Foxtail Palm Help

[AMFL]

Hello, I have a foxtail palm that grew really well for about two years but has slowed this year and seems to have issues (see photos). The trunk doesn't seem to be getting thicker, the old fronds are turning brown and shriveling, new fronds are drooping lower than the old fronds, and new shoots open early. I use a granular palm fertilizer every 3 months. I'm in Florida and it has rained a lot recently, not sure if that's a factor. Any ideas on what is wrong?

[Merlyn]

@AMFL welcome to PalmTalk!  My first thought was a severe Magnesium deficiency.  The Christmas Palm along the fenceline behind it in the first photo has yellowed tips, a common sign of a mild Magnesium deficiency.  If your Foxtail started out with yellow tips at the end of the oldest fronds, and just kept getting worse, then a good handful of Magnesium Sulfate will help. 

If you are in coastal East FL you may be on soil with a lot of coral shell.  High pH soil makes it difficult for many (but not all) palms to absorb nutrients.  What fertilizer are you using, and are you on coastal seas shell soil?

[Palmerr]

Yeah seems like the other foxtail is doing well if both palms (The small Foxtail and the Christmas Palm) are doing that yeah its something in your soil like a low amount of something which is, Mg deficiency!

Its good its not a disease!

[Harry’s Palms]

I really hate to put this out there but I had one here in Southern California that was in the ground for a total of ten years . It was a bit bigger than yours and it started doing that . All my other palms in that section of my yard looked great but the Wodyetia just went light in color and started producing smaller , weaker fronds. My mentor told me they are not reliable in my area but I kept thinking it was there a long time and looked great. He had me add SuPoMag which I did as prescribed and nothing . It took 3 years to finally die. I always try to save a palm if they get in trouble . Harry

[AMFL]

I'm using Miracle-Gro Shake 'n Feed Palm Plant Food, it has Mg in it but maybe not enough? I have 3 other foxtails in my yard not too far away that are doing great with the same fertilizer. There are some shells but it's mostly normal soil. 

Is there a certain brand of magnesium sulfate you recommend?

[AMFL]

and thank you for the responses!

[Merlyn]

@AMFL i have a big 20lb bag of Magnesium Sulfate granules that I bought from HD, I think.  It is either Sunniland or Rite-Green brand.  I'd do two handfuls sprinkled around the mulched area on that Foxtail, and a handful on the Christmas Palm in the background.  

Hopefully it's just a deficiency and not some disease like Ganoderma or Thielaviopsis.  The yellowed parts won't ever go back to green, but hopefully it stops where it is!

[Christopher Dillman]

13 hours ago, Merlyn said:

@AMFL i have a big 20lb bag of Magnesium Sulfate granules that I bought from HD, I think.  It is either Sunniland or Rite-Green brand.  I'd do two handfuls sprinkled around the mulched area on that Foxtail, and a handful on the Christmas Palm in the background.  

Oh, epsom salt right? Here I am searching for MS at retailers here in San Diego and coming up empty.

Got the same issue with my two queens here. Good news is new green fronds are popping in after four years (worth the wait 😆), then I'm pruning the brown fronds over time.

I only did one hit of epsom salts back in Mar (+ Happy Frog soil conditioner w bat guano), one or two back in 2022 and 23, but thinking it needs to be an epsom party three times a year.

[Merlyn]

@Christopher Dillman I've just used the Magnesium Sulfate because a 20lb bag of granular was about $15.  I bought it years ago and use it mostly on my Phoenix.  I started adding some to the Beccariophoenix Alfredii in December, because they were coming out of winter looking great...except for some yellow tips on older fronds.

In the detail photo on the Queen I see some translucent yellow dots.  That could be the "spider mites" that the tree guys mentioned, or it could be a mild potassium deficiency.  This is my "cheat sheet" for deficiencies.  You can see the sometimes splotchy and frizzled ends on old fronds.  I'd consider adding some Sulpomag/Kmag/Langbeinite as a long-term solution. 

• Nitrogen - Older fronds turn light green uniformly, new fronds remain dark green until deficiency is really severe
• Potassium - Older fronds get translucent yellow/orange or dead spots on leaves, especially at the tips. Caryota and Arenga get random splotched dead spots in leaves. Sometimes tips are curled or frizzled. Always starts at tips of oldest leaves, moving upwards
• Magnesium -Yellow ends on oldest leaves first, transitions to solid green at the base of each leaf. Does not cause leaf tip necrosis until really severe.
• Iron - Many times caused by overly mucky soil and root rot. Starts with new spear leaves with yellow-green or even white, possibly with spots of green. EDDHA works up to pH of 9, 3-5oz per 100sqft
• Manganese - Lengthwise necrotic streaks in NEW leaves with dead and curled leaf tips. Similar to bands showing Magnesium deficiency. Mn is NOT mobile, so it can't be stolen from old leaves.
• Boron - Bent or necrotic or distorted leaf tips, distorted or bent spear, bands of dead spots on new fans, spears that won't fully open, stunted fronds
• Water - Underwatering brown at the edges first, later followed by yellowing of the whole leaf. Overwatering can be drooping fronds turning yellowish and losing color
• Calcium – New leaves are stunted and necrotic, eventually growing only petiole stubs. Deficiency is rare. High pH from adding calcium can induce Magnesium, Manganese, Iron and Boron deficiencies.
• Dolomitic Lime or Azomite - Magnesium Carbonate – reduces acidity/raises pH – slower release and adds Magnesium, helps avoid Potassium deficiencies in Cuban Copernicias. 5Lb per palm on full-size Copernicias and a bit less on Kentiopsis Oliviformis
• Garden Lime - Calcium Carbonate – fast release but works well. 5Lb per palm on full-size Copernicias and a bit less on Kentiopsis Oliviformis
• Sulfur - Elemental sulfur powder or prills reduces pH, 1/2 ounce per cubic foot in sandy soils
• Sunburn - Orange/Red/Brown streaks on surfaces facing the point of hottest sun, typically the worst case is around 1-4pm. Sun tolerant species will adapt and grow out of it. Shade loving species may never adapt.

[Merlyn]

@AMFL there are two different MG palm fertilizers.  One is 8-4-8 and the other is 8-2-12.  The general recommendation here is PalmGain or Florikan 8-2-12 at a rate of 1.5lb per 100sqft of canopy, 4x per year.  For a ~10 foot diameter crown that's 5 * 5 * 3.14 = 78sqft, so 1.5lb * 78 / 100 = 1.2lb of fertilizer per palm 4x per year.  That's a good ballpark.

As with Christopher's palm, the older fronds have frizzled ends.  I didn't notice that earlier.  So it might be a combination deficiency of Magnesium and Potassium.  Sulpomag/Kmag/Langbeinite may be a good choice to add to that one, or just add a bunch more of the regular fertilizer.  If you have a lot of rain runoff in that area, it might be washing away the fertilizer pretty quick too.