A Guide To Local Palms

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  • Post last modified:July 12, 2012
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Swaying gently in the breeze on the steep banks of Swami’s surf outlook or standing tall like soldiers going off to war in single file along Coast Highway 101, the Washingtonia Robusta can be found almost anywhere here in Southern California.  Commonly known as the “Mexican fan palm,” I used to hate this tree because of its rapid growth rate and resulting mess. Tree chippers can’t make clean mulch out of the old dead fronds and the blades dull quickly after running a few trees worth of material through them. This makes the resulting chips even coarser and less usable.  It is only suitable for the landfill and a hefty dump fee.

But, having lived with these trees around me for so many years, I have grown to love the sound of the wind coursing through them.  Their brilliant canopies reflect the sun and their steady promise to stay green and make shade for the grateful understory plants and the people celebrating their oasis.

One unique thing about the palm kingdom is that there is really only one species out of more than 1,000 types of palms truly native to California. This tree would be the sister to the Mexican fan palm, the Washingtonia Filifera or California fan palm. It is a Borrego local and supposedly originated at the top of Palm Canyon at the base of the shear canyon walls where a fresh water spring cascades down between polished boulders and washed desert sand.

The differences between these two trees are great, but to the casual observer are difficult to ascertain. Our local Mexican fan palm is much more slender and grows quickly in comparison to the Filifera. The desert palm has gray green foliage, less ferocious hook thorns on its fronds and does not tolerate moisture very well.

Near the beach, the moist air from the sea plays havoc with the Washingtonia Filifera and encourages a black sooty tar. This hard-backed spotty fungus attacks the surface of the fronds. To be fair, they just don’t do well by the coast. In Vegas, or Phoenix however, they do great. There really is nothing like rows of 40- to 50-foot California fan palms standing straight up with fat trunks and healthy green canopies delineating the boulevard. Ton per ton, they definitely give the Phoenix Canariences a run for its money when it comes to sheer size.

In more ways than one, our local Robusta is a flexible character. It can tolerate the British snow and winters outside down to 20 degrees Fahrenheit. Hailing from Sonora in mainland Mexico and Baja California, it also loves great heat, drought and yes, copious amounts of water.

In fact, the state in accordance with environmentalists has placed this tree on the noxious intruder list and has instituted eradication procedures in wetland areas. In other words, these trees can grow in standing water along drainage ditches and salt marshes.
The interior of these palms is comprised of many vascular fibers woven together giving the tree incredible flexibility in high winds. Most homeowners looking up at their Mexican fan palm dancing in the wind become fearful that their tree will break or fail. Not to fear, the Robusta (as long as it is healthy) will never go over and can be pulled almost horizontal by a crane before it will fail. If the top of a Mexican fan palm is cut off as the linemen do so often to clear the power lines, the trunk will rot internally, fold and fall over. Not a pretty sight and definitely a dangerous practice.

The Robusta is so tough that even an intense skirt fire racing up the trunk of the tree will not kill these magnificent trees. After the Witch Creek Fire, many of the palm groves at Evergreen Nurseries were completely burnt. Now, they have all returned to full vigor and have pushed completely new heads.

My suggestion for planting the Robusta is to place the tree in groups of three to four. Plan for huge overall future height and canopy and give space between the baby palms and any nearby patio, wall or structure. As the tree grows, and so will the diameter of its base.