The first Spanish explorers never saw our native California palms, but desert tribes knew them well. These huge fat-trunk, slow-growing natives are survivors of much earlier forests that died out eons ago due to climate change. All that remain are isolated groves at desert springs where there is still enough water to maintain the survivors. From these isolated stands come our entire fan palm population.
Here in Palm Springs, Calif., Washingtonia robusta became vital to the survival of Native Americans due to limited desert resources. They harvested the fruits and fronds and wood of the trees for food and building materials. The palms were as essential to desert people as buffalo were to plains tribes.
Despite our affinity for these great natives and their skinny brothers the very tall Mexican fan palm, there are important caveats. As the trees grow older, their unexpected behaviors should be known to everyone who owns or wants to own one.
1. Palm reproduction makes litter. Every year, a mature palm produces with long sprays of thousands of tiny white flowers that explode out of the foliage head. Once pollinated, petals are blown away in a snowstorm that litters the ground and the pool. The fruit is borne on long stems maturing into pea-sized black seed that rains down all around the tree. Seeds on paving are a hazard to foot traffic like ball bearings. Where they fall on soil, they germinate into a lawn of thin green blades. It's a maintenance nightmare to pull them all out of flower beds. Where it's a problem, flower stalks are trimmed back early to avoid the reproductive process altogether.
2. Palms are dangerous in high winds. Palms retain their dead fronds, the "skirt," which accumulates beneath the green living head of the palm. The native California palms hold their fronds indefinitely, well illustrated by those in the wild. However, occasionally they have been known to drop a full skirt in extreme wind events. Even a single wickedly-thorned stem can damage people, buildings, cars and landscaping, causing significant liability.
3. Palm skirts are alive with pests. In the wild, native palm skirts contain a whole ecosystem for wildlife, particularly rodents and birds. Over time, the skirt can become so large that whole colonies of animals reside there together. This isn't a problem away from homes, but in town, skirts will make neighbors very unhappy. Pigeons love to nest there, splattering the trunk and ground with white excrement. Rats nesting in the skirts are safe from coyotes. If the palm is close to the house, rats use it to access your roof and eventually get inside. Snakes even climb the palms to feed on baby birds and rats. Moreover, bats, potential carriers of rabies, roost in skirts, littering the ground with potentially toxic feces. After recent wildfires, palm skirts proved an important fuel for fast moving flames in urban areas.
4. Palms need access for trimmers. We love to plant around palm trees, but space should be reserved for tree trimmers and their ladders. When they cut fronds, they fall freely, crushing the plants around the trunk. Then the folks who pick up the fronds and carry them to the trucks stomp everything else. And if the palm is along your property line, all of the above can become your neighbor's problem, too.
5. Palms damage hardscape. A small fan palm today is a monster tomorrow because Washingtonias grow so fast. Damage to masonry is not so much the roots, but the rapid growth and expanding diameter. They are usually volunteers from seeds that fall into slots against wall foundations. These create so much pressure the wall may be cracked or pushed over.
There is nothing more elegant than a well lighted California fan palm specimen in the night garden. Growing them in small spaces, however, is a big responsibility. More than one gardener has quit and neighbors have become sworn enemies when big palms put people, their homes and cars in peril.