Washingtonia filifera, commonly known as the California fan palm, cotton palm or desert fan palm, is a flowering plant in the family Arecaceae, native to the far southwestern United States and northwestern Mexico. It typically grows 30–50 feet (9–15 m) tall and 1–2 feet (0.3–0.6 m) wide, with a sturdy, columnar trunk and waxy, fan-shaped (palmate) leaves. As a monocot, it is evergreen and exhibits a tree-like growth habit.
It is the only palm species native to the southwestern United States, forming groves around perennial water sources in the Colorado, Mojave, and Sonoran deserts. These stands provide critical habitat for wildlife and were historically used by Indigenous peoples of the region for food, shelter, and materials. Today the California fan palm is widely planted as an ornamental tree in arid and subtropical climates, though wild populations face pressures from groundwater decline, and habitat alteration.
In California, where the majority of its native groves occur, the species forms iconic desert oases such as the Oasis of Mara in Joshua Tree National Park, the Thousand Palms Oasis in the Coachella Valley Preserve, Lost Palms Oasis, and Fortynine Palms Oasis. Outside California, notable populations are protected at Castle Creek in Arizona's Bradshaw Mountains, the Hassayampa River Preserve, and Kofa National Wildlife Refuge.
Description
Washingtonia filifera var. filifera is a stout, single-stemmed palm that typically grows 30–50 feet (9–15 m) tall. The trunk is usually 1–2 feet (0.3–0.6 m) thick, brown when exposed but often concealed beneath a dense skirt of persistent dead fronds. If left untrimmed, this thatch may extend the full length of the trunk, providing insulation against both heat and cold, reducing fire damage, and creating shelter for small animals.
California fan palms (Washingtonia filifera) with dense thatch skirts, growing alongside saguaros (Carnegiea gigantea) at Alkali Spring in the Castle Creek area, Yavapai...
