Oenothera biennis is a species of Oenothera, an herbaceous flowering plant native to America which can be found from Newfoundland to Alberta. Common names for the Oenothera biennis include; evening primrose, evening star, suncups and sundrops.
Oenothera biennis is a biennial (as the name suggests) or short-lived perennial herb producing strong fleshy roots and a basal rosette of lance-shaped leaves in the first year. In the second year, the stems grow and develop beautiful yellow, tubular flowers.
The "evening" in the name relates to the fact that it is a night blooming plant that will produce a succession of short lived blooms from late spring until mid-summer if the dead flowers are removed promptly. The flowers are hermaphrodite, produced on a tall spike and only last until the following day. The flowers open-up visibly fast, every evening producing a lovely spectacle. Their flowers open in the evenings for night flying moths to pollinate them. The Evening Primrose isn't a "primrose," a name best applied to the genus Primula.
The Evening Primrose has eye-catching bright, lemon-yellow, cup-shaped, flowers that measure 2 to 3 inches across and have a mild lemon-scented fragrance. The glossy rich green lance-shaped leaves surround spreading red stems. The seed pods are 4-winged and 2 to 3 inch long and are often used in flower arrangements. It has a spreading growth of 6 to 12 inches in height and 2 to 3 feet wide. The evening primrose is a great plant for borders and rock gardens. It is hardy in zones 5 to 8.
The Evening Primrose prefers to be grown in full sun but will tolerate some light shade in the afternoon.
It is an easy plant to take care of; it spreads enthusiastically and might need control. The evening primrose attracts butterflies and birds.
Evening primrose extracts were used medicinally by both Indians and early settlers. The oil from the seed of the evening primrose plant is a gamma-linolenic acid, which is an omega-6 essential fatty acid. The oil is used to treat skin disorders such as eczema, psoriasis, and acne. Evening Primrose oil is also used for treatment of many ailments among them; rheumatoid arthritis, osteoporosis, premenstrual syndrome, chronic fatigue syndrome. In foods, evening primrose oil is used as a dietary source of essential fatty acids.