Brittlebush. Encelia farinosa, Sunflower Family, ( Compositae ), Brittlebush. Also Called: White Brittlebush, Incienso, hierba del vaso, cotx. We wish to thank Wikipedia, the free encyclopedia for some of the information on this page. We share images and information with Wikipedia. Other names for Brittlebush include "incienso," and "hierba del vaso" (Spanish) and "cotx" (Seri). The Spanish name is because the dried sap was burned by early Spanish Missions in the New World as incense. Quick Notes: Height: Up To About 1 1/2 to 3 1/2 feet tall. Flowers: Yellow flower heads are 1 to 1 3/4 inches across, with 20 to 50 bright yellow ray flowers ("petals"). These do not drop off, but are persistent and become faded, papery, and turned downward in age. The flower heads are mostly borne singly at the tips of the stems and branches on long naked stalks, 4 to 8 inches long. Each head produces at least 100 achenes, which are rodshaped, about 1/8 inch long, light brown, with many longitudinal nerves on the surface. Flowering Time: Mid March - November. Leaves: Soft, woolly leaves are alternate, clustered largely at the base of the plant and divided into irregular close set lobes, or some are divided again. The upper leaves are few lobed, or may be narrow and smooth edged. Found: The USDA claims that Encelia farinosa is native to the USA (AZ, CA, HI, NV, UT). In Arizona it is native to all counties except Navajo, Apache, Yavapai, Cochise, & Santa Cruz. In Mexico it is native to the states of Baja Norte, Baja Sur, Sinaloa, & Sonora. Found throughout lower elevations in Arizona. Hardiness: 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) 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 to 5,000 feet. Habitat: Brittlebush is a native range weed growing on sandy or gravelly soils. A most attractive and abundant plant along roadsides, plains, and mesas. An ideal xeriscape landscape plant in Arizona. Miscellaneous: Flowering Photos Taken March 16, 2005. Near Lake Pleasant, Arizona.