Native to eastern and central North America, evening primrose is widely naturalized throughout the world. This tall plant bears beautiful, fragrant yellow flowers that open each day at dusk. The genus name is derived from the Greek term for “wine-scenting,” referring to the ancient use of the roots of related species to flavor wine.
Native Americans ate the seeds of Oenothera biennis as food and made a poultice from the whole plant for treating skin conditions such as bruises. Early American settlers used evening primrose to treat gastrointestinal upset, sore throats, and rashes.
Today the herb is valued mainly for its seed oil, which is used medicinally and as an ingredient in some cosmetics. As many as 5,000 seeds are needed to produce one capsule of evening primrose oil.
Common Names: Evening Primrose
Description: Herbaceous biennial, up to 6 feet tall; crinkled, lance-shaped leaves form a rosette the first year, grow spirally on a stem the second year; fragrant yellow flowers open at dusk
Hardiness: Biennial; to Zone 3
Flowering: Late spring to late summer
Parts Used: Seeds, flowers, and roots
Range/Habitat: Native to North America, widely naturalized
Harvested at the end of the first season, the thick roots have a sweet flavor, similar to that of parsnips. Add the young leaves and shoots to soups and stews; you can also add the flowers to salads. Roast the ripe seeds in the oven and use them in breads, cereals, or other foods.
The oil pressed from ripe evening primrose seeds is a good source of gamma linoleic acid (GLA), an unsaturated fatty acid that reduces inflammation and ensures the health of cell membranes. Some studies have shown that evening primrose oil may help reduce joint pain from rheumatoid arthritis, and it could be useful in the treatment of eczema. People also take the herb for nerve damage associated with diabetes, high blood pressure, high cholesterol, breast pain or tenderness, and other conditions, but additional clinical studies are needed to support these uses.
Grow evening primrose at the back of an informal border, along a fence in a cottage garden, or in a wildflower meadow. Its bright yellow blooms attract sphinx moths and bees; the seeds draw goldfinches.
How to grow it
Evening primrose grows well in poor, dry soil, including coastal sandy areas, in full sun or partial shade. Plant the seeds directly in your garden, scattering them on the surface of the soil, in either spring or fall. Or start seeds indoors in early spring, then transplant seedlings to the garden 6 to 8 weeks later. Harvest the young leaves in early summer. To harvest the seeds, look for the seedpods in midsummer to late summer, after the flowers have faded. Collect the pods when their tops turn brown; inside the pods, the mature seeds should be dark brown and hard. Harvest the roots in fall. Considered an invasive weed in some areas, the plant self-seeds freely.