Northern Prairie Wildlife Research Center
Found throughout North Dakota, gray common evening primrose also occurs from Michigan to British Columbia southward to Arkansas and California at elevations up to 8,500 ft.
Gray common evening primrose is a taprooted biennial up to 4 1/2 ft. tall. Stems can be simple or branched and often sport reddish hairs. Stem bases have a rosette of leaves 4-8 inches long and 1-2 inches wide. Upper stem leaves are shorter and narrower, but all leaves are grayish from a dense cover of pale hairs. Several to many flowers occur on branched or unbranched terminal spikes. The inch-long flowers are yellow when young and fade with age to pale orange. Flowers have a hairy leaflike bract at the base. Fruits are fuzzy cylindrical capsules over an inch long. Capsules hold blackish irregularly-pitted seeds.
Look for gray common evening primrose from July to October on hillsides in native grassland. Unless extremely intense, cattle grazing seems to have little effect on the abundance of this species. Boiled roots of this species are edible, and the young shoots can be used in salads.
This plant belongs to the evening primrose family (Onagraceae) which contains about 600 species including the ornamental fuchsias. Flowers in this family generally open in late afternoon or evening for pollination by night-flying insects. The names Onagra and Oenothera stem from a name used by the Greek intellectual Theophrastos (370-285 B.C.) for the fireweeds that are also members of this family. Oenothera means "wine-scented" in Greek. There are about 150 species in this genus. The specific epithet villosa means "shaggy with long, soft, not interwoven hairs" in botanical Latin. Gray common evening primrose was first described for science by the prolific author Carl Peter Thunberg (1743-1828), professor of botany at Uppsala, Sweden.