Hooker’s evening primrose (Oenothera elata) is a tall, herbaceous plant in the evening primrose family (Onagraceae). It is characterized by its showy bright yellow flowers with four heart-shaped petals and by elongated seedpods that develop below the base of the petals.
As its name implies, Hooker’s evening primrose has nocturnal flowers that open in the evening and wither the following morning. It is primarily pollinated at night by sphinx moth, but may be visited by other insects near dawn and dusk.
Hooker’s evening primrose is native to California. However, it is also found elsewhere in western North America, growing along streams and in moist places in many plant communities.