General: Tall Evening Primrose (Oenothera elata) is an upright, biennial forb that opens large, yellow flowers in the evenings of its second year. The plant grows to 3-4-ft tall, which is much taller than most of our Evening Primroses. The stem is stout and often reddish. The leaves are several inches long, narrow, and often with wavy margins. The flowers are large, with petals spreading to 3-4 inches across. The hypanthium (the tubular stalk behind the petals) is 20- to 50-mm-long.

Tall Evening Primrose is superficially similar to Longstem Evening Primrose, but in the later species, the hypanthium is much longer (60- to 135-mm).

Tall Evening Primrose is an uncommon component of vegetation communities in moist meadows and woodlands from sea level to 9,000 ft elevation. Around Las Vegas, look for Tall Evening Primrose outside the Mojave Desert in places such as northern Nevada and the Grand Canyon.

Family: Evening Primrose (Onagraceae). Also called Hooker's Evening Primrose.