
Flower colour in certain species, such as H. mutabilis and H. tiliaceus, changes with age. The fruit is a dry five-lobed capsule, containing several seeds in each lobe, which are released when the capsule dehisces (splits open) at maturity. It is of red and white colours. It is an example of complete flowers