Washingtonia Filifera browning

[Warner]

I have three well established native fan palms,  each about 15 feet tall, all on the same drip irrigation.   All three had their lower to mid fronds turn from green to  yellow then brown within a matter of days.  The upper fronds look healthy and there’s plenty of new vibrant growth though I’m watching for new dying fronds.  The temps went from the high 70’s to the low 90’s in a short period.  It doesn’t look like sunburn as all the mid section fronds turned brown regardless how much sun they get.  Any ideas?  They’ve managed just fine for several years,  I’ve been giving them supplemental water since the browning occurred.  

[Jim in Los Altos]

It looks very characteristic to Lethal Bronzing disease but I’m not sure Washingtonia are susceptible. I’ve seen a number of Phoenix genus and a few other types of palms dying from this incurable ailment. 

[jwitt]

My filifera do the same thing right before new growth resumes in early spring. Like the plant sucks the nutrients out of the older leaves, and partial cold damage.  I do not water during winter and do not resume until I see growth resume,  so I assume my plants browning is partially due to my induced winter drought.

That said, my climate is much colder than yours. 

Could it be a response to a change(lack) of water? My hunch. 

I think your increasing water is the proper response.

[sonoranfans]

Never saw that happen in arizona, these palms are desert adapted.  They do get root rot in winter if roots are too wet according to Univ Arizona AG department.  Might be you had an unusually wet winter and some roots underwent dieback.  If that is the case that its been a very wet winter, supplemental water doesnt make much sense.  At 90 degrees in full sun those palms should not be stressed at all, Ive seen them take a month of 107 to 112F days and not flinch.  When it gets hot water use should increase but in winter there should be less frequent and no irrigation water if it rains within a week or so.  If root dieback has occurred they will drop leaves faster that a healthy palm will.

[jwitt]

Some native groves in California are basically swamps.  The world's lowest temperature surviving filifera(back to back nights of -11f) sit in a water table of less than 5ft.  I do not think it is from a wet winter. 

 

[Silas_Sancona]

( Nervously ) side with @Jim in Los Altos on his thoughts on this.. 

There's a filifera / filifera cross in the neighborhood that has been exhibiting a similar look over the last several months.  Compare it to some others in a yard closer to the house that were cleaned up / trimmed ...don't ask me why.. in ...early January, right as the coldest part of this winter set in.

They laughed at the cold / new fronds that were pushing out thru the cooler weeks this year ..look perfect  ..While the odd one out looks a bit sad..  ( I'll add pictures of the differences between this weekend )


Regarding water ..potential for wet winter - related issues,  several filifera specimens in the neighborhood sit in yards that get absolutely no water, at all, all year..   Fat and happy as clams in a plankton bloom.. extra auga this and last winter certainly isn't going to bother them one bit..

There are a couple others that are planted next to an apartment complex a couple blocks up from the house that sit in the middle of one of the complexes lawn areas and get wayyy more water than i'd provide ..all year.  Complex irrigates their lawn areas at least weekly, even right after some of the good rain events during the past 2 wetter than typical winters here.   Fat and really happy.  Taller perhaps than the ones in the un irrigated yards, ..but that's about the only differences i see between them.  %' age of healthy canopy is about equal.

This circles back to the thought Jim has proposed, that something else might be occurring.  Nervously = the possibility of a disease issue like L.B.

Yea, totally possible they're yanking all their nutrients from the older fronds in preparation for a big, new flush of healthy growth too  ...which is why i'd also suggest keeping a close eye on them.  Hopefully the issue is nothing and will pass quickly once new growth kicks in. Hot enough now that they should really start cranking..

..But, you always have to be mindful of the other, much less pleasant possibility as well.  Just in case. 

[sonoranfans]

14 hours ago, jwitt said:

Some native groves in California are basically swamps.  The world's lowest temperature surviving filifera(back to back nights of -11f) sit in a water table of less than 5ft.  I do not think it is from a wet winter. 

 

https://apps.cals.arizona.edu/arboretum/taxon.aspx?id=293

Cultivation Notes: W. filifera is well adapted to desert climates. Very little water is required, using only once a month and sometimes not at all if rainfall is sufficient. The California fan palm is best grown in open spaces, with full sun exposure and well drained loamy or sandy soils. Soil that is too moist can make to root susceptible to root rot. This tree is a hardy plant, with temperatures below 18^oF should be avoided (1,3). 

 

Filiferas are magnificent in AZ with low water requirements, they look like crap in florida and better in inland CA than near the coast due to their preference for desert weather, dry and hot.  I was in AZ for 11 years, CA for 7, they grow great both places but in the drier inland in the heat.    In clay soils they have a bad reputation in AZ for root rot when over irrigated in winter.  Just pointing out that SoCal was hammered the last couple years, from a 15 year drought to releasing water from reservoirs. 

[jwitt]

I hope it is not a disease. The OP is in the native range 

That said, the OP is in an area that is extremely dry and his thought was to give supplemental water.  If root rot, I do not think the newer growth would be unaffected.  

The pics look like mine (almost to a "T" coming out of a induced winter drought.  Fast browning of older leaves, while new growth is unaffected.  

This species has only been in cultivation for a little over a century.  Some things are not understood or misinterpreted. 

I hope it is not disease. 

If they grew on natural precipitation, they would be all over the low desert, like creosote or mesquite. 

Here are two pics in a native Grove.  Given the OP's location, I doubt root rot. I hope it is not a disease. 

[ahosey01]

I respectfully disagree with my fellow PTers here.  I have seen this on Washingtonia before in two scenarios - one, I had a clogged dripper line and the water wasn't being delivered when the heat went up.  Two - I had a pocket gopher that ate a bunch of roots.

You could have either of those problems.  I have a very difficult time believing the treehopper that spreads the LB phytoplasm can survive in this species' native range, excepting perhaps the lushest of oases.

[Silas_Sancona]

11 minutes ago, ahosey01 said:

I respectfully disagree with my fellow PTers here.  I have seen this on Washingtonia before in two scenarios - one, I had a clogged dripper line and the water wasn't being delivered when the heat went up.  Two - I had a pocket gopher that ate a bunch of roots.

You could have either of those problems.  I have a very difficult time believing the treehopper that spreads the LB phytoplasm can survive in this species' native range, excepting perhaps the lushest of oases.

If our annoying Pocket Gophers were a big issue for these, they'd be wiped out / greatly reduced in coverage in my neighborhood ..and in every park full of Washintonia  -of every size,  region- wide  ...AKA: Papago Park, Agua Caliente in Tucson ..all the springs in the desert in CA, N.V., and Utah, let alone in every local/ regional botanical garden's palm collection(s)  which are full of Gophers, Ground/Rock and Antelope Squirrels that would dig up ..and/or consume seedlings/ roots of seedlings / younger specimens, and/or consume ...or greatly undermine the roots of larger specimens when digging their burrows / tunnel systems

Agua Caliente ..Darn Gophers..   Note the partially submerged trunk in the last shot.
 










 Tree hoppers ( and pretty much every other living organism alive ) can ( and do ) survive pretty much anywhere  the climate for each species / group of species is acceptable enough, ...or shifts toward acceptable enough  for them to expand into, settle in, and start cranking out kiddos, who will produce more later  ...inc where CA. Fans grow.  ....That includes the one ..or more... leaf / tree hopper / plant sap consuming insect species that have the potential of transmitting the L.B. pathogen  ...or other diseases that can effect palms / other plants.     Proven science.   Not a " theory ".

[SM458]

I hope you fix your solution. They are gorgeous! 

[ahosey01]

2 hours ago, Silas_Sancona said:

If our annoying Pocket Gophers were a big issue for these, they'd be wiped out / greatly reduced in coverage in my neighborhood ..and in every park full of Washintonia  -of every size,  region- wide  ...AKA: Papago Park, Agua Caliente in Tucson ..all the springs in the desert in CA, N.V., and Utah, let alone in every local/ regional botanical garden's palm collection(s)  which are full of Gophers, Ground/Rock and Antelope Squirrels that would dig up ..and/or consume seedlings/ roots of seedlings / younger specimens, and/or consume ...or greatly undermine the roots of larger specimens when digging their burrows / tunnel systems

Agua Caliente ..Darn Gophers..   Note the partially submerged trunk in the last shot.
 










 Tree hoppers ( and pretty much every other living organism alive ) can ( and do ) survive pretty much anywhere  the climate for each species / group of species is acceptable enough, ...or shifts toward acceptable enough  for them to expand into, settle in, and start cranking out kiddos, who will produce more later  ...inc where CA. Fans grow.  ....That includes the one ..or more... leaf / tree hopper / plant sap consuming insect species that have the potential of transmitting the L.B. pathogen  ...or other diseases that can effect palms / other plants.     Proven science.   Not a " theory ".

To my knowledge LB has not been positively identified in the coachella valley.

Also, I'm only speaking from experience.  I had a Washingtonia filifera with about four feet of trunk.  The follow events happened in order:

- Gopher mounds popped up around the base in early spring

- Temperature rose

- Lower fronds died back

- I killed the gopher

- Temperature kept rising

- Fronds stopped dying

- Palm looks great now

[Silas_Sancona]

3 minutes ago, ahosey01 said:

To my knowledge LB has not been positively identified in the coachella valley.

Also, I'm only speaking from experience.  I had a Washingtonia filifera with about four feet of trunk.  The follow events happened in order:

- Gopher mounds popped up around the base in early spring

- Temperature rose

- Lower fronds died back

- I killed the gopher

- Temperature kept rising

- Fronds stopped dying

- Palm looks great now

Not   ...yet...  

Could already be circulating out here but since no one is busy actively looking for Haplaxius crudus  in the west,  or N. / Western Mexico, ..let alone studying the other Haplaxius  species that already occur out here to see if any of them are capable of carrying the pathogen, let alone transmitting it when they feed ( ..as far as i'm aware, )   We have no clue what is actually happening..  Much like what was occurring with Citrus Greening before HLB / Greening turned up in CA..

While the observation is older ..from 2020,  H. crudus  has been sighted / positively Id-ed in Monterrey, Mex. 

While that side of Mexico does see more rainfall than this side, overall climate is similar. Don't see those weird, one off hyper cold winters on this side of the continent, which would kill off ..or greatly knock back the presence of any spreaders..  I have little doubt that if actively searched for, H. crudis  is probably lurking not too far away from both AZ and CA ...if it isn't already present in one or both states. 


Aside from that,  The other thing that could / could have already introduced both the leaf hopper and the L.B. pathogen to the west ..much faster,  are any palm  grower(s) in the west who is ..or has.. brought in susceptible palm specimens from either TX or FL that are already infected,  which thus introduces the pathogen to the native Haplaxius sps, which may be just as capable of harbouring /  spreading it.  A scenario that is perhaps less likely due to watchful eyes but, coming back to Citrus Greening, have heard stories of inspectors who turned a blind eye to some folks who were moving citrus from FL. to AZ.  ...that turned out to be infected.

South American species in the Genus Triatoma  may be more capable of spreading Chagas disease but guess what.. there are at least? 2 .. species in the genus that are quite capable of carrying / spreading it outside South America.  a couple occur in the South, and here in the Southwestern U.S / CA.

Simply put, if one species has the capacity, it's relatives may also possess it, though perhaps to a lesser degree. 

New and Old World Screw Worm flies are the only two insects i can think of off the top of my head where one species in either genus is capable of behavior the rest of the species in the same genus aren't.

No doubt there are more examples like either case though.