Agapanthus is a genus of herbaceous perennials that mostly bloom in summer. The leaves are basal, curved, and linear, growing up to 60 cm (24 in) long. They are rather leathery and arranged in two opposite rows. The plant has a mostly underground stem called a rhizome(like a ginger ‘root’) that is used as a storage organ. The roots, which grow out of the rhizome, are white, thick and fleshy.