Desert Wishbone Bush. Mirabilis bigelovii, Four O'Clock Family ( Nyctaginaceae ), Desert Wishbone Bush. Also called: Wishbone Bush, Mirabilis laevis. We wish to thank Wikipedia, the free encyclopedia for some of the information on this page. We share images and information with Wikipedia. Quick Notes: Height: A herb, about 12 - 24 inches high. Flowers: The 1/2 - 3/4 inch pale white to light pink funnel shaped flowers without petals (the sepals look like petals) bloom at the ends of weak, sticky stems which form "wishbone" patterns. Flowering Time: March - May. Leaves: The leaves are simple, smooth - edged, oval to heart - shaped, hairy, up to about 1 1/4 inches long. Found: Native to Southern & Central Arizona, & New Mexico, & Sonora, Mexico. Found throughout lower elevations in Arizona. Hardiness: USDA Zone 9b: to -3.8 �C (25 �F) USDA Zone 10b: to 1.7 �C (35 �F) USDA Zone 11: above 4.5 �C (40 �F) Soil pH requirements: 6.6 to 7.5 (neutral) 7.6 to 7.8 (mildly alkaline) 7.9 to 8.5 (alkaline) Sun Exposure: Full Sun Some Shade Elevation: 0 - 2,500 Feet. Habitat: On roadsides, sandy plains, rocky sides of stream beds, and mesas. Well drained soil is preferred. Miscellaneous: Flowering Photos Taken May 1, 2003. Castle Creek, Arizona. The flowers wilt by late in the morning.