|Mexican Washingtonias planted in Los Angeles County Arboretum and Botanic Garden|
Washingtonia robusta (Mexican fan palm or Mexican washingtonia) is a palm tree native to western Sonora, and Baja California Sur in northwestern Mexico. It is reportedly naturalized in Florida, California, Hawaii, parts of the Canary Islands, Italy, Spain, and Réunion,
Washingtonia robusta grows to 25 m (82 ft) tall, rarely up to 30 m (98 ft). The leaves have a petiole up to 1 m (3.3 ft) long, and a palmate fan of leaflets up to 1 m long. The inflorescence is up to 3 m (9.8 ft) long, with numerous small pale orange-pink flowers. The fruit is a spherical, blue-black drupe, 6-8 mm (0.24-0.31 in) diameter; it is edible, though thin-fleshed.
Like the closely related Washingtonia filifera (California Fan Palm), it is grown as an ornamental tree. Although very similar, the Mexican Washingtonia has a narrower trunk (which is typically somewhat wider at the base), and grows slightly faster and taller; it is also somewhat less cold hardy than the California Washingtonia, hardy to about -8 °C (18 °F).
Field research conducted on Washingtonia robusta in its native habitat on the Baja California peninsula concluded that its potential longevity may exceed 500 years.
Supporting research by Barry Tomlinson and Brett Huggett states that there is "evidence for extreme longevity of metabolically functioning cells of considerable diversity in palm stems." Many of the iconic "sky dusters" of Los Angeles that have survived the chainsaws of progress are documented in photography from the 19th century.
Unlike Washingtonia filifera, which has been cultivated as far north as southern Oklahoma and Southwestern Utah, the Mexican fan palm is normally grown in the desert southwestern United States, in areas such as California, Arizona, Southern Nevada, and southern New Mexico as well as Dallas Texas. It also cultivated in the coastal areas of south Atlantic states and Gulf Coast, including extreme southern North Carolina, coastal South Carolina, southern Georgia, and Florida. Along the Gulf Coast, Mexican fan palm can be found growing along the Florida west coast westward to southern Texas.
Flowering palm in Chandler, Arizona
Arizona State University's Palm Walk
Species in Venice Beach, California
Species line Santa Clara Street in San Jose, California
Oldest palms in Los Angeles, planted circa 1875.