Blue Euphorbia. Euphorbia rigida, Spurge Family ( Euphorbiaceae ), Blue Euphorbia. Also Called: Upright Myrtle Spurge, Gopher Plant, Gopher Spurge, Milkweed, Euphorbia biglandulosa. We wish to thank Wikipedia, the free encyclopedia for some of the information on this page. We share images and information with Wikipedia. Blue Euphorbia is a rather beautiful plant from the rocky slopes and scrub of the eastern half of the Mediterranean. It has attractive, stiff, narrow pointed, glaucous leaves, sometimes flushed with pink or purple, it bears from very late winter to the early spring, large heads of of chartreuse bracts with bright yellow flowers. Quick Notes: Height: Height about 1 - 2 feet. Spreading about 2 - 4 feet. Flowers: Clusters of chartreuse bracts borne at the tips of stems, each bract enclosing two to three flowers. Flowering Time: Mid December - March. Leaves: Evergreen, growing spirally around the stems, pointed, wedge-shaped, glaucus-olive green. Found: Native to Mediterranean Europe, Turkey , Syria , the Caucasus , North of Iran , Morocco. The USDA claims it is native to the USA (CA). It is also native to Mexico in Baja Norte, & Baja California. We see it throughout lower elevations in Arizona as a landscape plant. Hardiness: Some people claim it will grow past USDA Zone 9a: to -6.6 �C (20 �F). But, we doubt that. USDA Zone 7a: to -17.7 �C (0 �F) USDA Zone 7b: to -14.9 �C (5 �F) USDA Zone 8a: to -12.2 �C (10 �F) USDA Zone 8b: to -9.4 �C (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 Partial Shade Elevation: 0 to 3,600 feet In Arizona. Habitat: Well-drained, sandy, poor to moderately fertile soils. A Xeriscape Landscape plant. Miscellaneous: Photos Taken At Westbrook Village, Peoria, Arizona. March 16, 2006. An ideal xeriscape landscape plant in Arizona.