A history of the evening primrose and its uses

Evening primrose plants belong to the genus Oenothera, which includes 157 accepted species, all native to the Americas. The best known, and most widely used, is the species O. biennis, which has naturalised across much of the world, including in the British Isles and mainland Europe.  

It is found growing on a multitude of different sites—dry waste ground, roadside verges, along railway cuttings and in sand dunes. Like many plants with properties useful to people, evening primrose has a history associated with colonialism and commodification: during the 1600s European colonialists exported goods from North America, including plants and plant products, for sale in Europe. It is likely that common evening primrose was first introduced into Europe as an ornamental plant in the 17th century, and was grown in botanic gardens for its attractive, showy flowers. Knowledge held by Native American peoples of the plant’s diverse medicinal uses was also appropriated by the Europeans, giving rise to another name for the plant, "King’s cure-all".  

O. biennis is an erect biennial, growing up to six and a half feet in height, with a deep, fleshy, fibrous taproot that anchors it in the ground. In the first year after germination, evening primrose plants develop into a leaf rosette, with long and narrow lance-shaped leaves which often have a reddish hue. The large, scented yellow flowers bloom on tall spikes from June to September in the second year. The cup-shaped flowers typically open at dusk (hence the well-known name "evening primrose")—attracting pollinators with nocturnal feeding habits, primarily moths such as the hawkmoth. Flowers remain open until morning, or later, if the day is cloudy. Seeds that form after pollination are released close to the parent plant, remaining viable in the soil for decades but may be dispersed by wind and birds.  

Evening primrose was an important food source for several Native American tribes, including the Cherokee, who cooked the leaves to eat them as greens, and ate the boiled roots like potato. Roots of Oenothera species were also a staple food for the Navajo, Cheyenne and Pawnee and were either roasted or boiled, providing a valuable source of nutrition. This is especially true for the Pawnee, who collected and stored the roots for use as a food source during the winter months. Evening primrose seeds were used by the Zuni people, who roasted and ground them into a nutritious meal (coarse flour) with which to make bread and other dishes. The Apache used the ground seeds of the prairie evening primrose, O. albicaulis, to make a gravy, and boiled the seeds in soup.  

Native American tribes also used evening primrose plants in traditional medicine to treat a variety of ailments, and they played a significant role in religious and spiritual ceremonies. For some Native American peoples, evening primrose is sacred, with the yellow flowers perceived as symbolizing the sun and embodying its power and life-giving properties.  

In modern herbal medicine, evening primrose oil (which is extracted from the seeds of O. biennis) is taken internally as a dietary supplement to provide essential fatty acids, notably gamma-linolenic acid (GLA), which is believed to support regulation of hormone levels, helping to alleviate premenstrual syndrome, breast pain and menopausal symptoms. It is also used to treat symptoms of rheumatoid arthritis, diabetic neuropathy and attention deficit hyperactivity disorder (ADHD). Topically, the oil is used to treat dry skin and eczema. Numerous clinical studies have had conflicting results, with strong evidence lacking for the efficacy of evening primrose oil in treating these conditions.  

The oil is used in many skincare and cosmetic products as a moisturiser, emollient and anti-inflammatory. Defatted seeds (leftover from oil production) show high antioxidant activity and are rich in fibre, and it has been suggested these could be used as a functional food ingredient for diabetes.

The common evening primrose plant has several environmental uses, including soil conservation, as the deep roots help to prevent soil erosion and retain soil moisture. Evening primrose is commonly used to prevent erosion along coastal areas by stabilising sand dunes. The plant has also shown promise in phytoremediation (the use of plants in reducing or removing contaminants), as it is effective in removing pollutants such as heavy metals from contaminated soils. It is also beneficial to wildlife, as the flowers are rich in nectar for pollinators, and the seeds and leaves provide a food source for birds and other animals. As a fast-growing plant, evening primrose can also help to sequester carbon dioxide from the atmosphere and store it in the soil.