Trailing Four O'Clock. Allionia incarnata villosa, Four O'Clock Family ( Nyctaginaceae ) , Trailing Four O'Clock. Also called Trailing Windmills or Herba de la Hormiga. We wish to thank Wikipedia, the free encyclopedia for some of the information on this page. We share images and information with Wikipedia. A perennial herb. The flowers on a single cluster mature all at once in the morning and then shrival by the next day. There are three sub species of Allionia incarnata in Arizona and two on the Sonoran Desert. Quick Notes: Height: About 10 inches to 36 inches high. Spreading out to about 3 foot wide. Flowers: The flower appears to be a brilliant pink to majenta color, irregular, about 1" long, inflorescence consisting of three tightly clustered zygomorphic flowers. Flowering Time: March to October. Leaves: The leaves are simple, entire, estipulate, and opposite. They are also thick and hairy. Found: Native to Southern & Central Arizona, & New Mexico, & Sonora, Mexico. Hardiness: 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 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 Elevation: 0 - 6500 Feet. Habitat: On roadsides, sandy plains, rocky sides of stream beds, and mesas. Miscellaneous: Flowering Photos Taken April 25, 2005 Date Creek, Arizona and Apache, Lake, Arizona April 17, 2009.