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About Common Evening-Primrose

Oenothera biennis, the common evening primrose, is a biennial wildflower native to eastern North America. Its bright lemon-yellow flowers open dramatically at dusk, unfurling in just a few minutes — a spectacle that delights gardeners and attracts nocturnal pollinators like hawk moths. Each flower lasts only one night, wilting by the following afternoon, but the plant produces new blooms continuously from midsummer through fall. Growing 90 to 150 cm tall, it forms a basal rosette of lance-shaped leaves in its first year, then sends up flowering stalks in its second year. The entire plant is edible: roots can be cooked like parsnips, young leaves eaten as greens, and the oil extracted from seeds is a globally important herbal supplement rich in gamma-linolenic acid (GLA). Evening primrose oil is widely used in skincare and for managing inflammation. The plant self-sows prolifically and colonizes disturbed ground, roadsides, and railway embankments. It tolerates poor, dry soils and requires little care.

• Edible
• Medicinal

How to care for Common Evening-Primrose

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At a Glance

Bloom time

Fragrance

Toxicity

History

Oenothera biennis is native to eastern and central North America and was introduced to Europe in the early 17th century (reportedly to England around 1619 in a ballast of soil accompanying timber imports). It has since naturalized widely across Europe, Asia, and elsewhere. The species is a biennial — producing a basal rosette of leaves in its first year and a tall flowering stalk (0.9-2 meters) in its second year, followed by death. The flowers are a spectacular evolutionary adaptation to nocturnal pollination: they open dramatically at dusk in a time-lapse-visible few minutes, release an intense sweet lemon-vanilla scent, and attract sphingid hawkmoths that pollinate them through the night.

The plant's seeds are rich in gamma-linolenic acid (GLA, 18:3 ω-6), an unusual essential fatty acid. Evening primrose oil (EPO) was commercialized in the late 20th century as one of the first mass-market herbal supplements — significant research on EPO for atopic eczema, cyclic mastalgia, and premenstrual syndrome has been done; meta-analyses show modest but real benefit for mastalgia and mixed results for eczema. EPO was a top-20 UK herbal supplement throughout the 1990s-2010s.

The young roots, shoots, and flowers are all edible — some Indigenous North American peoples used the roots as a root vegetable. Plant biologist Hugo de Vries's early-20th-century work on O. lamarckiana (a related European cultivated form) was foundational to the development of mutation theory and modern genetics. Native Americans used all parts of the plant medicinally — poultices for bruises, root tea for coughs, and leaf preparations for digestive complaints. European colonists brought it back to the Old World in the 17th century, where it became known as 'king's cure-all.' In the 20th century, scientists discovered that its seeds contain up to 25% GLA (gamma-linolenic acid), launching a multi-million-dollar supplement industry. Today evening primrose oil capsules are among the best-selling herbal supplements worldwide, used for eczema, PMS, and joint inflammation.

Symbolism & meaning

Related plants

More Oenothera plants

• Hartweg's SundropsOenothera hartwegii
• ClockweedOenothera lindheimeri
• Pink Evening PrimroseOenothera speciosa

Plants with similar care

• Chinese AbeliaAbelia chinensis
• Fragrant AbeliaAbelia mosanensis
• Large-Flowered AbeliaAbelia uniflora
• Glossy AbeliaAbelia x grandiflora

Frequently asked questions