The daisy-like composite flower consists of disc florets and ray florets, growing singly at the end of branches or sometimes in inflorescences of terminal corymbose cymes.

The disc florets are pseudo-bisexual and come in several colours such as blue, yellow and purple.

The hardy types usually show a dark blue  in the disc until the yellow pollen is shed.

The ray florets are female and are found diverse colours such as white, cream, pink, purple, mauve to yellow. Some cultivars have "spooned" petals such as "Pink Whirls".

Many species flower a second time late summer, stimulated by the cooler night temperatures. Hardy types show profuse flowering in the spring, but they do not get a second flush of flowers.