The Palm Society--Northern California Chapter

Northern California Chapter
Palm Society
Lakeside Palmetum
Species List
Additional Pages

More places to see palms
Seeds and such

Washingtonia filifera
Washingtonia robusta

Washingtonia robusta

Common name: Mexican Fan Palm *
Native to: Mexico Baja California, Sonora
Mature height: 100 feet
Mature spread: 12 feet
Growth Habit: solitary
Leaf type: palmate
Washingtonia robusta

photo by: Dennis Valdez
Private Garden


Most commonly known as Mexican Fan Palm and has other common names such as the Sky Duster and the Cotton Palm. Mature Washingtonia robusta with their tall slender trunks and compact crown silhouetted against the Western sky are the quintessential California scene. The two species of Washingtonia (robusta and filifera) are very closely related but quite distinct in appearance. Mexican Fan Palm has deep green leaves divided 1/3 into the blade usually with a tawny patch on the underside at the juncture with the petiole which is viciously armed with hooked reddish-brown thorns even at an early age. Trunks are flared at the base and can retain dead leaves in a "petticoat" extending to the ground for up to fifty years or longer before they naturally abscise and expose their slender grey trunks. Although similar but distinct in appearance, the two species differ radically in cultural requirements. The Washingtonia robusta is native to coastal Baja and Sonora is extremely drought tolerant and will even grow on California’s cold fog-shrouded northwest coast. Grows well in full sun from seedling size and will eventually tower above all other canopy. However, native to the interior desert regions of California, Arizona and Sonora, is utterly intolerant of damp coastal conditions and actually requires a dry regime to thrive and best if irrigated deeply on a monthly basis. Leaf damage will occur at 20°F, but recovers quickly; hard freezes may completely kill even mature specimens. This palm is sometimes considered as a weed by some people due to their abundance, rapid growth rate (up to 6 ft per year when young) and high maintenance thatch. Propagation is only possible by seed, and hybridizes readily.

Washingtonia robusta

photo by: Dennis Valdez
Jim Denz Garden
Los Altos
Washingtonia robusta

photo by: Dick Douglas
Dick Douglas Garden
Walnut Creek
This species in the garden:
Growth rate: very fast
Sunlight: full sun
Water: moderate
Cold Tolerance: 20° F
Seed or plant availability: common

Send mail to for questions on palms.
© 2004 by the Palm Society, Northern California Chapter