California fan palm (Washingtonia filifera)
The California fan palm has a moderate growth rate and can reach a mature height of 60 feet with a trunk diameter that can be up to a 36 inches. They will hold their brown frond stalks for many years, forming a skirt of thatch. When pruned, frond stalks bases form a distinctive series of vees along the length of the entire trunk. When the lower portion drops off with age, the clean trunk is smooth and gray. They produce large fan shaped fronds that have a grayish green color with cotton like fibers hanging from leaf tips. They produce cream white flowers on 9-15 foot long stalks followed by brownish-black fruit. A mature palm will produce multiple inflorescences through the year. They are typically found in the warm climate and the only palm tree native to western North America. Suitable for 3’ minimum parkways, medians or cutouts. Good for street sides, medians, parks, lawns, in groups and as accent trees. Commonly planted throughout Southern California as an avenue tree. They susceptible to diamond scale and pink bud rot in the coastal zones with less occurrence in the desert climates.
California fan palms have the natural ability to withstand wild fires and are not usually killed by the burning of thatch or by repeated burning. Although repeated burning can decrease their trunk diameter, they are seldom burned off by fire. Studies have shown that the fibrous trunks are difficult to ignite and almost impossible to flame. California fan palms actually benefit from fires with increased seed production and seedling growth.
© Walter Warriner Consulting Arborist
