I've got to go out and diagnose some sad foxtail palms today in a beach side property south of Perth, in Port Kennedy. The soils there are beach sand with the odd lump of limestone and pH's ranging from 8-10. How tolerant of high pH are foxtails. This guy has a row of 4 and by the sounds of it is doing everything correctly, but one is stunted and pencilling down while the ones next to it appear fine according to him. My soils are 6.5pH so I can't take any info from my own experience. What do you guys reckon, especially those on limey sand in South Florida. Is high pH and issue with Foxtails?

Best regards

Tyrone

I've got to go out and diagnose some sad foxtail palms today in a beach side property south of Perth, in Port Kennedy. The soils there are beach sand with the odd lump of limestone and pH's ranging from 8-10. How tolerant of high pH are foxtails. This guy has a row of 4 and by the sounds of it is doing everything correctly, but one is stunted and pencilling down while the ones next to it appear fine according to him. My soils are 6.5pH so I can't take any info from my own experience. What do you guys reckon, especially those on limey sand in South Florida. Is high pH and issue with Foxtails?

Best regards

Tyrone

What kind of soil do they grow in native north Queensland? PASCOA says that grow on gravel hillsides. Sound like a high pH to me but maybe someone has further info. There are several around here in soils that are fairly high in acidity.

The area where the foxtails grow north of Cooktown in North Queensland (Near Cape Melville) is a granite rocky area with low growing shrubs etc. Here they have full coastal exposure etc, so salt spray wouldn't be a problem for this species. Soil pH I would imagine would be near neutral. It's not a rainforest area, where constant rotting vegetation would drop the pH into the acid region. However they get lots of rain up there, and that can leach away any calcium carbonate over time. I'm hazarding a guess that the soils in habitat would be neutral to slightly acidic. That doesn't really help my question though regarding very high pH and foxtails.

The area I'm seeing these palms sits on a limestone ridge which has formed the coastline and many of the islands off the coast.

Best regards

Tyrone

My bore is dolomite bore, so I suspect we have a lot of lime in the area... My foxtail don't seem to suffer though...

Regards, Ari

I went and checked it out today. Soil pH was a consistent 8.5-9.0 possibly more. The water pH was also alkaline but my gauge doesn't go higher than 7.6 pH and it was bluer than that highest setting, so I think water pH is up around 8.5-9.0 as well.

The problems are not just with the foxtails. Almost all the roebelinii's have pulled spears now even though the older leaves look fine. Some of the foxtails look fine but some are dying. The Ravenea rivularis looks tormented. They've had a triple A alexandrae just melt away and die. The Howea's are coming out with dead new spears. The D decaryi's look fine from a distance, but they are yellowing a bit and have necrotic leaflets on the newest leaves which are coming away from the rachis due to a black shrivelled area. The Butia's are fine. Cycas revoluta's have scorched new leaves.

Here are some pics. What are peoples thoughts on these.

This is one of the healthy ones.

Best regards

Tyrone

Another healthy one

And a very sad one

A Phoenix roebellini in trouble.

A Howea in the same garden bed as the roebellini's showing the same issue. Necrotic new spear that looks like it will pull out.

All of these palms were reportedly looking fine 6 to 12 months ago. They were all planted about 4 years ago into worm castings and peat.

Any ideas what might be going on here.

Best regards

Tyrone

I have many Wodyetias in my beach garden and they cannot handle full beach exposure.They are in the second and third tier. I find they need monthly applications of fertilser with minor elements.

These are most mature Wodyetias on the left side of the photo.They were planted 7 years ago.

Thanks Scott. It's interesting that you mention regular fert applications with minor elements. What is your soil pH?

Best regards

Tyrone

Anyone is sandy Florida want to comment on what they do in these circumstances??

Best regards

Tyrone

Thanks Scott. It's interesting that you mention regular fert applications with minor elements. What is your soil pH?

Best regards

Tyrone

Tyrone,i really dont have soil.It is almost pure sand.I do start all my palms with soil,peat and rice hulls to get them established and then monthly applications of fertilser with minors.I have had them produce a few stunted or very elongated fronds.I also have this problem with Ptychosperma elegans.My pH is Alkaline.

Thanks Scott for your info.

The palms in this garden are really quite damaged. I believe there are secondary fungal infections eating all the dead tissues created by the micro element deficiencies.

I'm thinking of treating the soil with 50g/m2 of fine sulfur, dug in, adding Magnesium sulfate, and Iron sulfate as quick pH reducers that also release some vital trace elements. I'll also dress with some Micromax from Scotts which has all the trace elements too in ionic form. Then I'll get them to water it all in like mad for two weeks and check the pH at the end. I'm looking at using peroxide on the pulled spear palms, and using Banrot as a soil drench to start knocking the fungus on the head. Of course all dead leaves etc will be cut and disposed of. In the end I think I'll suggest a sheep manure mulch over the whole garden to add some organic matter and improve the nutrient holding ability of the soil as well as get some beneficial bacteria forming in the pH adjusted soil. Hopefully these beneficial bacteria will keep harmful fungi in check.

I think this garden (like yours Scott) will need constant attention to sulfur and micro elements. If I can get the garden back on track, and can point the owners back on course they will follow up with regular trace elements as they've invested thousands on there garden and they don't want to lose it all.

Thanks for your comments Scott. It gives me confidence that I'm on the right track.

Best regards

Tyrone

Thanks Scott for your info.

The palms in this garden are really quite damaged. I believe there are secondary fungal infections eating all the dead tissues created by the micro element deficiencies.

I'm thinking of treating the soil with 50g/m2 of fine sulfur, dug in, adding Magnesium sulfate, and Iron sulfate as quick pH reducers that also release some vital trace elements. I'll also dress with some Micromax from Scotts which has all the trace elements too in ionic form. Then I'll get them to water it all in like mad for two weeks and check the pH at the end. I'm looking at using peroxide on the pulled spear palms, and using Banrot as a soil drench to start knocking the fungus on the head. Of course all dead leaves etc will be cut and disposed of. In the end I think I'll suggest a sheep manure mulch over the whole garden to add some organic matter and improve the nutrient holding ability of the soil as well as get some beneficial bacteria forming in the pH adjusted soil. Hopefully these beneficial bacteria will keep harmful fungi in check.

I think this garden (like yours Scott) will need constant attention to sulfur and micro elements. If I can get the garden back on track, and can point the owners back on course they will follow up with regular trace elements as they've invested thousands on there garden and they don't want to lose it all.

Thanks for your comments Scott. It gives me confidence that I'm on the right track.

Best regards

Tyrone

Good luck Tyrone,your plan is certainly a practical no nonsense approach.

Hi Tyrone,

I think it is not possible to lower pH whenever free lime is present. I took this from

"Alkaline Soils and the buffering affect of Calicum Carbonate"

Curtis E. Swift, Ph.D.

Colorado State University

Extension

Tri River Area Agent (Horticulture)

The Buffering Effect of Calcium Carbonate

The soils of Western Colorado are highly buffered with free lime (calcium carbonate - CaCO3). Any sulfuric acid coming into contact with calcium carbonate will react producing water (H2O), carbon dioxide (CO2) and calcium sulfate (CaSO4). No increase in hydrogen ion concentration occurs in this reaction, consequently no change in soil pH can occur. Instead, an increase in the salt level takes place due to the resulting increase in concentration of the salt gypsum (calcium sulfate - CaSO4).

Tomas

Yes, I've read that sort of info too. The actual cutoff point is a pH of 8.4 Above that free lime exists in percentages (eg 1-5%) I'm hoping this garden is borderline enough to start changing at least the top layer of soil into a more acceptable range. Lime does buffer the soil very much. Luckily it's a sandy soil which has a very low buffering capacity due to a low cation exchange capacity. I read that it takes 600g of Sulfur per cubic metre to drop the pH from 8.4 to 7.4 when Calcium carbonate is 1%, but nearly 3kg of Sulfur per cubic metre if it's 5% Calcium carbonate. Basically if a palm is sitting on a bolder of limestone the entire bolder has to be dissolved before the pH drops. If the palm can't handle the soil above being amended I think it's had it.

I'll see how I go with this case. It's going to be interesting.

Best regards

Tyrone

Tyrone,

I wonder if you (or the owner)could try trenching around the outside of the rootball with a small excavator and backfilling with compost, manure, fertilized topsoil, etc. to provide a short term feeding trough for the palm while you work on the ph long term.

It might provide enough of a boost to get the plant moving again at least. You could probably do every palm in the yard in a day if you had the bulk materials on site and have a skilled operator on the machine. Rubber tracks create very little site disturbance.

I think I read somewhere about a similar technique used in rubber plantations in Malaysia.

Probably a bit extreme....but just a thought.

Cheers,

Jonathan

Tyrone,

I wonder if you (or the owner)could try trenching around the outside of the rootball with a small excavator and backfilling with compost, manure, fertilized topsoil, etc. to provide a short term feeding trough for the palm while you work on the ph long term.

It might provide enough of a boost to get the plant moving again at least. You could probably do every palm in the yard in a day if you had the bulk materials on site and have a skilled operator on the machine. Rubber tracks create very little site disturbance.

I think I read somewhere about a similar technique used in rubber plantations in Malaysia.

Probably a bit extreme....but just a thought.

Cheers,

Jonathan

Actually it was bamboo plantations in China, now that I think about it!

Heavy layer of peat moss worked into the soil as much as possible, and coffee grounds, covered by as acidy mulch as you can find? And micros.

Just kind of thinking out of the box here but all those problems all of a sudden make me think pH is not the real problem. If micro nutrient pick up was slow then you would see deficiencies (like the one sick foxtil) but not sprear leaves dieing all over the place, especially in robes. Phoenix with micro problems look sick all over, your pictures seem to show good foliage. No? The howea too right?

So what else could it be?

We see foxtails here (South Florida) in pure lime rock that do great with regular fertilizer. They look very bad and die without it.Phoenix do well except for problems like LY, bud rot and other fungal problems which may be caused by too much rain in the summer. Howea seem to do best under oak trees as if they like the shade and leaf litter. Changing pH may not be possible except for in the very most top layer where roots can "see" a chance to get some micros. Thats probably why top dressing with mulches (or other substances) works. The root tips that are growing up into the mulch as seeing the micros free of the calciums influence. If you have a lot of insects the root tips will get eaten. Thats why insecticides help when applied to the soil. Also as the mulch breaks down bacteria will suck up nutrients robbing the palm so constant fertilizer is good if this is the battle you are fighting. Thats when it's good to fert more often with less. Some palms will realy shoot up with this approach. Ravenia rivularis is one of them. Don't let them dry out when applying lots of fertilizer as they may burn easier and in the case of the ones that want to get going they need the water anyway.

Man I went on and on. Hope some of this is usefull.

Thanks Ken and Jonathan and others. Ken you are right about some of the robes. They seem to have hit a problem very recently. Fungi are opportunists. They see a stressed plant and find a way in. If a really stressed plant has become a breeding ground for fungi, then eventually this extra population of fungi are going to start invading plants that aren't as bad as the first one infected. Eventually the whole garden bed will be infected and fungal infections spiral out of control. I think this garden is almost at the point of no return if urgent action isn't taken now. I've got to knock the fungus on the head first, then try to reintroduce micros, and then gently lower the pH. Not easy really. I think the Howea's and robes would have remained fine if the dying foxtail wasn't within 20ft of them.

Anyway today I bought 25kg of iron sulfate, 200ml of peroxide for the spear pullers, and 907g of Banrot for a shockingly expensive $240AUD. I will apply some Magnesium sulfate and Scotts Micromax to give some nutrients back.

Jonathan there is no room for an excavator, but in the end this garden needs heavy composts and manures to build up the top layer of soil so the plants can use it. Beneficial bacteria need to be reintroduced as well to keep the brakes on bad microorganisms taking over.

Also I thought about the peat idea, but one cubic metre of peat is equivalent to 600g of sulfur. If you have solid limestone you need to add 4 times the amount of peat than soil. This shear volume gets ridiculous in the end.

Best regards

Tyrone

Foxtails do better in a sandy soil then a mucky one. Here there are places where the soil is black and water retaining and foxtails hate it. The more sandy locations do quite well if you fertilize them regularly.

I went and treated the garden on Thursday. I used Iron sulfate as the first part of a pH reducer. I put the Micromax down to add trace elements. I used peroxide on the spear pulls which made the crowns fizz away like a can of coke, then I used Banrot on everything. Here is a dead trunk of an A alexandrae which rotted away. What can you see there?

Best regards

Tyrone

Anyone know what the last picture is? What can you see there when you look really closely?

OK. No one can see it. It's Pink Rot.

If you see this, get it out of your garden. A stump with pink spores all over it is a ticking time bomb.

This stump is gone now. If you get the same thing in your garden either throw it in the bin in a sealed container, or burn it.

Best regards

Tyrone

Thanks Tyrone - good advice, as ever.

Cheers,

Jonathan

It was good to see Ken Johnson's reply. Most of Miami is on limestone without much soil, so it's not the easiest place to grow things, and there's a whole body of techniques for growing great gardens.

I was at Florida International University's south campus in Miami this week. The meeting room had nice potted Ravenea and there were plenty of palms outdoors. I'm starting to realize that R. rivularis thrives in Florida, if you give it a moist spot. Locally, there's a thriving one almost in the mangroves.