Oenothera biennis
Evening Primrose is a biennial to 1.5 metres tall. Producing large yellow flowers open in evening. Whole plant is edible and it's main medicinal uses is for extracting the oil which is said to ease skin conditions such as acne, rheumatoid arthritis, weak bones, high cholesterol and many others.
Likes good well drained soil in sun to part shade position.
Sow Autumn - Winter.