Question: are 4 o'clocks perennials or annuals?
Answer: The common name of four o'clocks was given to Mirabilis jalapa because the flowers of this plant do not open until late in the day. This old-fashioned garden ornamental in the four-o'clock family (Nyctaginaceae) is a tender perennial hardy in Zones 7-10, generally grown as an annual throughout most of the US.