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Help with new Mules - time to worry?

Cool Mule

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These mule palms were planted back in June and seemed to be getting well established until recently.  All of them had some yellowing and frond damage at install (cracks near the trunk where it looked like they were tied up too tight). They each lost several fronds that yellowed before turning brown within the first month.  Recently, the palm on the end has shown more yellowing than the others and the center spear appears to have some yellowing as well. 


All three have shown new growth and the two on the ends have had two spathes emerge.  The palm with the most yellowing had an inflorescence bloom which I cut off a few days later. 


Each palm has a dedicated bubbler that runs on an irrigation zone for 30 minutes and delivers about 30 - 40 gallons of water, several times a week unless we've gotten rain.  The soil is moist but not wet. 


I fertilized a month ago with Sunniland 8-0-10 spread under the mulch in a 5-6 foot radius. I applied about 5 lbs per tree. 


Is the yellowing a major concern? Is this characteristic of overwatering? Underwatering? Too much fertilizer too soon? Still in the transplant shock phase? The yellowing on the new spear has me most concerned.


Thanks in advance for your help!



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Never been to Florida, but I heard it is hot like Texas if so I suspect that the yellowing is transplant shock from being transplanted in the summer instead of early spring. I put 2 palms in ground during summer and it was considerably more difficult to keep them from yellowing vs. the palms of the same species that I planted earlier in the spring.

But I am no expert just a new guy here and that is just my $.02.

That central spear yellowing is not a good sign though, the older leaves is normal but that central spear yellowing is troubling.

Edit: I just re-read your post I have ZERO experience with Sunnyland but 5 lbs of fertilizer seems like an awful lot for a Palm that size. Is that what the directions call for? 

I use a mild organic fertilizer (Palm Tone) which has a much lower NPK and I use very small quantities and it works wonders.

What does the label say about application directions for a tree that size?

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Is this what you used?

If so you do know that it is not formulated for Palms trees specifically right? I am thinking that you might have over fertilizered them possibly. 

Also, Palms only need 3 feedings per year and they need slow release fertilizers that contain a little bit of Phosphorus. (The middle number should NOT be a ZERO.)


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6 hours ago, Dwarf Fan said:

Is this what you used?

If so you do know that it is not formulated for Palms trees specifically right? I am thinking that you might have over fertilizered them possibly. 

Also, Palms only need 3 feedings per year and they need slow release fertilizers that contain a little bit of Phosphorus. (The middle number should NOT be a ZERO.)


Yes, that's it. That fertilizer seemed to match what UF recommends (8-2-12-4 Mg) for palms most closely.  I applied per the directions @ 0.5 pounds per inch of trunk diameter taken 3 ft up. This matched what I'd found in other research (applying per trunk caliper).  These trees are about a foot in diameter. 


It's also been a pretty hot summer here with some good stretches of no rain.  I thought my watering schedule was pretty good though. If anything, these look a bit overwatered to me since they're yellowing but I really have no clue. 

Edited by Cool Mule
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It may be something as simple as too much water wait for other more experienced Palm growers to chime in as I am still new myself, but either way next time use a Palm specific fertilizer for your next fertilization cycle after winter passes.

I use Palm Tone and it only turns my Palms a deep green and then I get explosive growth, I have heard that Palm Gain is also a very popular non-organic choice here, but either way they BOTH contain a small amount of Phosphorus but Sunniland has ZERO which indicates it is not specifically designed for the needs of Palm Trees. I cannot say with certainty if this has anything to do with your Yellowing spear issue, but it certainly is something that is good to find out going forward for your next fertilization because it can become a problem long term.

Also, who or what is UF?

Palm Tone: 4-1-5


Palm Gain: 8-2-12





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1 hour ago, SeanK said:

Isn't phosphorus needed for root development?

A quick search confirms you are correct it helps with root development, and while some argue that Palms need very little to no Phosphorus, there is other literature that says Palms do need it in their feeding regimen.

OP, I think the UF is using Palm Gain 😉look at their N-P-K ratio:

“The 8N-2P2O5-12K2O+4Mg with micronutrients maintenance fertilizer blend described above should release nutrients for up to three months, and thus a three-month application interval is recommended. The suggested application rate for south Florida landscapes is 1.5 lbs of the 8N-2P2O5-12K2O+4Mg with micronutrients fertilizer (not N) per 100 sq. ft. of palm canopy area, bed area, or landscape area. Field nurseries typically apply twice that amount to maximize growth (Broschat 2015b). For landscapes in central and north Florida, winter applications can be omitted and lower application rates may also be adequate, although field nurseries in those regions will probably benefit from the higher south Florida application rates.”


Palm Gain’s website:

Palm tree fertilizer plays a large part in the overall health of your tropical paradise. Palms, ferns, cycads, ixora, and ornamental plants need ample amounts of nitrogen, potassium, magnesium, iron, sulfur, and other micronutrients to produce lush green growth and vibrant colors. Maintain your deep green foliage with PALMGAIN® 8-2-12. Developed by UF–Institute of Food & Agricultural Sciences (IFAS).


But wait here is yet ANOTHER reason to use a PALM specific fertilizer formula, EVEN IF THE NPK is EXACTLY 8-2-12!!! Anyone that is still using a “GENERAL PURPOSE” Fertilizer on their Palms please read below:👇 

Selecting Good Fertilizers for Palms

Summer is coming soon; roots and palm fronds will grow fast! Are you sure that you are applying the correct palm fertilizers? The latest fertilizer recommendation from University of Florida is 8 – 2 – 12 + 4 Mg at the rate of 1.5 lbs. of fertilizer per 100 sq. ft. of palm canopy area. Lately, various fertilizers with the same formulation have appeared in the marked. Which one is the best? Based on Dr. Broschat and Dr. Elliott explanation (UF palm expert specialists and retired professors) a brief justification of why some are good or bad are provided:

Fertilizer Labels A : Is a good fertilizers to use for palms, as they include 100% control-release sources of N, K and Mg. All of the K is present as polymer coated sulfate of potash. All of the Mg is present as magnesium sulfate in the form of kieserite.

Fertilizer Label B: This fertilizer is not acceptable to use for palms because not all of the K is control-release and none of the Mg is control-release. They have included “sulfate of potash-magnesia”, which is 100% water-soluble. So, when the landscape is irrigated or when we do receive our first good summer rain, the Mg will quickly leach and about half of the K will also quickly leach, creating an imbalance in availability of K to Mg and in N to K. This will lead to an increase in both K and Mg deficiencies. The other problem with this fertilizer is that it contains iron oxide and manganese oxides, which are not good sources of Fe and Mn in neutral or alkaline soils

Fertilizer Label 😄This fertilizer is really bad! The only control-release nutrient is the N, as polymer coated urea. The K and Mg are all 100% water-soluble sources, which are highly leachable. The other problem is the micronutrients (except boron) are sucrates, which are nothing more than oxides with molasses – i.e., they are not good sources of micronutrients. This fertilizer should not be used on palms!




Fertilizer A.- Good source of nutrients


Fertilizer B. Not Good for Palms under South Florida soil conditions

Fertilizer C. Not good for palms. All the K is quick release plus contains sucrate


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Could be overwatering and overfertilization, and especially it might be  still in transplant shock so I'd keep an eye on them.

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I thought that a 2-1-3 ratio was optimal. With new plants sans roots, I would focus on root development. Root stimulator and phosphorus.

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  • 3 weeks later...

Update on these palms: older fronds certainly have some yellowing and some have turned brown on the edges following the yellowing. 


The yellow spear I thought I saw appears to have been an optical illusion. Its grown out a bit more and is dark green. 


All palms are currently producing spathes which should open very soon. I'll likely leave these attached.


So, looks like I probably gave them a bit too much fertilizer but only the oldest growth seems to be affected. I've also cut back on their water since the soil seems consistently moist, a handful will stay clumped together when squeezed. We'll see how much more growth they get before winter.

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