The evening primrose is of interest because it contains an unusual fatty acid - gamma linolenic acid (GLA). GLA is a compound which is used to treat a number of diseases such as breast pain and eczema. The best source of GLA is the oil from the seeds of the evening primrose.

The evening primrose family originated in Central America and evolved into a number of closely related species as it migrated into the North American continent. With the discovery of North America by Europeans, it rapidly spread as a stowaway and by deliberate introduction to many other parts of the world.

It normally grows as a biennial, that is to say, it germinates in one year and flowers in the next. In the first season, it produces a rosette of leaves and then overwinters in this form. In the second year it produces a central stem ('bolts') and flowers in late June. Each flower lasts only one day and the zone of flowering moves progressively up the stem. The pods then ripen over a period and when they are mature, the plant dies.

As a wild plant, the evening primrose has a number of problems for the farmer. These have been tackled through research in plant breeding and agronomy as well as entomology and pathology, aiming to improve the quality, reliability and yield (cost) of the crop.

Three examples of these problems are seed dormancy, in which the seed may lie in the soil for many years before germinating; lack of uniformity; and the shedding of seed from the pods before harvest. These have all been successfully tackled and the evening primrose is grown successfully in a range of countries using modern methods and equipment.

As a result of this work, cost-effective and reliable supplies of evening primrose oil are available for the alleviation of the suffering caused by disease.