Evening Primrose, Sun Drop, Common evening primrose

Oenothera biennis

Physical Characteristics

Oenothera biennis is a BIENNIAL growing to 1.2 m (4ft). See above for USDA hardiness. It is hardy to UK zone 4 and is not frost tender. It is in flower from June to September, and the seeds ripen from August to October. The species is hermaphrodite (has both male and female organs) and is pollinated by Lepidoptera (Moths & Butterflies), bees. The plant is self-fertile. It is noted for attracting wildlife. Suitable for: light (sandy) and medium (loamy) soils, prefers well-drained soil and can grow in nutritionally poor soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers dry or moist soil and can tolerate drought.

Distribution

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

Habitats

Meadow; Cultivated Beds;

Edible Uses

Edible Parts: Flowers Leaves Oil Root Seedpod Shoots Edible Uses: Oil Root - cooked. Boiled and eaten like salsify[4, 12, 27, 33, 66]. Fleshy, sweet and succulent[74]. Wholesome and nutritious[2]. A peppery taste[159]. The taste somewhat resembles salsify or parsnips[183]. Young shoots - raw or cooked[2, 12, 52, 85, 183]. Mucilaginous, with a peppery flavour, they are best used sparingly[159]. Another source suggests that the shoots should not be eaten[9]. Flowers - sweet. Used in salads or as a garnish[183]. Young seedpods - cooked. Steamed[183]. The seed contains 28% of a drying oil[114]. It is edible and a very good source of gamma-linolenic acid[141], an essential fatty acid that is not found in many plant sources and has numerous vital functions in the body. The seed, however, is very small and difficult to harvest, it has to be done by hand[160]. Overall yields are low, making the oil very expensive to produce.

Medicinal Uses

Anticholesterolemic Antipruritic Astringent Eczema Hypotensive Miscellany Sedative The bark and the leaves are astringent and sedative[4, 21]. They have proved of use in the treatment of gastro-intestinal disorders of a functional origin, whooping cough and asthma[4]. A syrup made from the flowers is also an effective treatment for whooping cough[7]. The bark is stripped from the flowering stem and dried for later use, the leaves are also harvested and dried at this time[4]. 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[66]. It is also taken internally in the treatment of eczema, acne, brittle nails, rheumatoid arthritis and alcohol-related liver damage[238]. Regular consumption of the oil helps to reduce blood cholesterol levels and lower the blood pressure[21, 66]. The seed is a good source of gamma-linolenic acid, an unsaturated fatty acid which assists the production of hormone-like substances[222, 238]. This process is commonly blocked in the body, causing disorders that affect the uterine muscles, nervous system and metabolism[238]. The poulticed root is applied to piles and bruises[222]. A tea made from the roots is used in the treatment of obesity and bowel pains[222].

Known Hazards

Lowers the threshold for epileptic fits (avoid). Caution if on anticoagulants. Combining with phenothiazines (allopathic medication) can trigger seizures. Adverse effects: may cause headaches and nausea on an empty stomach. Diarrhoea with high doses. Seizures in schizophrenic patients on phenothiazines (allergy antihistamines) [301].