Oenothera biennis

common evening primrose, king's cure-all


Leaf Arrangement


Leaf Attachment

petiolate, sessile

Leaf Margin

dentate, denticulate, repand, serrate

Leaf Type


Leaf Shape

oblong, elliptic, lanceolate

Growth Form


Flower Color


Flower Petals


Flower Month

April - October

Height (meters)

0.5 - 2.0

Milky Sap








Growing Season

Warm season

Wetland Class


Prairie Coefficient of Conservatism


Cultural Information

Mitchell (1926) found seed germination to be best at fluctuating temperatures of 68-77 degrees F (20-25 C). Germination was higher in light than in darkness. Seed germination for all members of the genus oenothera is reported to be improved by cold/moist stratification (Steffen 1997).

Animal Use

The flowers of this plant attract a variety of moths. Small mammals eat the roots and leaves of young plants. Birds eat the seeds. Deer graze older plants. This plant is a special value to native bees.

Natural History

The Acadian French name for evening primrose is "belle de nuit." It is a somewhat weedy species found throughout the eastern United States in open woods, roadsides, and streams. Evening primrose was once grown in Europe for its edible roots, which, when harvested in fall are similar to sweet parsnips. The basal leaves are eaten as greens when harvested in the spring (older leaves may be bitter). The roots harvested under rosettes in the winter and spring, the first year of its biannual life-cycle, can be eaten raw or cooked (Chase 1965). It is possible that other evening primroses are edible as none have been reported poisonous (Harrington 1967). Shirley reports that it attracts ground beetles, a beneficial beetle that eats moths and maggots (Shirley 1994). It ranges from Alberta Canada to Texas and Louisiana.


Dry rocky plains, disturbed areas, lake shores, open woods, fields, roadsides, prairies, waste places, and streams.

Plant Uses

Roots and shoots edible. Clinical trials with Evening Primrose oil indicate that it may be evaluable in treating a number of disorders, including heart disease and arthritis. (Clough) Studies have shown that evening-primrose oil can help treat eczema, asthma, migraine headaches, heart disease, high coholesterol, inflammation, PMS, breast problems, multiple sclerosis, diabetes, rheumatoid arthritis and even alcoholism. (Kershaw) Amerindians used root tea for obesity, bowel pains; poulticed roots for piles, bruises; rubbed root on muscles to give athletes strength (Foster & Duke) Whole plant soaked in warm water used as a poultice to heal bruises.