Hardiness: USDA Zone 9a: to -6.6 °C (20 °F) USDA Zone 9b: to -3.8 °C (25 °F) USDA Zone 10a: to -1.1 °C (30 °F) ... Washingtonia robusta is one of my favorite plants. This document is ENH-827, one of a series of the Environmental Horticulture Department, UF/IFAS Extension. It does not survive bedded-out in the garden in my climate Zone 8a, but I have been grwoing them in pots for years. They're a favorite with builders who want to give a finished look to a newly constructed home, and with homeowners who want more instant gratification. Scroll down to see what makes this palm unique. It is easy to transplant, fast growing and cold hardy. (Washingtonia Robusta) One of the fastest growing palm varieties available, the Mexican Fan Palm is great to buy in small sizes and incorporate into your South Carolina landscaping project. Very fast growing. Washingtonia robusta: Mexican Fan Palm1 Timothy K. Broschat2 1. The Washingtonia Robusta on the other hand is known as the Mexican Fan Palm. Prepare a planting area in full sun where your Washingtonia will be able to grow to 30 m (100 ft) tall without hitting power lines or nearby buildings. I love their huge branches and the fast growth-speed. ... being hardy down to about 20°F or USDA hardiness zone 9A. Washingtonia robusta, the 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, Texas, parts of the Canary Islands, Italy, Lebanon, Spain, and Réunion. Select Washingtonia robusta in an irrigated landscape and for the eastern U.S. Propagation is by seed. So far, I've killed my first two. The Mexican Fan Palm Tree, scientific name Washingtonia robusta, is very popular indoor and outdoor palm because of its striking appearance and cold hardiness which makes it a great choice for landscape in USDA zones 8b-11.. Size: Can get very large.In warm climates plants can grow up to 100 feet tall. The fast-growing, extremely hardy Washingtonia Palm can provide big tropical landscape appeal in a hurry. Washingtonia robusta. Also called Washington palm and Mexican Washington palm, the Mexican fan palm (Washingtonia robusta) is hardy in U.S. Department of Agriculture plant hardiness zones 9 â¦ The Mexican Fan Palm Tree, scientific name Washingtonia robusta, is very popular indoor and outdoor palm because of its striking appearance and cold hardiness which makes it a great choice for landscape in USDA zones 8b-11.This is a cold hardy, drought resistant and inexpensive palm that doesnât require a lot of maintenance. This is a cold hardy, drought resistant and inexpensive palm that doesnât require a lot of maintenance. They reportedly suffer and often die from root rot when irrigated. (Hardiness Zone 8b-10, guessing) Washingtonia (Washington Fan Palm) Washingtonia is a genus of only two, very tall, trunked, fast-growing species, named after who else, George Washington. Although it too is native to the Southwestern United States, it appears to do quite well in the Southeast. Washingtonia filifera is native to the southwest US and Washingtonia robusta to just south across the border in Mexico. Native habitat: Native to desert oases in southern California and the native palm of Palm Springs.Commonly planted in California and Florida. Washingtonia filifera is shorter, has a thicker trunk, and is better suited for planting in dry urban landscapes, such as in Texas. The 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).