Flowers. Saltillo Evening Primrose. Oenothera stubbei.	Flower. Saltillo Evening Primrose. Oenothera stubbei.

Saltillo Evening Primrose. Oenothera stubbei, Evening Primrose Family ( Onagraceae ), Saltillo Evening Primrose. Also called Baja Evening Primrose, Chihuahuan 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. An evening blooming, perennial, groundcover, with bright green leaves in rosettes, that becomes a dark green mat about 5 inches high and 4 feet wide. Its stems take root along the ground, forming offset plants. Its yellow 2 inch flowers bloom in the spring and sporadically during the rest of the year. The flowers bloom at night, wilting quickly during the early morning. It takes full sun to part shade, but prefers afternoon shade and a little more water than most xeric-adapted primroses. Quick Notes: Height: Up To 5" tall, and up to about 4 feet in diameter. Flowers: Flowers yellow 2 inch. Flowering Time: April - September. Leaves: Leaves are in a basal rosette. Green, fuzzy leaves. Found: Native to the Chihuahuan Desert of northeastern Mexico; which covers the northern half of the Mexican state of Chihuahua, most of Coahuila, the north-east portion of Durango, the extreme northern portion of Zacatecas and some small western portions of Nuevo Le�n. The altitudes of the Chihuahuan Desert range from about 1,969 � 5,495 feet in altitude. As a result, it tends to have a slightly milder climate in the summer, with winter weather varying from relatively mild to quite cold depending upon both altitude and the ferocity of northerly winds. Precipitation is somewhat more abundant than most of the southern Great Basin, the Sonoran, and Mojave deserts, with much of the rain falling during the "monsoon" of late summer. The mean annual precipitation for the Chihuahuan Desert is 9.3 inches. Snowfall is scant except at the higher elevation edges of the desert. We see Oenothera stubbei growing throughout lower to higher elevations in Arizona as a landscape plant. Hardiness: We have read one report from a gardener in Zone 6a who has grown this plant. The Arizona Municipal Water Users Association says it is hardy to 15 �F. USDA Zone 9a: to -6.6 �C (20 �F) USDA Zone 9b: to -3.8 �C (25 �F) USDA Zone 10a: to -1.1 �C (30 �F) USDA Zone 10b: to 1.7 �C (35 �F) USDA Zone 11: above 4.5 �C (40 �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. No reflected sun. Some Shade Elevation: 0 to 2,900 feet In Arizona. In its native habitats, it is usually between 1,800 to 2,300 feet. Habitat: It occupies open, sandy washes to rocky flats, bajadas, roadsides, and playas. Miscellaneous: An ideal xeriscape landscape plant at low elevations in Arizona.