Need help finding a specific fertilizer for my Coccothrinax Borhidiana (rare Cuban palm)

[Miami Mark]

Hi, I have 4 of these beautiful palms which are endemic to Cuba and grow on a limestone beach.  They're seriously endangered in the wild so I feel fortunate to have them. One of my palms is struggling.  I'm told its a nutrient problem.  I read that this palm grows best in a Serpentine soil -- rich in nickel and/or heavy metals such as iron, chromium, cobalt, and manganese.  No calcium.  And could use a regular iron/manganese supplement.  My question is this:  Where do I find a fertilizer such as this????  Thank you in advance for your assistance.  PS:  I have attached two photos -- one is a healthy vibrant CB palm, and the other is the unhealthy palm.  They started exactly the same size. 

[SeanK]

Fertilizers with iron are easy enough. I would take two soil samples and bring them to a county extension office for analysis.

[Merlyn]

I'm in the Orlando area, so I don't have any direct experience with growing in the coral sands of the Miami area.  So hopefully some Miami people can chime in.  My recollection is that Florikan is good for Miami, and you may need to supplement as needed with extras.  I use Rite Green Manganese Sulfate and Magnesium Sulfate, and Langbeinite/SulPoMag/K-Mag to add as needed.  Here's my cheat sheet for nutrient deficiency symptoms:

• 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 inwards
• Magnesium -Yellow linear bands on oldest leaves first, transitions to solid green at the base of each leaf. Never causes leaf tip necrosis
• 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.
• Manganese - Lengthwise necrotic streaks in leaves with dead and curled leaf tips. Similar to bands showing Magnesium deficiency
• 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
• 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
• 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

As a guess on your two palms, it looks like the top one might have gotten some sunburn.  Sunburn will show up as reddish/brownish/orangeish streaks in the leaves.  Those then later die off leaving irregular streaks of dead frond, which kinda looks like the photo.  If it's getting more PM sun than the other then that might be one of the bigger issues.  The good news is that if it's sunburn then it'll adapt and the next fronds should grow out okay.

[Miami Mark]

Merlyn, this is INCREDIBLY helpful. I can't thank you enough.