Satsuki leaf colour

[NeedlesAndLeaves]

Hi,

Last winter I bought this Kokuko No Tsuki. It is actually growing vigorously. Flowering red. This was my first azalea and I am not so familiair with the species, but I was wondering if the reddish/purpely/brownish leaftips are normal? Or does this mean something else?

Repotted last spring in Kanuma. Azalea fertilizer.
Sun: 8-10 hrs a day (in summer). Watering accordingly (I think)

Tnx in advance!

Grz

 

[Tahoebonsai]

Azaleas are water snobs and most leaf deformations or color issues are usually a ph imbalance, you can get a cheap digital ph meter and some lemon juice or distilled vinegar and get the ph down to like 4 when you water it and it’ll snap back

 

[Time Wizard]

That looks like the fall color setting in to me. It is typical for azaleas to turn red/purple in the fall. That has nothing to do with the health of the tree and it will turn back to its usual green color in the spring.

 

[Deep Sea Diver]

Hmm…

Normal. Merely old spring leaves getting ready to abciss. They normally will fall off, yet this can cause fungal issues for potted s azaleasetc.

Proper fall work entails, amongst other items, removing all but the 4-6 closest leaves around each bud…the summer leaves… and taking off all the spring leaves on each ‘branch’.

Cheers
DSD sends

 

[Glaucus]

This is not the autumn colour. The red is all at the tips. So I would say sun stress. There will also be a difference between spring and summer leaf colour, though Kokuryu should have red on both. But autumn colour can be variable.
Additionally, this azalea is slightly chlorotic. You can see some pale green veininess in some leaves. So that means that the combination of kanuma, the nature of your tap water, and the fertilizer regime you have used is not right to get consistently good results. I see nutrition issues in half the satsuki I put in kanuma, very roughly.
I am not sure yet what advice to give to people growing satsuki in bonsai pots. I believe one should be able to put them in kanuma and just grow them pain free, not having to worry about nutritional issues. But that does not seem to be the case.
Growing peat may have it's own problems. Especially for larger trrees that should be kept into status quo that are in bonsai pots.

It will be quite easy to figure out if it is autumn colour. If it is, the entire leaf should be red in a few days. Autumn colour progression can move really fast. The temperatures moves up again, so that would slow things down, though.
They can turn red almost overnight if temperatures drop near 0C.

Then the spring leaves will fall off by themselves. So I don't really see the reason to manually remove them.

 

[Deep Sea Diver]

My bad… didn’t get to look past the first image due to other issues. Were all these taken at the same time?

The first image looks generally ok, especially since the tree was given 8-10 hours of sun.

The other three look like an azalea given way too much sun and acting accordingly. Not sure about nutrition. Too much sun often makes a potted tree look nutritionally deficient.

Azaleas like morning sun afternoon shade. Not full sun.

A couple notes.

None of the trees here in kanuma, well over 100, look nutritionally deficient. Azaleas don’t actually need much fertilizer, even in kanuma. In fact one could put a 1/4 - dose osmocote plus on in spring, after flowering and in early fall and call it done and the azaleas should do well. However regular fertilization in small doses and foliar feed will accelerate the growth… which is why we do it.

The pot seems too shallow and is glazed. Look for an appropriately sized Tokaname training pot. They are deeper These pots are made of harder terra cotta and breathe. They are used for development and general growing of azaleas. Glazed pots are generally only used for show, then the tree is slipped out and put back in Tokaname training pots (or boxes sometimes)

Last. The lead load is too high in any event. Would at least remove 1/2 of the inner leaves to allow ventilation and sun to penetrate better.

We’ll be starting fall prep on certain satsuki, (Japanese term = Mesuki ) maybe tomorrow, will post an image when I get a chance.

Cheers
DSD sends

 

[Glaucus]

Kanuma should be good, but I got like 30 whips in Kanuma from Japan. And I also have about a 1000 plants in peat/perlite. And basically none of the ones from Japan in Kanuma did very well under my regime.
Only when I moved them to peat/perlite, they started to do better. Which is why I suspect the tap water of being the culprit. I even put baskets with biogold on top of the pots, to more accurately imitate the Japanese. Now, maybe I did that too late because I already saw symptoms. But if I have a hard time to dial in what the satsuki need, then I am not sure if this is the right way for the general public.
So when I see a plant in 100% kanuma, that was fertilized, and is also in the Netherlands, I begin to wonder how 100% kanuma could be adjusted. Either with RO water and fertigation, acidifying tapwater. Or with a different potting mix.
Ideally, just having tap water and rain and not having to worry about anything else is the most pain free and enjoyable way to grow plants.

This is just a slight deficiency. And it is not nitrogen, but iron, because there are veins. So this suggests to me the kanuma pH got too high because of bicarbonate in the tap water.

Kanuma is so much nicer when repotting and fixing the nebari, though. I can miagine peat/perlite being a real problem when used for bonsai, because you cannot really manage the roots during a repot.
But, I haven't tried. When I repot my satsuki, I just open up the root ball and put it in a larger pot. Which is basic plant growing. Not actual bonsai repotting technique. Kanuma will at least partially fall out of the root ball when repotting.
For bonsai, it would be better to have a challenge managing water quality and nutrition, and being able to repot properly. Than not having to worry about that at all, but not being able to repot and manage a plant as a bonsai tree.

 

[NeedlesAndLeaves]

Thanks all for those detailed comments .
The pictures in the post are from the same moment. The ph of my tapwater is around 6 at the moment. Is that still to high for azalea?
I went back through my pictures and saw that this started after repotting (after flowering).
It was rootbound and not draining in the pot it was in.
Before repotting the soil was pure kanuma as well.

So it has been there for a while. It has been growing strongly after the repot and pruning.
The reason for the larger black pot was simply because I want it to be taller and wider and that was something I had at that moment.

I will add three photo’s. First is before repot (may 15th). Second somewhere after repot (July 5th) and the last one is from yesterday.

Thanks for the tips on the fall thinning.

 

[NeedlesAndLeaves]

Forgot to add the photos

 

[Glaucus]

The tapwater pH is quite low which is good. But what matters is the bicarbonate content aka the hardness. The bicarbonate increases the pH in the root zone. The pH of the water itself doesn't matter that much, as it is flushed away anyway and replaced with rain water often.

Chelated iron treatment will also do the trick. Not sure what you fertilized with, but a fertilizer that has EDTA-Fe2+ complex, or EDDHA-Fe2+ complex may be essential for azaleas in substrate.
Kanuma is the golden standard and everyone recommends it, with many good reasons. Note both the sun scald and the chlorosis are minor. But this does make it look a bit stressed.
Since it was just repotted, it responded well, has good growth with lots of strong buds that end in flower buds, I wouldn't worry too much, But the chlorosis t hing is something to watch for next spring.
As for the sun scald, satsuki can take 100% of the sun in most Dutch summers. Just not the weatwave-rich ones. But it could also warm up the pot too much. You can plant them in the garden with full sun no problem, as long as you water during drought. But in a pot, you do want to shade them on the hottest days. They actually do also quite well in full shade.
I assume this one was not in full shade all summer and this symptom I think I see matches what you think the tree experienced.

 

[Deep Sea Diver]

Thank you for those images. Almost looks like the latter image was taken under artificial light!,,,

Anyways wondering if the tree was in a different media and then put into kanuma without washing the roots clean of the other media.

If that’s correct this would be certainly be the key issue. Vs hardness.

The pH is great for azaleas. Do you know the carbonate level of your water… hardness? Likely it’s not too high with that low a pH

Cheers
DSD sends

 

[NeedlesAndLeaves]

The tapwater pH is quite low which is good. But what matters is the bicarbonate content aka the hardness. The bicarbonate increases the pH in the root zone. The pH of the water itself doesn't matter that much, as it is flushed away anyway and replaced with rain water often.

Chelated iron treatment will also do the trick. Not sure what you fertilized with, but a fertilizer that has EDTA-Fe2+ complex, or EDDHA-Fe2+ complex may be essential for azaleas in substrate.
Kanuma is the golden standard and everyone recommends it, with many good reasons. Note both the sun scald and the chlorosis are minor. But this does make it look a bit stressed.
Since it was just repotted, it responded well, has good growth with lots of strong buds that end in flower buds, I wouldn't worry too much, But the chlorosis t hing is something to watch for next spring.
As for the sun scald, satsuki can take 100% of the sun in most Dutch summers. Just not the weatwave-rich ones. But it could also warm up the pot too much. You can plant them in the garden with full sun no problem, as long as you water during drought. But in a pot, you do want to shade them on the hottest days. They actually do also quite well in full shade.
I assume this one was not in full shade all summer and this symptom I think I see matches what you think the tree experienced.

Tnx for your reply. I ferilized with azalea fertilizer. Picture added. You will probably know it.
The watertest did today I also added as a picture. On the left is the teststrip. Hardness is quit low in my area. SW of the country.

I placed it mostly in full sun I must admit.
Next season I will give it a little less sun.

I will keep an eye on the chlorosis.

 

[NeedlesAndLeaves]

Thank you for those images. Almost looks like the latter image was taken under artificial light!,,,

Anyways wondering if the tree was in a different media and then put into kanuma without washing the roots clean of the other media.

If that’s correct this would be certainly be the key issue. Vs hardness.

The pH is great for azaleas. Do you know the carbonate level of your water… hardness? Likely it’s not too high with that low a pH

Cheers
DSD sends

That is typical Dutch moonlight .
No it was dark out so I made the picture under artificial light in my garage.

Unfortunately I made no pictures during repotting. But I guess you are on to something about not washing out the old soil.
I did not do to much on the roots if I remember correctly.
Will make sure to do this next season.
The hardness on the test shows “very low”

I did not have a digital tester so I used my teststrips which I know are not that accurate. But the coloration is quite clear.

Tnx for thinking along

 

[Glaucus]

You can easily look up your Vitens tap water report. But it seems you have softer water than I have. The fertilizer should be quite good. However, it does not contain the chelated iron. So it could be a flaw for that fertilizer. Of course, it will contain some iron in the organic materials. If you get a houseplant liquid fertilizer from Pokon, it will have chelated iron. And ideally you just add a tiny bit of that to either RO water, rain water, or distilled water. And water your azalea with that.

There are some liquid Pokon fertilizers that have the full range of micronutrients, including chelated iron. With fertilizer, your main goal is to add whatever your plant is deficient of. And in your case, it seems to be iron. Which may be because it is lacking in the substrate. But it may also be because the roots are somehow unable to take it up. Which can be pH-related, but also the roots just being able to do their job. Too wet could also be a reason.

 

[NeedlesAndLeaves]

Oké tnx! I will use this great information in the time to come!

Btw do Satsuki’s normally also get autumn colours as Time Wizard mentions?

 

[NeedlesAndLeaves]

Last. The lead load is too high in any event. Would at least remove 1/2 of the inner leaves to allow ventilation and sun to penetrate better.

We’ll be starting fall prep on certain satsuki, (Japanese term = Mesuki ) maybe tomorrow, will post an image when I get a chance.

Ah I did not know that the thinning out and reducing the number of leaves (“thieves” if I am correct?) around the buds was an autumn job.
Good to know. I read this was a spring job in my Satsuki book by Janine Droste. Or maybe both work?

 

[Deep Sea Diver]

Ah I did not know that the thinning out and reducing the number of leaves (“thieves” if I am correct?) around the buds was an autumn job.
Good to know. I read this was a spring job in my Satsuki book by Janine Droste. Or maybe both work?

Hoping all goes well with this azalea.

it is highly likely having two medias in a pot created your issues. We call this lensing, or the island effect. In this case the inner media, the lens or island, holds onto water better than kanuma, which dries out faster. Folks notice the kanuma needs watering and do so, overwatering the core, which leads to root rot. Root rot can reside in a core for a long time.

It is possible the full sun routine, besides stressing the azalea out, might of helped avoid this issue to start with by creating a higher transpiration load and keeping the roots pulling water out of the core at a quick rate. Hard to tell for certain. Once the angle of the sun went down things to cooled down, the core stayed wet… creating a soggy environment …and that’s where we are at this point.

To help would chock up one side of the pot about 2 cm until the roots are washed. This will lower the water table and help keep the tree dry. Also would pour 1:2 H2O2:H2O solution through the root ball instead of watering next time the plant clearly needs water.

Root washing is a late winter early spring routine and the plant will need to be protected from freezing and full sun for about 3 weeks. From then on morning sun afternoon open shade.

btw. We use 90:10+5. Kanumaumice+5% Biochar on our azaleas.

Once the plant is in kanuma one can water as much as one wants. With ordinary care the plant will not get overwatered. Will not get rid of root rot though, but with luck the tree is only stressed.

Here is a thread on rootwashing.

Pots. Here’s an image of azaleas, many in Tokaname pots. All are in kanuma based media except anyone in a nursery pot.



Timing on winter prep. This procedure is done in November prior to winter storage here to most azaleas. It’s in winter storage where the threat of fungus accelerates, especially. When ventilation is insufficient. Your climate is very similar to ours. (Interesting about Dorset. How about sending me the page in Droste’s book so I can see the context.)

btw: Some azaleas need prep earlier than others. Kazan is one. Here’s what to look for.

First is an image of Issho no Haru clearly needing prep. Note the discolored leaves. (These examples are azaleas with yellow fall leaves, there are also azaleas with red, yellow/orange or purplish fall leaves.



Second image of two azaleas that are basically ready too. Not discolored leas, yet not as many… both will have prep done immediately after we finish inventory next week. Also note how crowded the foliage looks. Not for long.,



Best,
DSD sends

 

[NeedlesAndLeaves]

Thanks a lot for clearing all those things out !

(Interesting about Dorset. How about sending me the page in Droste’s book so I can see the context.)

I will add some pictures with the pages of the book where it mentions to remove the “thieves” around the flowerbuds in spring. There is no mention of it in autumn.

I could not find any related information in this book about the leafcolour which I why I reached out to the forum.

It also mentions that Kanuma has an increased PH value, but that is probably an overlooked mistake when it was published.
Beautiful book btw

Thanks again for taking the time and thinking along in this matter!

Grz Jasper

 

[Glaucus]

It says "verhoogde zuurtegraad' in Dutch. So of course a translation error as an increase in acidity is a decrease in pH. They flipped it around.
I am pretty sure kanuma and akadama have the same pH, which is way higher than that of peat, which could be as low as 3.5, but usually 4.5 to 5.5. And 4.5 to 6 is what people usually recommend for all rhododendron and azaleas. But with chelated iron, they can do well in neutral pH soils.

Kokuryu can have a very strong autumn colour. If it appears, it will be obvious. Some of mine have turned red already. But others, not yet. I have ave Kokuryu myself and I remember that in one year, it stayed quite green.
Autumn colour of individuals may differ from the cultivar general trait.

 

[Juanmi]

I am pretty sure kanuma and akadama have the same pH, which is way higher than that of peat, which could be as low as 3.5, but usually 4.5 to 5.5. And 4.5 to 6 is what people usually recommend for all rhododendron and azaleas. But with chelated iron, they can do well in neutral pH soils.

Out of curiosity I wanted to check that.
It turns out Akadama has between 6.0 - 6.5 ph and Kanuma has 5.5 - 6.0 ph, so yeah, not that far apart after all.

And Kiryuzuna would be at 5.5 - 6.5 ph

Interesting, I found this on a Japanese website, I'll leave the link here if someone wants to check it out, they include other types of soil as well.

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