Phoenix sylvestris help…

[Looking Glass]

I’ve got a friend that has an issue with what I presume is Phoenix sylvestris at his house.   These palms have been in the ground >1 year, probably more like 2 years.   Planted locally here/10b, in what is likely fast draining, calcerous, sandy local soil.   Likely not fertilized much, if at all, I’d bet.  

Pretty handsome young palms, and these normally do pretty well around here.  Having trouble with yellowing of the old leaves, which seems pretty straight forward.   Magnesium and potassium deficiencies are naturally troublesome here, and Phoenix family palms classically display these here, if not supplemented.  

Looks like the lawn team has overpruned these a bit, exacerbating things, but also eliminating the evidence.   

I’d give the generic advice of fertilizing the drip line with high-end, timed release palm specific fertilizer 4x/year (I like Palm Gain and TreeSaver based on availability).  And fixing likely K/Mg deficiency with 2.5 cups of langbeinite each, scattered every 4-6 weeks, til corrected (probably a year), then 3-4x per year after that.  And stop over-trimming the old fronds even if fugly.  

But I don’t grown any of the Phoenix palms other than roebelenii, so it’s just generic advice.   

Can any of you guys that grow these, offer specific instruction (feeding, irrigation, K/Mg, etc…) for future care that would help these guys blossom into knockout specimens in this environment.  It’s been hot and pretty dry, for the wet season lately.   The good rains have mostly been passing us over along the coast down here.  

Thanks for any input.  As always, inspirational photos are welcome.