What’s wrong with my Bismarckia ?

[Rudy yuma,az]

I have four Bismarck in my yard and one is now looking different than the other three. It is planted in full sun and has be growing good all summer but now all the new growth is yellowing and the fronds are a lot smaller. Is this normal ?

[Xerarch]

Wow, I can't say what's wrong, but that actually looks pretty cool, if it could be healthy like that. 

[Merlyn]

@Rudy yuma,az I'd guess a Magnesium deficiency.  I haven't seen a Bismarckia look like that, but it seems to fit the below symptom list:

• 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 leaves but generally 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

 

[Rudy yuma,az]

What  fertilizer recommend do recommend?

[Rudy yuma,az]

What fertilizer do you recommend?

[Merlyn]

I'd add about a pound of any good "palm special" fertilizer.  Around here the recommendation is PalmGain 8-2-12 or Florikan, but that might not be ideal for AZ soil.  For the apparent magnesium deficiency I'd add some Magnesium Sulfate granular.  I use the Rite-Green brand from HD, about 2 handfuls is reasonable.  Some splotchiness in the fans could also be potassium deficiency.

Some of the fronds are a bit "twisty" compared to normal, and this frond shows *maybe* a transient boron deficiency:

It's not fully necrotic like this one from Broschat, but it follows the same pattern of a transient deficiency when growing:

I'd make sure that your fertilizer contains some boron, since your mulch is lava rock and not decaying pine bark.  Usually palms get enough boron from decaying mulch or other plant matter, but that probably isn't happening in your yard.  So I'd just make sure your fertilizer has the sort of normal 0.02-0.1% amount.

[GeneAZ]

The old growth is not affected.  Since it is showing only on new growth, it is an immobile micronutrient problem which means the problem micronutrients under suspicion are:

Calcium, boron, iron, sulphur, manganese, copper and zinc.

To me, manganese and calcium are the main susupects.  A fert package with all the micros would be my next move.

 

 

[Will]

23 hours ago, Merlyn said:

@Rudy yuma,az I'd guess a Magnesium deficiency.  I haven't seen a Bismarckia look like that, but it seems to fit the below symptom list:

• 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 leaves but generally 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

 

Amazing list! Thanks!

[Merlyn]

@GeneAZyou are right on the Manganese vs Magnesium.  Around here there's a lot of Magnesium deficiencies in Phoenix palms, but it's always on the older fronds yellowing from the tip of the leaflets inwards.  It's never on the newer fronds.  Manganese shows up on the new fronds and gets worse over time.  I think I need to adjust my notes in my spreadsheet so I don't make that mistake again.