Oenothera biennis - Herbaceous biennial. 90-120 cms height, 60 cms width. Medicinal north American herb. Full sun to part shade. Fragrant yellow flowers, which at the start of the flowering season only open in the evening, but as the season progresses the flowers also open in the day, but have no scent until the evening. Flowers in a constant succession through summer and autumn. Cut back after flowering.  Grows in poor to moderately fertile well drained soil, in an open airy position. Established plants are drought resistant. Not frost tender. Seeds are an excellent food source for birds. Flowers attractive to bees, moth’s butterflies and pollinating insects. Whole plant is edible. A yellow dye is obtained from the flowers. A good plant for naturalizing in a wild garden or in mass plantings. Will self seed, seedlings can be carefully transplanted to other locations.