Berra's Satsuki Nyohozan

[Berra]

Hello! Last year i bought myself a satsuki azalea. It seems to have survived this year's mild Winter where I live (Scandinavia). This is My first azalea, most of my other trees are pines.

Earlier this spring I repotted the tree using 100% kanuma, I didnt cut back roots much (at all) since the tree was not root bound, however I bare rooted it. And in hindsight i might not have needed to repot even though the old soil seemed to not let water through as easily as the new soil does.

I cut some rather thin branches back from the top of the tree. I also gave it nutrition (rhododendron fertilizer powder/grain), which however seemed to clog the new soil up a bit. After a few weeks i noticed the tips of the leafs, predominantly in the top of the tree, turning crispy dry and orange.

I then thought that perhaps that could be fertilizer burn, and i removed the top layer of the soil and replaced it with more kanuma. It might also be sun burn. I have so far kept the tree with partial shade, evening Sun only.

I water it once the top of the kanuma starts turning dry.

I think I have stressed the tree with the repotting and pruning, so I removed most of the flower buds a couple of weeks ago.

Now to my question, should I keep the tree in full shade until it recovers?

Could it be something else that I miss out on, that is causing these orange tips?

Thankful for advice

 

[Berra]

Oh yeah, forgot to mention that the tap water where i live is slightly alklaine, cannot do much about that and since i only have a balcony, collecting rain water is challenging

 

[Harunobu]

I wouldn't call those 'orange tips'. Those are dead tips. I think fertilizer burn is very likely the cause, as you describe it occurred after you applied fertilizer. Not sure what to advice besides putting it in the shade. I guess the good thing, kinda, is that only half the leaves are burned. Did this stabilize? Or is it being burned further? If you really did add way too much fertilizer, and I assume it was chemical, then one at some point can make a case for getting it out of the pot and rinsing out all the fertilizer, so it won't burn more. Not really sure if that is the best option.

The alternative is that your organic fertilized clogged up the kanuma and it blocked water from getting to the roots?

But the reason I would say this is likely not a lack of water is that lack of water would lead your new shoots to go limp, then dry out and fry, while old leaves are more robust, don't really get damaged by lack of water, until it gets really bad. Yet your new shoots are still alive, except for the tips. And the same burns are on the old leaves. And you say it was in partial shade. So hard to see how the sun could burn it like this. It would be worse if your new shoots would be limp and dead AND old leaves also burned. So to me that indicates that only those tips of the leaves burned/had too much water withdrawn because of reverse osmosis, and not things like roots or entire branches.

I think I would put it in full shade, try to keep the kanuma somewhat moist, but not water too much. Excess of water now does not solve a lack of water in the tissue earlier. You say you removed the top layer with kanuma to try to remove the fertilizer. Now that it has burned but it does have shade and the roots are taking up water again and assuming the fertilizer is diluted, it doesn't need too much water. I think there will be people saying you should put a bag around the pot, or towers, or sphagnum moss, to keep humidity of the air inside the root ball higher.

I wouldn't worry too much about the tap water. Ignoring the tips, it also looks a bit leggy. Not that much new growth and it seems really fresh and light green. It looks just as a bunch small cuttings I received years ago. And they look completely different now that they are doing well in the garden. You really need to find a way to let this recover and grow grow grow a whole bunch.

 

[Berra]

Hey thanks so much for the reply!!

The fertilizer I used is a mix of chemical and organic. The Specs:

NPK 6-2-4, (Mg) 1%, (Fe) 1%, (Cu), (B).

I believe the leaf dieback has stabilized - I have not seen any expansion of the dead areas in maybe 3 weeks

Would it stress the roots too much if I lift it out of the box to look for more fertilizer? I guess its a trade off if more fertilizer is lurking further down.

Yes - making it less leggy is definitely the long term goal.

 

[Harunobu]

So those pictures were taken today? Or 3 weeks ago? If it didn't get worse, I wouldn't intervene anymore. I guess you did a good rinse after you saw the first damage and suspected the fertilizer. It would be then the chemical water-soluble part of your fertilizer creating water with very high osmotic value in the root ball. This desiccates the plant tissue, as reverse osmosis draws water out of the plant, where the osmotic value is lower, and into the root, to dilute out the chemical fertilizer concentration.

If you wash the root ball, it will dilute the chemical fertilizer by a lot. And the cause of your problem should be fixed. Whether this specific fertilizer causes some issue in combination with the kanuma, or if it is just you have applied too much, you kind of have to figure out yourself. You don't really want to clog up things with organic fertilizer while at the same time the chemical/salt component is burning the roots. The organic fertilizer that is now still there, probably harmless. It is not going to cause new burns because it cannot all suddenly become water-soluble at the same time. And I can't imagine how it is severely clogging stuff up after 3 weeks, after removing a bunch already.

You could just use the Japanese approach to fertilize satsuki in the future, by making cakes of oilseed rape and putting them on top of the kanuma.

I have also seen people put the organic fertilizer in some type of paper teabag. I like that a lot more than weighing off some concentration of chemical fertilizer, diluting it, and then adding it to the plant/bonsai weekly.

Also note that your bonsai on your bonsai in Scandinavia will need much less fertilizer than one in peak growth in a greenhouse in Japan. Azalea don't require much fertilizer. And your tree was imported, which means it went through the import quarantine thingy. I don't think they have to be bare-rooted for that, but I think they do the aggressive pruning and root work. So once you get it, it won't be growing like crazy. And it won't be growing like crazy for as long, because you aren't in zone 8 inside a greenhouse. So the amount of growth you get, and therefore the amount of fertilizer you need, is much less. I think all these clays they use in Japan for bonsai do in fact contain organic matter. I have seen it described that kanuma contains Al–humus complexes. And that means as your kanuma decomposes, the organic matter in there, and the nitrogen and whatever else is still in there, is also released. So tap water for trace elements and the soil itself do provide some fertilizer. But at some point, the plant is growing so much, you need more. But if you have a leggy plant in fresh kanuma, I wouldn't fertilize unless there is something like a chlorosis/visible deficiency. It is a mineral supplement, not a food source. But it seems that in the bonsai world, many people really like the idea of fertilizing heavily to maximize results.

 

[Berra]

Great info, much appreciated! The pics were taken today. The plant has been looking like that since mid May I would say, but today I got the idea to ask here

 

[Deep Sea Diver]

Great info, much appreciated! The pics were taken today. The plant has been looking like that since mid May I would say, but today I got the idea to ask here

I wouldn't call those 'orange tips'. Those are dead tips. I think fertilizer burn is very likely the cause, as you describe it occurred after you applied fertilizer. Not sure what to advice besides putting it in the shade. I guess the good thing, kinda, is that only half the leaves are burned. Did this stabilize? Or is it being burned further? If you really did add way too much fertilizer, and I assume it was chemical, then one at some point can make a case for getting it out of the pot and rinsing out all the fertilizer, so it won't burn more. Not really sure if that is the best option.

The alternative is that your organic fertilized clogged up the kanuma and it blocked water from getting to the roots?

I think I would put it in full shade, try to keep the kanuma somewhat moist, but not water too much. Excess of water now does not solve a lack of water in the tissue earlier. You say you removed the top layer with kanuma to try to remove the fertilizer. Now that it has burned but it does have shade and the roots are taking up water again and assuming the fertilizer is diluted, it doesn't need too much water. I think there will be people saying you should put a bag around the pot, or towers, or sphagnum moss, to keep humidity of the air inside the root ball higher.

Hey there, not sure I concur on focusing on fertilizer at all.

Let's use a bit of Occam's Razor on this issue.... these plants are on a balcony..... they don't look choloritic... so the simplest answer appears to be that they got a bit of sun scald. Happens a lot here in the PacNW to my potted satsuki's if I don't watch out. The fertilizer mix is ok by me for azaleas... in fact its the same basic formula as Osmocote Plus without the micronutrients?

Don't get me wrong, over fertilizing can kill azaleas, in fact a number of authors list that as one of the prime ways homeowners kill their azaleas. It just doesn't look like that to me at this point....

Satsuki's like morning sun and also its helpful to have exposure to the last couple hours of sunlight. They also can thrive in filtered sunlight all day. You could actually construct a sunscreen an/or a slatted box, propped off the ground a couple three cms to improve the air flow, to put over your satsuki.

When you water your satsukis, may sure you water them thoroughly, leaves too, and flush the water through the pot thoroughly.

As far as fertilizer goes, easy does it. If you continue to use that fertilizer as your base three times a year, you can use Miracid every couple of weeks to supplement. Follow the directions on dilution for now.

If you want to get rid of the leggy growth, prune these areas down to two horizontal stems with only two leafs from each blossom site in the next month. If they are healthy they'll back bud in a couple three weeks. If they are way out of the profile, you can cut these off just under the profile. I'd recommend do the minimum possible until you get a good year under your belt on this plant.

Two remaining questions.
1. What exactly is your water's pH?
2. What named variety of satsuki do you have?

Cheers
DSD sends

 

[Berra]

(one more option could be frost damage, though I was careful to bring this plant indoors during night early May when we had frost here)

Not sure if Osmocote Plus is available in Europe, a quick googling tells me it is 10-11-18+2MgO+TE? Also not sure how to compare that mix to what I used.

I live in the Stockholm area, so further north than you - but we do get sun here too of course. Will look into building some sort of sunscreen for this tree!

1. According to the local government, it is supposed to be 6,5 to 9,5. Did a quick measurement with a rather cheap PH indicator just now, it shows somewhere between 8 and 9 from what I can tell.
2. Nyohozan (https://satsukimania.com/en/varieties/239-nyohozan)

Don't have the guts to cut more this year. It will be a long term project

 

[sorce]

Welcome to Crazy!

I'm happy no one is talking about fungus!
Though I'm not educated enough on it to know if it is not that, I don't think it is.

Seems a sun thing. Has me thinking if this doesn't fit into the same category as the yellow edged boxwood leaves. Where it's not too much sun, but too much water in too much sun, that leads to too much transpiration, that wears out leaves. Side benefit for the tree, more shade, less transpiration.

So oddly enough, lowering available water, a highly counterintuitive action, can fix that problem.

Safer to increase shade though.

I think this has thoroughly changed my mind on removing those browned leaves. The tree needs them still, that's why it made them, to shade itself and work less. California ass Bush!

If we want perfectly pretty, we have to prevent this ugly, but removing the ugly after it happens, is harmful to the tree. Unless we are of a mind to prevent it further. I bet a lot of trees died not paying attention to this, or worse, removing the leaves cuzz "it's a fungus!".

Cheers.

Sorce

 

[Deep Sea Diver]

Hmm frost burn here would cause loss of many leaves all at once, but it’s an Ok thought.
The Osmocote Plus here is 15-9-12 plus Mg, S, plus TE: B, Cu, Fe,Mg & Mo & Zn so pretty close to your fertilizer.
PH is perhaps more concerning, but you Satsuki is not choloritic, which would be a good indication of water pH having an impact. I think the kanuma is helping a lot to even things out. However, you may need to repot sooner than the max of 3 years if the leaves start showing cholorosis (sp).
It takes a brave, thoughtful person to not to cut sometimes!
Nice variety!
cheers
DSD sends

 

[Daniel son STL]

That’s brown, dead leaf tips. Looks like sun scorch to me. I got the same thing on my azelea after a hot afternoon of direct sun.

 

[Harunobu]

If it is sun damage, it isn't through drought/lack of water but through temperature? Could be on a potted plant surrounded by concrete? I don't have potted plants on a balcony, so not sure what kind of dynamic that can create. I don't think it is drought/lack of water because like I said, that will crisp the new growth completely before affecting the old growth, from my experience. And it only got sun in the evening? Well, you do have long evenings now. Those two things is kind of why I prefer one theory over the other.

As for frost, Nyohozan is a variation of Kozan. It should be one of the more winter-hardy varieties. But a late frost spell can damage fresh new shoots. I have only seen a late frost spell completely brown up the new growth, without affecting the plant otherwise. A late frost spell here killed almost all flowers on the plum tree right next to my azalea. But only my Hakurei had new shoots that were brown. And I think that was because it started growing early. Now potted plants do start growing way earlier than those in the ground, and will therefore be more susceptible to frost coming and killing the new shoots. But your picture does not match my experience of what frost does to new shoots in late April. Why would it only affect the tips, for example? And you said you moved it inside. So it didn't even experience the frost?

I agree that since you cannot be sure you shouldn't take an action that would be better under the assuming 'fertilizer burn' but bad under the assumption 'sun burn', or vice versa. I would keep the damaged leaves because only the tips are dead. The plant can still use the live parts. And putting it in a spot with reduced respiration, to lower the burden on the roots, I agree with that.

I don't think the NPK formula matters at all for fertilizer burn. What matters is if it contains water-soluble salts that increase the osmotic value. Whether they are potassium salts, phosphate salts, ammonium salts, or some water-soluble organic molecule like urea. I bought a bottle of Osmocote in the Netherlands a few years ago. It has some coating around them than makes them slow release. I see similar pebbles in almost every azalea I buy from nurseries nowadays. I put a few in my potting mix when I plant out my seedlings. Not exactly sure how it works or how to properly use it. But the coating is supposed to make the pebbles a slow release fertilizer. And not sure if it is the perfect tool for bonsai, as you are kind of trying to control things yourself by using skill and extra care.

I see azalea people in the US always talk about using Miracid. I don't think you can buy it in Europe. And it helps keep the soil acidic in places where naturally it isn't, as well as being a fertilizer. Not sure what is inside or what the mechanism is.

 

[Berra]

Great discussion here. I will take the collected advice to put it in the most shady corner of our balcony, where wind shelters help keep the sun out. Additionally I will build a simple sunscreen for it. Then I will get back when I can report the results/findings/developments.

Hmm @Harunobu I did keep it in a corner of the balcony where it only got sun from 4-5 pm onwards - but that corner also has concrete walls - didn't think about that actually. And as you say - we have sun until maybe 10pm now.

 

[Leo in N E Illinois]

@Berra - Sun until 10 pm? You are indeed pretty far north. That is 5 hours of sun per day if sun hits your balcony at 5pm.

I do think sunburn, not frost, is one possible cause of your problem. But your plant has already adapted to the "new in May" light levels, your new growth is just fine. No need to make changes in sun exposure. 5 hours of low late afternoon sun is just fine. The fact that you are growing on a balcony suggests you do not have a balcony that faces east. So west will have to do. This is just fine.

Looking at your fertilizer numbers, I don't think there is any problem. I would continue using that fertilizer. The amount you used was possibly too high. If the damage was caused by excess fertilizer it is only due to the amount applied. In bonsai we want healthy growth, but we do not need overly long, excessively vigorous growth. The fertilizer companies are in the business of selling fertilizer. Their recommended dose rates are probably at the higher end of what is safe for plants. And since for bonsai we prefer growth with shorter internodes and smaller leaves, excess fertilizer is counterproductive. I would take the label directions, and cut them in half. Follow the lighter regime for fertilizing. It won't hurt to be on the light side. New growth looks fine, so you fixed what ever the problem was. Next time the tree is due for a second application of fertilizer just cut the dose to half of the recommended strength.

Last. Your municipal water pH is a red herring. A trip down a blind alley. Do not worry about water pH. All municipal water is required by law to be buffered to a pH between 8 - 9 pH in order to prevent lead (Pb) from leaching from pipes, supply lines, solder joints, and brass fittings & valves. If the municipal water pH ever dropped below 7.8 pH, there is a real risk of serious lead poisoning of all the children living in the municipal water district. In fact, if your municipal water has a pH of less than 7.5, someone is trying to give you lead poisoning, and you should immediately report this to the city government, the police and environmental protection services. So always, municipal water supply will measure pH of 8.0 or higher.

A pH measurement does not measure the actual issue. The issue is calcium content of the water. The correct measurement to get at calcium content is TOTAL ALKALINITY, which is reported in milligrams per liter as calcium carbonate. It can be reported as parts per million as calcium carbonate. In USA municipalities over a certain population level are required to publish their annual water analysis report. I suspect the same holds in Sweden. Look for your municipal report. If you water has a total alkalinity less than 600 mg/liter as Calcium carbonate, the water is generally safe to use to water plants. Now ideally if the total alkalinity is between 0 to 200 mg / liter as calcium carbonate, you need to do nothing for your azalea. If your alkalinity is between 200 mg/liter through 600 mg/liter as calcium carbonate, one should use a fertilizer that in USA is described as being for acid loving plants. In the EU it would be a fertilizer that does not contain added calcium, does not contain calcium nitrate, nor any other salt of calcium. In these fertilizers often the nitrogen source in ammonium salts. So ammonium nitrate, ammonium sulfate and other ammonia salts. Another tactic for handling water with total alkalinity over 200 mg/liter, is to use soil sulfur additives. Powdered elemental sulfur will slowly dissolve and make various sulfurous acids, not sulfuric acids, in the soil water film. These are weak acids and serve to bind up excess calcium. Using about 5 ml by volume of powdered elemental sulfur to a liter by volume of potting media, will be about right. Powdered elemental sulfur is available from garden supply stores, especially where they cater to organic vegetable growing. Elemental sulfur can come in a OMRI grade, acceptable for organic vegetable growing. This needs to be dosed as a top dressing once a year. This is elemental sulfur for acidifying soils. There is a second grade available, a very fine grind of elemental sulfur that is intended for spraying as a fungicide. This finer grind is the same material, and can be used. But needs to be dosed at about 1/3rd the rate, but because it dissolves faster, it can be dosed 3 times over the course of the year, rather than just once per year.

Between now and when you find your municipal water report, again looking at your new growth, I wager your Stoholm, Sweden municipal water falls in the acceptable range, probably closer to 200 mg/liter as calcium carbonate rather than above the 600 mg / liter level. Because your new growth is clean, I would simply not worry about your municipal water. The above is how you would handle water if it is indeed a problem.

So to sum up what I see, your new growth is healthy, current conditions then are acceptable. Make no further changes. In the future, use a lower dose rate with your fertilizer. And don't worry. I think your azalea will be fine. You have a great variety of Satsuki there.

Happy growing.

 

[Stan Kengai]

Dead leaf tips on azalea is almost always a sign of too much water. What the cause is I do not know, but the soil is/was staying too wet. If it has stabilized, I would guess your problem was solved. But now you have to figure out what the problem was, so that you can avoid it in the future.

 

[Harunobu]

With 'too much water', do you mean root rot/phytophthora?

 

[Stan Kengai]

With 'too much water', do you mean root rot/phytophthora?

No, not necessarily, and doubtful due to it stabilizing. It could be overpotting, or too many roots removed during repotting (leading to overwatering), or poor soil, or just watering too frequently. I have personally seen this response from using poor soil while experimenting, after root damage from lack of water during vacation, and from overpotting.

 

[Deep Sea Diver]

Wow! So that’s just about the entire gamut possible short of @sorce’s fungus!

I did some research and asking around to azalea folks out here and the only other things that seems to be missing from a complete list Of possibilities are wind burn and under watering.

I like the overwatering idea, a couple folks here coupled that with root rot too. One source I found claims that over fertilization causes the majority of azalea/Rhody demise.

Just reflecting in the open of the things I’ve found in gardening and bonsai in specific is the tireless search for the ”sole cause” and often end up back to the thought that there may be more than one cause... so it helps to know the whole range of probables. For me, is a great forum to gather that wide ranging practical and theoretical knowledge information base I need to do better by my trees and plants.

Cheers
DSD sends

(Incidentally, the pH of Seattle area water is between 7.5 to 8.5 and at my house regularly rocks in between 7.6-7.8. Here’s a good graphic report on corrosion control and pH on Seattle’s water supply should anyone care to peruse it. Thanks @Leo!

 

[Harunobu]

I agree on the water pH and water hardness thing. That's a good point. People think pH is kind of like a set property of water. But there are actually two properties to pH; the actual value, and how easy or hard it is to change that value. We all know that when water evaporates, it leaves minerals, mostly chalk. And chalk/CaCO3 will make the soil more basic over time, as the carbonate ion can scavenge free H+ ions and even potentially remove them permanently from the soil when the soil releases CO2 and H2O (when (CO3)-2 + 2H2 <--> CO2 + H2O). And that's what happens if you put really hard/carbonate-rich water into acidic soil (which azalea require). So if you want to figure out how important it is to collect rainwater vs using tapwater, check the water hardness or concentration of CaCO3

But that's a detour.

The overwatering theory could work. What do you think would be the mechanism? To me, it would have to be that the roots have a lot of water around them, so they decide to limit water uptake. But then suddenly the balcony is receiving full sun and the leaves start evaporating a lot of water. But the roots cannot adapt quickly enough. So the tips desiccate and get burned.

The sun burn thing, yes it can happen while the plant has enough water. But I have observed this as a sort of blister and hardening of older leaves, them becoming a bit brown in the center. And it doesn't affect new leaves or burn tips. Not sure why this happens only to older leaves. I imagine that he new leaves evaporate water more easily, cooling them. But you would think the sun burn unrelated to dessication would be UV-related and not temperature-related.

Since the tips are burned I still stand by the idea that the water column was pulled downwards, back into the roots, desiccating the tips of the leaves.

I agree it isn't root rot because that results in the death of an entire branch. Sometimes starting with damage at the base of the leaf. And other branches that don't have their part of the roots rotted away yet will look normal.

 

[Berra]

It will take me a while to consume and fully understand and evaluate all this info in the thread. For what its worth, I looked up the water's properties: it is reported as 4-6 dH. This should be "soft to moderately hard"