Washingtonia genus of palm trees includes only two species; the Washington fan palm (Washingtonia robusta), which is also called the Mexican fan palm, and the California fan palm (W. filifera). These trees are native to arid areas of California, Nevada, Arizona, Florida and northwestern Mexico, depending on the species. These palm trees grow up to 100 feet tall and have lifespans of up to 100 years. They are cold hardy to around 18 degrees Fahrenheit, making them appropriate for gardens as far north as USDA climate zone 8.