COMMON EVENING PRIMROSE, OENOTHERA BIENNIS
There are around 125 species of Oenothera, or the evening primrose, but the common one which we get evening primrose oil from is this yellow one which originated millennia ago in Central America and spread throughout the North American continent. It was taken to Britain Germany
The name of the genus, Oenothera comes from the Greek with oeno meaning a honeyed wine (like nectar) and thera meaning hunter or seeker, so the evening primrose is the plant for nectar seekers. The flowers on the top of the stem bloom first, and so have seed pods first, but the whole plant continues to flower in layers and continues growing until autumn. It flowers in the evening (as its name suggests) and is pollinated by butterflies and moths as well as other insects which fly during the evening.
The whole plant is edible, and the flowers can be used in salads or as garnishes and a yellow dye can also be produced from them. The young shoots can be used in salads and these have a peppery flavour and should be used sparingly. It is the seeds from which the oil is extracted and these can be eaten in the young seed pods or roasted when extracted from the pods. Just roast them in the oven at 350° F for 15 – 20 minutes and put them on bread or in savoury dishes. Use them as you would flax seeds.
The seeds contain Gamma-Linoleic acid (GLA) which is rarely found in plants, and this is an essential fatty acid which the body cannot manufacture. It is believed to have positive effect on the sex hormones, testosterone and oestrogen and to lower blood cholesterol levels and reduce blood pressure. It helps to prevent hardening of the arteries and so helps to keep the cardio-vascular system healthy. In some cases it has shown to be beneficial in the treatment of cirrhosis of the liver. 
Research is ongoing into the effects of GLA and the other constituents of evening primrose oil and the plant, as it has become a very popular remedy for the treatment of PMS/PMT and other menstrual and menopausal symptoms although there is scant scientific evidence to support its use. GLA is found in borage, bhang (hemp) and blackcurrant oils too. The oil is also used externally for eczema, and internally for rheumatoid arthritis. It does seem to be effective as an anti-inflammatory pain –reliever and in curing skin problems although trials have not been as detailed as they could have been, as some patients dropped out of the program.
Two studies have been done into the effectiveness of the oil on the symptoms of diabetic neuropathy, namely numbness in the legs and feet and tingling, burning, pain and lack of sensation. These were reported as being successful in that patients reported some easing of the symptoms, but it is too early to say categorically that GLA can help with these symptoms. The bark and leaves of the plant have astringent and sedative properties and have been used in traditional medicine systems to relieve whooping cough, gastro-intestinal problems and asthma. There is little medical evidence to support these uses however.
Native Americans used the whole plant in poultices to help heal bruising much in the same way as herbalists such as Culpeper used mallow and pellitory. They also used it as a wound healer or vulnerary. The roots of this plant are also edible and said to resemble those of salsify both in appearance and taste. They taste a little like parsnips too according to some people.
We have to wait and see if science can catch up with folk medicine and confirm or deny the benefits which many say they have experienced after using evening primrose oil.
