Saturday, August 22, 2015

"Day of the Triffids" or "Monolith Monsters" ? (Mexican Fan Palm - Washingtonia robusta)

Korny 1950s Sci-Fi flicks beautifully illustrate some of today's dangerous landscape practices that have gotten out of control


Courtesy of Civano Nursey, Tucson, Arizona

Mexican Fan Palm (Washingtonia robusta)

Well, not exactly "Day of the Triffids" or "Monolith Monsters", but you wouldn't know that by some of the bad public relations they are receiving lately. And yet it is fair to say there are certain maintenance challenges and wildfire dangers that people should be aware of and educate themselves about before installing them in their landscape. A century ago when it came to landscape palms in California, two were the most prominent, the native California Fan Palm (Washingtonia filifera) and the Canary Island Date Palm (Phoenix canariensis). Both have pretty much fallen out of favour with Southern California landscapers and gardeners. Why ? Well, the date palm is messy and when young a major challenge when it comes to space. Also extremely difficult to prune or trim because at the base of the palm frond where it's attached to the tree trunk are some of the most vicious spines you'll ever not want to tackle. The native California Fan Palm is much cleaner maintenance-wise, but it also when mature after some years will also produce date fronds, though much smaller dates. It does have one advantage in that it is much slower growing, but that is also why it was replaced by the Mexican Fan Palm which is much faster growing and provides instant landscape for the Nurseries, landscapers and homeowners who want instant tree. Nobody has patience any patience anymore. Today, it's almost impossible to find a nursery that carries the California Fan Palm and even many native plant nurseries don't carry them or if the do, they are limited and sell out quickly. And while the Mexican Fan Palm has become the typical landscape symbol and taken over the California popularity contest, there are also some major problems with this palm tree.

The Monolith Monsters (1950s monster invasion movie)

image: Desert USA
It was 1957 in a desert town where a geologist found a mysterious rock which grew bigger and propagated itself when it came into contact with water. Towards the end of the movie these monolithic black crystal spires move down this canyon headed for the town. Now where do you suppose these writers got such a crazy idea for such a Sci-Fi script ??? Oh yeah, it's a common sight on the desert side of mountain ranges in SoCal. You can even visit the Palm Springs name sake, Palm Canyon as seen in the photo at right. There are however three negative things to be said about the presence of the Mexican Fan Palm in Southern California's landscape. First it easily escapes the urban landscape and naturalizes into the wilds of Southern California. Second, because of the ease of naturalizing, it has become so invasive that it has smothered many native riparian habitats which effects all the native wildlife. Third, it has become a major component of wildfire spread and loss of homes. This palm tree explodes like a Roman Candle and over a period of 30 minutes while burning can create innumerable sparks or embers which may travel as far as a mile depending on the extreme high wind conditions causing spot fires ahead of the main fire. It and other non-native trees like Salt Cedar or Tamarisk have changed the physical barrier of a riparian habitat which while not fire proof, always could slow a fire down, but it's presence acts as a sort of transportation bridge to newer drier vegetation on the other side of a valley. This naturalizing ability was mentioned a while back in an article in the L.A. Times:
LA Times: "When many of us think of Los Angeles, there’s a palm in the picture. That palm is likely Washingtonia robusta, the Mexican fan palm."
But the region’s palmy past is seeding trouble. “Most of the dates fall nearby,” says licensed herbicide applicator Bill Neill, “but some will eventually go down the storm drains into the river channels.”
And there is another serious problem with this palm so easily invading the infrastructure of Los Angeles, San Diego and other Southern California city's storm drain outlets.
Mexican fans also reduce the flood-control capacity of the L.A. River (and others). Any vegetation will slow water flow, but the U.S. Army Corps of Engineers rips out invasives before it touches native plants. “Willows don’t burn easily,” says Corps ecologist Carvel Bass, “but fan palms and arundo do, and they don’t contribute to the habitat in any positive way.”
While the Mexican Fan Palm does have some wonderful qualities as an ornamental in the landscape, there are those fire safety issues which everyone should understand. They seriously need to have their dried coat of fronds trimmed by professionals. They are dangerous for rookie inexperienced homowners to do this themselves. It's dangerous also for the professionals, this is why so many of them die each year and their business insurance is insanely high. Therefore, watch this video below which is about eleven minutes long and illustrates the tree's ability to create 1000s upon 1000s of burning embers as high as 100 feet in the air and during horrific Santa Ana wind events that are common in Southern California, can blow as far away as a mile and start spot fires, or even house tract in neighbourhoods on fire as was the case with the Witch Creek Fire in 2007 which burned numerous homes in the Rancho Bernardo area of San Diego. On December 25th, 2014, LAFD Engine 68 on scene at Mansfield Avenue & Venice Boulevard in Mid-City encountered a palm tree on fire up against high-tension power lines. Unable to put water directly on the fire due to the high voltage, they requested Department of Water and Power to shut them down. With high winds gusting up to 45 miles per hour fanning the flames, millions of embers flew across Venice Boulevard, threatening cars, businesses and other palm trees down the block. An additional Task Force was called in to handle the flying ember problem that started to collect and pool around the edges of buildings and roof-tops. Firefighters knocked down the burning embers with hand-lines at trash piles across the boulevard and in the alley behind other properties. Eventually Engine 68 set up a stream with its “wagon battery” below the power lines, knocking down most of the fire. 


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How Mexican Fan Palm has taken over the city of San Diego, wildlands between housing tracts
I've always wanted to do historical documenting of this tree's spread, mostly because I've never found where anyone else ever has. That is to document the massive invasive takeover within the city limits of San Diego, California by the Mexican Fan Palm, not only in wet riparian stream beds, but also up dry washes and canyons where water traditionally hasn't always present or available. At least before housing and human water wasting changed all of that. Again, thus far I've never seen or heard any authority in San Diego County mention any of this before.

Google Earth: Interstate 8 Freeway just west of College Avenue

Image: Google Earth
These two photo locations above and to the right are the Interstate 8 freeway and College Avenue overpass. The photo above from Google Earth is just west of the College Ave overpass. The photo to the right is on the south side of I-8 and exists to San Diego State University. When I was a small kid in the early 1960s, those palm trees in the creek bed didn't exist. I know because almost few times a month our family often drove back and forth over this route on our way to the beach or to visit a great uncle who lived in Allied Gardens off Navajo Road. However, one day in the middle 60s, I noticed some young palms on the north side of I-8 in the top photo. Also a couple on the south side where the creek bed routed from. Further upstream all the way into the city of La Mesa, they kept getting even bigger. Over the several next decades they all just got bigger and more numerous. Further up the road it was obvious where the source of the seed came from. 


Image: Google Earth

This is the the old former Alvarado Trailer Park on Alvarado Rd in La Mesa which is now called the San Diego RV Resort. Before the change, I seem to recall the old park as going down hill, like so many other older trailer parks in that county which originally started out as roadside Auto Kamps for travelers later converted to permanent residential trailer parks. But back in those early days, almost every single one of them planted a Mexican Fan Palm in each small lot or trailer space. This Resort now has greatly reduced and thinned out considerably the Mexican Fan Palms from what it once was. When I was head landscaper for the property management company in San Diego before moving here to Sweden, one huge mobile home trailer park in El Cajon on Bradley Avenue was also loaded with these palms. The owner of that Mobile Home Park was also a board member of the San Diego Wild Animal Park and years back donated many of them in the early development of the San Diego Wild Animal Park which has since changed it's name to Safari Park. That old Mobile Home Park still has some, but not as it originally did. They are a maintenance nightmare and expense to have professionals come out which is the only was to have it done. But that Trailer Park up on Alvarado Rd in La Mesa was definitely the source of seed for everything down stream. These trees over a life time can produce millions upon millions of seeds. There is something more interesting that most folks living there probably don't know about that first photo next to Interstate 8, although many do, especially the college kids. It's a location below those palms along the freeway which drops off dramatically and is named Adobe Falls.



Here is a link map to the Adobe Falls area along I-8



Adobe Falls Open Space & SDSU Expansion
It's unfortunate that the majority of youth who visit here have zero respect for the natural beauty of the area. Clearly the area has that exotic attraction factor going for it, but after all the drinking and partying they engage in, they leave it a complete mess and have ruined most of the namesake adobe tan bedrock strata loaded up with graffiti. The photo to the right here is at the top of Adobe Falls just before it takes the plunge down the canyon. I highly doubt that most people are even aware that the palms are all non-native and unnatural to this area. The stream drops sharply and meanders down and around through the valley on it's collision course with the real San Diego River which comes out of Santee, Lakeside and Cuyamaca Mountains to the northeast. But what most don't realize is that every single side canyon on both sides of I-8 is loaded with hundreds of these same large Mexican Fan Palm colonies up and down all the dry washes. Actually the washes are not all that dry any more as they have been utilized by the building industry and city as part of the municipal storm drain infrastructure, Hence the reason for so much extra water which allows palms to thrive. The other reasons for water's permanent presence is basically public wastefulness. Washing cars, watering landscapes, and any number of ways and reasons people use and waste water. Thousands of small curbs and gutters all collectively trickling their cargo together into larger culverts and other flood control channels all meeting upstream and contributing to what was and technically is Alvarado creek. Many references will call this water course north of SDSU as the San Diego River, but Adobe Falls is on Alvarado Creek, not the San Diego River. Alvarado Creek joins the San Diego River at the mouth of that canyon at a district of San Diego called Grantville. They even have a Trolley Station there now. Now let's venture a little further west of Adobe Falls and visit one of the many watershed tributaries along either side of that canyon east of Grantville.


Image: Google Earth

The photograph here is again brought to us from Google Earth. This is about halfway between Waring Road and College Avenue on the south side of Interstate 8 freeway. The bridge you see is fairly new as it is the newer extension of the San Diego Trolley line. So from this east bound shoulder lane looking back up the hillside here of homes just west of SDSU there are a number of tributaries to the main canyons and these were historically almost always dry, except of course now that has all changed with the water run off from public streets above. This is also a north facing slope so evapo-transpiration is going far less than on the south facing slope on the north side of this same canyon which is almost totally lower growing coastal sage scrub. Notice the Mexican Fan Palms. There are actually far more extensive long colonies than the photo here gives credit for. But this is common all the way to the Pacific Ocean on both sides of the greater part of the wide Mission Valley. A simple drive and exploration of canyons and side streets can verify the massive extent to which Mexican Fan Palm has taken over all canyon courses that flow down to Mission Valley. Now lets take a short side trip to the opposite side of Interstate 8 freeway to Waring Road which travels up Navajo Canyon up to Allied Gardens. 


Image: Google Earth

Once again, here's a Google Earth of Waring Road well north of Interstate 8 freeway and just before you drive out of the canyon to the Allied Garden's flat plateau area. The canyon on the left is yet another example of how Mexican Fan Palms have taken advantage of an unnatural circumstances and crowded out the native dry canyon vegetation, but this canyon is no longer dry. It is fed from waste water and storm runoff from the city neighbourhoods above. This has been replicated throughout the entire city and surrounding municipalities. Of course the City's use of the natural geography and dry washes makes sense because these gullies and canyons  efficiently divert flood waters during rainstorm events to keep streets safer and drier. Now I say flood waters because the collectively, all storm water buildup is made by all man the made concrete and asphalt surfaces which eventually come together and causing the flooding. In this Allied Gardens region there are also a number of other plants which have ultimately invaded San Diego's natural riparian corridor of infrastructures and made them a hostile environment to not only native biodiversity, but wildfire hazard to human habitation during these present times of later day mega-wildfires. For example there are three major invaders along with the Mexican Fan Palm, Arundo Cane [Bamboo or sugar cane looking plant], Brazilian Pepper [water loving, unlike the California Pepper which prefers drier circumstances, hence lack of invasive qualities even it will naturalize sporadically] and last but not least the Salt Cedar or Tamarisk [also another major player in not only riparian ruin, but wildfire spread]. The other problem appears to be that in some locations, these fan palms are becoming a storm drain nuisance by hindering flood water movement by impeding it's flow. Here is a photo below where some Fan Palm removal has been taken in Navajo Canyon Open Space.


Image by Eric D. Bier

Navajo Canyon Open Space below Allied Gardens

A slow drive up Waring Road and glancing side to side and you'll just about find them everywhere. Clearly at the top of the plateau where all the 1950s housing tracts are located, people have them in yards everywhere. The Mexican Fan Palm is a heavy producer of seeds and hundreds of seedlings can be found almost anywhere. One of my biggest pet peeves when it comes to plants is the mis-label or mis-identification of trees of the same species and generally [believe it or not] by those who are supposed to be experts. I wrote about this earlier where San Diego Safari Park botanical experts have labeled American Sycamore or London Plane tree as California Sycamore in the Chaparral habitat exhibit. I've seen many Retail Nurseries do the exact same thing. 

So what's the Difference between the two ???
California and Mexican Fan Palm are always incorrectly identified in journals, government reports and science literature. The two couldn't be more different despite some of the obvious similarities in physical appearance. For one the Mexican Fan Palm comes from Mexico, is more slender trucked, eventually getting 70' - 90' or 100' foot tall or more. They are probably the most iconic tall skinny palms seen around Hollywood and other Los Angeles' boulevards, Riverside city streets and orange groves around Redlands, etc. Take a look at the picture to the right. One negative about the fronds and maintenance, unlike the fatter trunk California Fan Palm, the Mexican Fan Palm will shed their fronds in wind storms which creates a dangerous pedestrian or homeowner hazard below. Fire has nothing to to with them falling although they will fall off when on fire and blow far away from the tree creating spot fires well ahead of the main fire front line. The native California holds almost all their fronds throughout life unless they catch fire of course. The leaf frond of the Mexican is also much smaller and brighter green.


The California Fan Palm on the other hand has a much fatter or larger diameter trunk than slender Mexican Fan Palm. The California Fan Palm is also not as high, perhaps to 60 foot. The fronds are a duller olive green and not as bright green as the Mexican Fan Palm. Those fronds are also much much bigger and wider spread than Mexican. The growth of the California Fan Palm is far more slower than the Mexican Fan Palm and this is why they have mostly fallen out of favour with the professional landscaper and their clients who want instant landscape. The reasons you see them in older neighbourhoods of Southern California is because that was the only palm available other than the other icon Canary Island Date Palm, which also naturalizes very well behind the Mexican Fan Palm. There is just no patience anymore for waiting for a tree to actually become a tree. The California Fan Palm also doesn't necessarily naturalize as well as it's Mexican cousin on the western side of the Southern California mountains. not that they can't, but it's not as common. Interestingly, another problem in identification could also come from the fact that both of these Fan Palms will hybridize very easily which I found out in the 1980s-90s was a problem for growers dealing with purebreds in Coachella Valley. 




Call you tell which are California and which is Mexican Fan Palms

Now as a quick example of what I am talking about when it comes to experts who should know better when it comes to plant identification, take a good read of this city of San Diego canyon rehabilitation and maintenance planning report. When you scroll down to page 35, notice the photograph of Rancho Bernardo Canyon and the reference to the trees described as California Fan Palm (Washingtonia filifera) which in reality are clearly Mexican Fan Palms. Not even any mention of the Canary Island Date Palms presence there either. There is simply no excuse for mistakes like this where the city hires expensive experts to do their studies. This is the same irresponsible work that was done by supposed experts  at the San Diego Wild Animal Park's chaparral exhibit. The term California Fan Palm in this instance can be likened to the California Pepper Tree designation. Neither of these trees are natives, but their favoured place in our history of California landscapes is done by humans who as time goes on simply forget the history and consider them as indigenous as they consider themselves. But highly paid experts have no excuses.
http://www.sandiego.gov/planning/programs/mscp/pdf/reports/2013/02_att2b_cyn_sewer_clng_oscac_stat_rpt.pdf
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It wouldn't be right if I neglected to mention another kool Fan Palm native to Baja California
Mexican Blue Fan Palm (Brahea armata)


Image: Google Earth

corner of Vulcan St & Danny St , El Cajon California, USA

I know, the yard doesn't look like much, but it use to before it was sold. For four years I walked back and forth from home to work as head landscaper and passed by this house on the corner of Danny St and Vulcan St in El Cajon California. Sometimes I'd just stop in front to gaze at this amazing blue fan palm. What really made the house and yard was this singular giant Mexican Blue Fan Palm standing all by itself in the lawn, much like the ones in the photograph at the right. The palm frond foliage is a beautiful unique blue green with gray haze. Even when it flowers, it's far more beautiful and impressive than the two palms I have described above. This one also had an amazing large diameter trunk as well, the largest I've ever seen. Apparently not long after this house was sold the new owner took a chainsaw to the Blue Fan Palm and removed all but what looked like a perfectly flat round table which they placed potted plants on top for a while. Eventually that stump decayed and they completely removed it as you can see in the above Google photo where the scar is still evident in the lawn. Aside from the shock one day passing by and seeing it being gone, I realized that as a result of the owner's ignorance, he or she lost out on many 1000s of dollars. Such large trees like this one are worth that kind of money because they are so rare to come by and take so long to grow. In that respect they are much like the large Sego Palms in value. The other draw back to these Palms besides people preferring green palms is that this palm is even slower growing than either of the Mexican or California Fan Palm. But apparently this guy didn't know that. One thing I did learn from the growers in Coachella and Thermal is that the Blue Fan Palm when dug out and hauled to a new location has to have it's roots burned to cauterize the wounds because otherwise the palm even if planted will bleed to death. The other fan and date palms you see hauled around on large flat bed trucks and planted do not have this problem. Speaking of hauling palms and planting whole large ready made trees, here is an amazing house transformation below in the Coachella Valley where older 1970s house was remodeled and yard transformed. Beautiful job and I'll close this post with this picture and link of the story underneath the photograph.




Ashley Hacksaw: "A Tour of our House the exterior"

In Defense of the Mexican Fan Palm (Washingtonia robusta)
While it's true I have targeted the Mexican Fan Palm here as the main subject of this article and referenced it's invasive nature as we have labeled it within this Southern California environment, the plant itself is not to blame. It's people. The palm isn't no more invasive than say the Salt Cedar is. The word invasive comes from another word more commonly used with human beings, "invasion". Take a look at the dictionary definition of this word: 
Invasion: "an act or instance of invading or entering as an enemy, especially by an army. the entrance or advent of anything troublesome or harmful, as disease. entrance as if to take possession or overrun"
Today it his becoming popular and hip to assign description of plants as sentient beings. They are not. While scientists utilize many metaphors and euphemisms in describing some of the incredible behavioural traits and complex sensory mechanisms within plants and their cooperation with each other in all  ecosystems, they do so through their genetic programming and sensory epigenetic mechanisms. They simply grow successfully or unsuccessfully within the environment they find themselves placed. When humans in ignorance change their environment it brings consequences. Rather than admitting error on their part, they tend to blame the plants, animals, birds, insects, etc etc etc by assigning to them negative terminology or labels normally used for people, in that they can now justify to their fellow human being why they should be allowed to pursue yet other irresponsible actions [mostly likely of a deadly stupid chemical or mechanical nature] in eliminating them, which often results in further unforeseen consequences. Mexican Fan Palms, like Canary Island Date Palms or Brazilian Pepper Trees are not scheming planning invaders, their sensor mechanisms are simply responding to the changes provided by people who in this case are merely wasting water. Take the water away and the plants will eventually decline in vigor and propagation of themselves will likely also cease. But homeowners and planners should bear in mind the present catastrophic circumstances of Climate Chance they [worldwide] have collectively created and now understand the newer need of  maintaining their landscapes accordingly. I'll have another post on human mistreatment of the natural world is a reflection on how they have treated each other throughout history. Stay tuned!

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Further Important Reading References
Southern California and Palm Trees 
Important (September 2015)Update for Landscapers who have chosen Mexican Fan Palm over the California Fan Palm because of it's faster growth for instant tree 
California Fan Palm (Washingtonia filifera) growth explosion with Mycorrhizal Fungi 
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LA Times: Gardening Hangovers Part-II - Mexican Fan Palms
Piety and Perversity: The Palms of Los Angeles by Victoria Dailey
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Examples of Fire Hazards 
Palm trees help spread fire in Yorba Linda


FIREFIGHTERS BATTLING VEGETATION FIRE IN SKY VALLEY


MORNING POLL: HOW MANY WILDFIRES WILL BE CAUSED BY CRAPPY FIREWORKS WITHIN FIRST YEAR OF THEIR LEGALIZATION?


Jesusita Fire likely a sign of things to come Wildfires Drought, invasive weeds, warming put much of state at risk, experts say



Check out the video below of why it is so stupid to allow fireworks any time of year to the public. Trust me, palm trees are prime targets for these creeps


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Adobe Falls, San Diego California - SDSU Area
Hidden San Diego: Adobe Falls
 The Daily Aztec: "Trespassers resort to Adobe Falls"
San Diego Reader: "Roam Adobe Creek Falls"
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Navajo Canyon Open Space
Navajo Canyon Open Space Trail Map
San Diego Reader: "Navajo Canyon Open Space"

6 comments:

  1. Interesting read!! Those palms on fire are amazing.

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    1. Thanks. The Mexican Fan Palm is so invasive, even taking over many large river riparian areas like the San Diego River. I can even spot them from Google Earth.

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  2. Very informative, I really appreciate the time you took to describe these popular palms. I live in Los Angeles and I planted a Mexican Blue Fan Palm in the front yard since it is easier to control. I was planning to do a mass planting of Mexican Fan Palms in the back yard, but I do not think I will now. The back yard is an acre of hillside.

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    1. Mexican Blue Fan Palms are beautiful and in my opinion have one of the most brilliant flower frond arrangements and I like the fact is is slower growing and not as tall. However, both the Mexican and California Fan Palm growth can be accelerated by inoculating them heavily with the right mycorrhizal fingi mix. I use one from Mycorrhizal Applications Inc from Grant Pass Oregon called MycoApply Soluable Maxx. Palms are endmycorrhizal, although under certain circumstances they will become ecto-mycorrhizal. Here is a link below of my native palm oasis project in my mum's front yard and the difference inoculation did for them

      California Fan Palm (Washingtonia filifera) growth explosion with Mycorrhizal Fungi

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    2. Thank you, I will look into that fungi mix. I was wondering, do you know if the Mexican blue fan palm hybridizes with the Mexican fan palm? The neighbor has 2 Mexican fan palms and I'd like to keep any seedlings of the blue palm to give away, but only if they are pure. I know the Mexican hybridize with the California palm, and to be honest I'm not a fan of the filibusta hybrid. Also, while the California fan palm has a unique look that I appreciate, I notice that a lot of them tend to look rather sickly or scraggly. I see more dead looking California palms and I've been hesitant to plant any of those for that reason.

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    3. I'm not sure about a blue cross with a Mexican, but yes California Fan Palm (Washingtonia filifera) and Mexican Fan Palm (Washingtonia robusta) easily hydredize well. As far as health goes, they do best in heat compared to the Mexican. I never have boticed the filifera reseeding themselves on the west slopes of the mountain ranges like the Mexican does. Are you in L.A. or other coastal areas ??

      Dave's Garden - Hybrid Palms


      The Mexican Blue Fan Palms are Brahea so I doubt they will ever cross

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