They first open in the evening and wither the following day. Pollination of this species is done by large hawkmoths and possibly also by hummingbirds. This distinctive feature is very easily seen with a close look at any blossom. The leaves of this plant are narrow and lance-shaped. They are up to 6 inches long.
Most varieties have a silvery sheen due to the many short hairs on the surface of the leaf.
Evening Primrose grows in a low sprawling manner, unlike some of its cousins which may get 5 feet tall. Evening Primrose is a complex of four similar subspecies which occur in the southern half of the Great Plains. Formerly considered a separate species, it has smaller flowers and shorter wings on its seed pods than the other three. Hoary Evening Primrose is densely covered with short hairs. This subspecies is the only one that is completely hairless.