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Common Name: Evening Primrose

General Information

Oenothera biennis is a Biennial up to 1.20 metres tall.
It is harvested from the wild for local use as a food, medicine and source of materials.

Known Hazards

None known

Botanical References

, ,

Range

Eastern N. America - Labrador, south to Florida and Texas. Naturalized in Britain.

Habitat

Dunes, roadsides, railway banks and waste places in Britain[], often in sandy soils[].

Properties

Edibility Rating
Medicinal Rating
Habit	Biennial
Height	1.20 m
Pollinators	Lepidoptera, bees, Self
Self-fertile	Yes
Cultivation Status	Wild

Cultivation Details

Prefers a dryish well-drained sandy loam and a warm sunny position[, , ], though it is tolerant of most soils[]. Heavy clay soils may induce winter rots[]. Grows well on very poor soils[, ]. Established plants are drought resistant[].
Formerly cultivated for its edible roots, the evening primrose is being increasingly cultivated for the oil contained in its seed which contains certain essential fatty acids and is a very valuable addition to the diet[]. See the notes on medicinal uses for more details.
The flowers open in the evening and are strongly scented with a delicious sweet perfume[], attracting pollinating moths[]. The seeds are a good food source for birds[].
Plants usually self-sow freely if they are growing in a suitable position, they can naturalize in the wild garden[, ].

Edible Uses

Root - cooked. Boiled and eaten like salsify[, , , , ]. Fleshy, sweet and succulent[]. Wholesome and nutritious[]. A peppery taste[]. The taste somewhat resembles salsify or parsnips[].
Young shoots - raw or cooked[, , , , ]. Mucilaginous, with a peppery flavour, they are best used sparingly[]. Another source suggests that the shoots should not be eaten[].
Flowers - sweet. Used in salads or as a garnish[].
Young seedpods - cooked. Steamed[].
The seed contains 28% of a drying oil[]. It is edible and a very good source of gamma-linolenic acid[], an essential fatty acid that is not found in many plant sources and has numerous vital functions in the body. The seed contains more than 70% linoleic acid and about 10% gamma linolenic acid[]. The seed, however, is very small and difficult to harvest, it has to be done by hand[]. Overall yields are low, making the oil very expensive to produce. Theoretical yields of 2.5 tonnes per hectare have been suggested, but actual yields are between 0.49 and 1.2 tonnes per hectare[].

Medicinal

The bark and the leaves are astringent and sedative[, ]. They have proved of use in the treatment of gastro-intestinal disorders of a functional origin, whooping cough and asthma[]. A syrup made from the flowers is also an effective treatment for whooping cough[]. The bark is stripped from the flowering stem and dried for later use, the leaves are also harvested and dried at this time[].
Evening primrose oil has become a well-known food supplement since the 1980's. Research suggests that the oil is potentially very valuable in the treatment of multiple sclerosis, pre-menstrual tension, hyperactivity etc[]. It is also taken internally in the treatment of eczema, acne, brittle nails, rheumatoid arthritis and alcohol-related liver damage[]. Regular consumption of the oil helps to reduce blood cholesterol levels and lower the blood pressure[, ]. The seed is a good source of gamma-linolenic acid, an unsaturated fatty acid which assists the production of hormone-like substances[, ]. This process is commonly blocked in the body, causing disorders that affect the uterine muscles, nervous system and metabolism[].
The poulticed root is applied to piles and bruises[].
A tea made from the roots is used in the treatment of obesity and bowel pains[].

Other Uses

The oil from the seed is added to skin preparations and cosmetics. It is often combined with vitamin E to prevent oxidation[].
A yellow dye is obtained from the flowers[].
A finely ground powder made from the flowering stems is used cosmetically in face-masks to counteract reddened skins[].

Propagation

Seed - sow in situ from late spring to early summer[].