Washingtonia robusta or Mexican Fan Palm is a massive palm native to Southwest Arizona, Southern California and Northern Mexico. In nature, these palms will reach up to 100 feet (>30 m) tall with slender gray trunks. Leaves are bright green, costa-palmate, with well-armed petioles. Leaves will reach up to 5 feet (1.5 m) long and up to 4 feet (1.2 m) wide. Trees are planted as street trees in California and other Mediterranean-like climates. They are fast growing and make good container palms while they are young. The palms are hardy in the landscape in USDA zones 9-11.
Blooming: Our palms are 3 years old and have yet to bloom.
Culture: Washingtonia robusta need full sun to light shade, preferring a well drained soil mix. In the greenhouse, we use a soil mix consisting of 1 part peat moss to 1 part loam to 2 parts sand. The palms are well watered and allowed to dry before watering again. We fertilize them once a month with a balanced fertilizer diluted to 1/2 of the amount recommended on the label. In the landscape, the palms are very drought resistant, but will grow faster with regular watering and fertilizer. Our specimens at 3 years old have reached a height of 5 feet (1.5 m) tall. During the winter months, water is restricted and fertilizer is not used during this period.
Propagation: Washingtonia robusta are propagated from seed. Seeds germinate in 30-60 days after sowing.
Washingtonia robusta was featured as Plant of the Week July 31-August 6, 2009.
Guide to Past Plants-of-the-Week:
Cal's Plant of the Week was provided as a service by the University of Oklahoma Department of Microbiology & Plant Biology and specifically the late Cal Lemke, who used to be OU's botany greenhouse grower and an avid gardener at home as well. If the above links don't work, then try the overview site. You may also like to look at the thumbnail index. ©1998-2017 All rights reserved.