TREES, PLEASE! An Update, a Suggestion and a Request
- 19 hours ago
- 4 min read
By Tim Clancy, for Let’s Talk Plants! September 2026.
An Update, a Suggestion and a Request
Several years ago, in “Diamonds Are Not a Palm’s Best Friend,” (SDHS Newsletter of November 2021) I wrote about California fan palms (Washingtonia filifera) suffering from diamond scale in coastal San Diego County. The palms pictured with that article provided a useful demonstration of what happens when an otherwise excellent plant is grown where environmental conditions favor a chronic disease.
This is an update to that story, a suggestion for the City of Encinitas, and a request concerning some highly visible palms at Cardiff State Beach.
The Update
The California fan palms pictured in the earlier article continued their decline. In December 2025, they were finally removed.
Their removal brings the original story to a predictable and rather unsatisfactory conclusion. These were not inherently bad palms. Washingtonia filifera is California's only native palm and, in its appropriate environment, can develop into a magnificent and extraordinarily durable specimen.
The problem was the location.
Diamond scale, caused by the fungus Phaeochoropsis neowashingtoniae, is particularly associated with California fan palms growing in coastal areas and other locations subject to marine influence. We have seen it in Escondido about 14 miles from the coast. UC Integrated Pest Management describes the characteristic result: older leaves prematurely yellow and die, the crown becomes substantially reduced, and the palm loses vigor.
You Can't Fool Mother Nature.
Anyone of a certain age may remember the Chiffon margarine commercials (viewable on YouTube, search “chiffon and mother nature”) in which Mother Nature discovers that she has mistaken margarine for butter. Her memorable response was:
“It’s not nice to fool Mother Nature.”
Over the years, the expression evolved into an even simpler proposition: You can't fool Mother Nature. There may be no better illustration than the California fan palm growing under coastal influence.
UC Cooperative Extension puts the matter rather plainly: the best control of diamond scale is to avoid planting palms with Washingtonia filifera genetics in coastal landscapes.
That is not an indictment of the California fan palm. It is an application of one of horticulture's oldest principles:
Right plant, right place.
The Suggestion
The City of Encinitas currently has seven California fan palms in its municipal tree inventory, as of July 2026.
Given what is known about diamond scale and coastal influence, I suggest that the City develop a planned program for their eventual (soon) removal and, where appropriate, replacement with species better suited to the Encinitas coastal environment.
This need not mean removing seven palms tomorrow.
Rather, the City should recognize that Washingtonia filifera is a predictably problematic species under our environmental conditions and manage the existing population accordingly. Each palm should be inspected for diamond scale, crown condition, vigor and remaining useful service life. Palms in acceptable condition could remain while they continue to provide reasonable landscape value. Palms in significant or progressive decline could be scheduled for removal and replacement.
Most importantly, additional California fan palms should not be planted where coastal conditions make chronic diamond scale reasonably foreseeable.
This is preventive urban forestry. Once a predictable incompatibility between a species and a planting environment is recognized, continuing to reproduce that incompatibility makes little sense.
The Request
There is also a conspicuous example over which the City of Encinitas apparently has no direct jurisdiction.
At Cardiff State Beach, several California fan palms are in substantial decline. The property is under the jurisdiction of the State of California rather than the City of Encinitas, but the distinction is largely invisible to residents and visitors.
Cardiff State Beach is, after all, in Encinitas.
A visitor driving through Cardiff does not look at a declining palm and think, “That tree is the responsibility of another governmental agency.” It is simply part of the landscape of Cardiff and Encinitas.
For that reason, I suggest that the Encinitas City Arborist write to the appropriate State of California officials, document the condition of the California fan palms at Cardiff State Beach, and request that the State evaluate them for removal and replacement with species more appropriate for the location.
The City would not be telling another agency how to manage its property. It would be doing what cities routinely do when conditions on property controlled by another governmental entity affect the appearance, function or interests of the community.
There is also an opportunity here.
Rather than simply removing declining palms, replacement could demonstrate thoughtful species selection for a Southern California coastal landscape. The objective should not necessarily be to find another palm that looks exactly like Washingtonia filifera. It should be to select plants capable of developing into attractive, sustainable specimens under the conditions that actually exist at Cardiff State Beach.
