Hooker's Evening Primrose. Oenothera elata Kunth. ssp. hookeri (Torrey & A. Gray) W. Dietr. & W.L. Wagner. Evening Primrose Family ( Onagraceae ), Hooker's Evening Primrose. Also Called: Western Evening-primrose. We wish to thank Wikipedia, the free encyclopedia for some of the information on this page. We share images and information with Wikipedia. Oenothera elata is a plant of the genus Oenothera known by the common name Hooker's evening primrose. Its subspecies include hookeri, hirsutissima and elata. It is native to much of western and central North America. The hookeri subspecies of Oenothera elata, native to California, can reach about 6 feet in height. The shade of its flowers varies from yellow to orange. Hooker's Evening Primrose is a biennial 4 to 6 feet high. It has stout reddish stems, light green lanceolate leaves, up to about 5 inches long and about 7/8 inch wide in its center. Its flowers are large, bright yellow, opening in the evening. It is naturally found growing along streams and in wet places. It is very showy and easy to grow. Well, we found a few of these plants growing in a small semi - dry stream bed in Yarnell, Arizona. After collecting seeds and trying to grow this plant for about four years, it finially grew like an unwanted weed! In other words, it really took off! We had noticed that this plant always grew and bloomed, about a month after our Arizona summer monsoon rains. This year has been one of our best monsoon rain seasons that we have had for several years. We have had about 3 inches of rain in about a three week period of time. The flowers open late in the day and then close the following morning. The flowers are up to 3 inches across and they have 4 broadly heart-shaped, yellow petals that turn a reddish orange color as they age and wilt. The flowers are nocturnal and very fragrant during the night. The flowers are soon followed by slender, green, 2 inch long seedpods that split open and spread the seeds.. The leaves grow along the stems and are green and lanceolate to elliptical in shape. The stems are slender and upright, and the plants are tall and narrow in shape. Quick Notes: Height: About 4 - 6 feet tall. Spreading out to about 18 to 30 inches wide. Flowers: Pedicellate flowers up to 4 inches across with 4 broad heart-shaped, yellow petals that turn a reddish orange color as they age and wilt. The wilt can take place in less than a day. Flowering Time: Mid July to Mid September. Leaves: Leaves are green and lanceolate to elliptical in shape, about 3 to 6 inches long and about � to 7/8 inches wide. Found: Native to Arizona & California. Found throughout different elevations in Arizona, in all but 5 counties. The USDA claims it is only native to the USA in (CA). But thats not true. Hardiness: USDA Zone 8b: to -9.4 �C (15 �F) Soil pH requirements: 6.1 to 6.5 (mildly acidic) 6.6 to 7.5 (neutral) 7.6 to 7.8 (mildly alkaline) 7.9 to 8.5 (alkaline) Sun Exposure: Full Sun Elevation: 4,886 feet. Habitat: Near water or low spots where water gathers. Riparian areas. Semi - dry streambeds. Miscellaneous: Flowering Photos Taken July 30, 2012. Yarnell, Arizona.

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