Washingtonia filifera

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Washingtonia filifera

Washingtonia filifera growing wild near Twentynine Palms, California

Conservation status

Near Threatened

Scientific classification

Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Liliopsida
Order:	Arecales
Family:	Arecaceae
Genus:	Washingtonia
Species:	W. filifera

Binomial name

Washingtonia filifera
(Lindl.) H.Wendl.

Washingtonia filifera (California Fan Palm, California Washingtonia, or Desert Fan Palm) is a palm native to the desert oases of southern California, southwest Arizona and extreme northwest Mexico. It grows up to 23 m (exceptionally 30 m) tall in good growing conditions and is the only palm native to California. The leaves have a petiole up to 2 m long, bearing a fan of leaflets 1.5-2 m long. When the leaves die they bend downwards and form a skirt around the trunk. The shelter that the skirt creates provides a microhabitat for many invertebrates. Washingtonia filifera can live from 80 to 90 years and its name honors George Washington, the first President of the United States.

Fan palms provide a habitat for Bighorn Sheep, Hooded Oriole, Gambel's Quail, Coyotes, and the palm boring beetle Dinapate wrightii (Coleoptera: Bostrichidae). Hooded Orioles rely on them for food and places to build nests. Both Hooded Orioles and Coyotes are integral part in seed distribution. Dinapate beetles can be problematic and chew through the trunks of palms. Eventually a continued infestation of beetles can kill a palm, opening up space for a new palm to grow.

Today due to urbanization, palm oases are disappearing. Increased agriculture has lowered ground water supplies and decreased the amount available in palm oases. This creates a threat not only to California's only native palm, but also all the organisms that rely on them in order to survive.

Planted California Washingtonias

The fruit of the fan palm was used by Native Americans. It was eaten raw, cooked, or ground into flour for cakes. The Coahuilla tribe used the leaves to make sandals, thatch roofs, and for making baskets. The fan palm was a valuable resource and the stems were used to make utensils for cooking.

It is widely cultivated as an ornamental tree throughout the lower elevations of California, Arizona, Nevada, New Mexico and extreme southwestern Utah, and as a novelty specimen in some cooler climates where it is not reliably hardy but may survive milder winters. It is also widely grown in the warmer parts of the Mediterranean region. The plants grow best in warmer Mediterranean climates with winter rain and dry summers. Specimens outside of Mediterranean climates do not grow as large, rarely exceeding 15 m. The plants are tolerant of some frost and the species is rated as hardy to USDA zone 8b; it will survive temperatures of -10 °C with minor damage, and established plants have survived brief periods of temperatures as low as -12 °C but with severe damage to the foliage.