Four-o'-clock is native to the central section of North America, and it occurs elsewhere as an introduced species, including parts of Europe.

Four-o'-clock is a hairy to hairless perennial herb growing erect to over a meter in maximum height.

The leaves are oppositely arranged mainly on the lower two thirds of the plant below the upper forkings of the stem.

Each five-lobed, funnel-shaped flower is about a centimeter wide and magenta or pink to nearly white in color.

The flowers open for only a few hours and drop, leaving the shaggy-haired developing fruits in the drying, papery cup of bracts.