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California Fan Palm

California Fan Palm (and Mexican Fan Palm)

Washingtonia filifera
Common Names: California fan palm, desert fan palm, American cotton palm, cotton palm, Washington palm, desert palm
Family: Arecacea (palm Family)

Habit: Stately and distinctive, this is one of the most widely grown palms in subtropical climates. It can grow 60 ft tall with a crown spread of 15 ft. The massive gray trunk is barrel shaped, ringed with old leaf scars and may reach over 3 ft. in diameter. It can have up to thirty gray-green palmate (fan-shaped) leaves, each 3-6 ft across that spread out to form a loose and open crown. The petioles (leaf stems) of mature palms are armed along the margins with curved thorns; those of young palms are largely unarmed. The individual leaflets are pendulous and swing freely in the wind. Abundant cotton-like threads on and between the leaflets persist even when the palm is mature. If old leaves are not removed, they form a continuous "petticoat" from the crown all the way to the ground. Branching flower clusters project out and often downward from the leaf crown. The bisexual blossoms are white and yellow and produce round red-black fruit about a 0.5” in diameter. The fruits of contain a single seed, approximately ¼” in diameter.

The very similar Mexican fan palm (Washingtonia robusta) and the California fan palm are closely related. They differ in subtle characteristics, and even palm experts have trouble telling them apart. The main difference is that that W. robusta is much more susceptible to freeze damage. Here are some distinguishing characteristics:

California fan palm W. filifera petioles (leafstems) of young palms are green and relatively unarmed (no thorns). W. robusta thorns are brown and distinctly thorny and the bottom of the base of the leaf blade has a bright tawny-colored patch. Crown of mature specimens of W. filifera has leaves in a loose and open arrangement, W. robusta crown is dense and compact. Leaflets of W. filifera are pendulous and swinging (not stiff), and the cottony threads are persistant. Leaflets of W. robusta are stiff and their cottony threads fall off with age. Trunk is barrel shaped and the palm rarely exceeds 60' in height. W. robusta is slender (slightly swollen at the base) and can get 100 ft. tall.

Washingtonia filifera, grows naturally in desert and arid regions, along streams and canyons, and in open areas where groundwater is present in southern California, western Arizona, and Baja California in Mexico.

Culture: It prefers full sun and even quite small specimens will thrive in full sun. It also grows well in part sun/shade. Once established it is drought tolerant, but it benefits greatly with regular watering. For optimal growth, soil should be moist with good drainage. Hardiness: USDA Zones 8 - 11. Established plants can withstand moderate frosts and freezes. Reports of cold hardiness for the California fan palm indicate it withstands temperatures to 15ºF. Don’t plant it in Zone 8 and colder without some protection. W. robusta will have freeze damage at much higher temperatures.

Uses: The California fan palm was an important resource for the Cahuilla Indians of Southern California, who called it maul. They used it for food, especially the fruit/nut that they ground up as flour or made into a mush. They also soaked the fruits to produce a sweet beverage and made jelly from the fruit. The spongy pith in the center was sometimes boiled and eaten and was called maul pasun or "heart of the palm." It was also used for construction (fronds for roof thatch), and leaves were stripped and used in various weaving applications. The hard seeds that fell after fruit pulp dried were the preferred fill for gourd rattles and were better than stones or other seeds. The Desert Cahuilla also preferred the fan palm for making sandals. Fire making tools as well as tinder were made from this palm.

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