The genus Petunia has about 40 species of spreading to erect plants. They are multi-branching, with sticky hairy stems and ovate to lance-shaped dark green leaves. The showy solitary flowers are 5 lobed, fluted, single or double trumpet-shaped and borne on the upper leaf axils of the plant. Petunias are generally thought of as annuals, as they are mostly grown as such, but they are mostly perennials. Many cultivars are derived from P. axillaris, P. integrifolia, and P. violacea – and are split into two groups: Grandiflora petunias (with very large flowers, generally up to 10cm across) and Multiflora petunias (bushier and with many smaller flowers, around 5cm in size).