What Am I Doing Wrong with my Satsukis

Time Wizard

Sapling
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Location
Southern California
USDA Zone
9a
I live in southern California in the desert, zone 9. When spring came around I went down to Nuccio's and picked up about 16 satsuki azaleas, all different cultivars. They seemed to be doing fine up until about a month or so ago. The leaves on just about all of them are starting to turn brown and die and I can't figure out why. The first picture below is Eikan, the second is Kikusui. I'll refrain from posting any more pictures because they all look exactly the same, just varying severity of brown leaf tips. I have them all on the west side of my house where they get full sun from about 9:00 AM to 2:00 PM, then they're shaded by the neighbor's tree overhead. A couple months ago, however, I put up a 50% shade cloth, so lately they're getting 50% shade from 9 to 2. They are all on a bench up off the ground. The temperatures in summer here routinely get above 115 F, as evidenced by the screenshot below. I live about 2 hours north of Nuccio's, so I can't imagine the climate is the issue. They grow just fine over there.

I have about half of my satsukis in the original soil still in their 1 gal black plastic pots (such as the Eikan pictured). A handful I bare rooted and repotted in late spring into clay pots with about 70% kanuma, 15% shredded sphagnum moss, and 15% peat moss. These include Kimi Maru, Kaze, Ukigumo no Tsuki, and Green Glow. Yes, I am aware Green Glow is not a satsuki. These are all doing pretty well, only a few brown leaf tips except for Kaze which was doing pretty poorly even right after I repotted it. There's a few small buds on it, but I'm pretty sure that one's dead already. Another 4 of them I slipped potted about two weeks ago into either 3 gal black plastic pots or clay pots. These include Shinnyo no Hikari, the Kikusui pictured, Kongo no Hikari, and a fourth cultivar that's slipping my mind at the moment. They were slip potted into a mixture of about 60% peat moss and 40% pumice. These weren't doing too terribly until I slip potted them, then they all started turning brown.

I find that the satsukis in kanuma usually need to be watered about once a day. Most of the time, these will have the soil just barely dry on the top when I come home from work in the afternoon, so I water them. Sometimes, they'll still be just barely moist on top. The ones in their original pots/peat get watered about once every 3-5 days or so. I will wait for the soil to be dry on top, then I'll pick each one up and feel how light it is. If it's feeling pretty light, I'll water it. I've noticed that even when the soil becomes dry on top, it's still soaking wet below so I wait until it feels like a good amount of the water has evaporated until watering it again. The slip potted satsukis are a little too big and awkward to check by picking them up, so I go off of how dry the soil is on top. These go maybe an extra day before being watered again as compared to the 1 gal satsukis.

As for fertilizer, I have some bio gold nuggets on a few of the satsukis potted up in kanuma. I am using a more run of the mill rhododendron/azalea/camellia fertilizer for everything else, maybe a tablespoon or so on top of the soil of most of the rest. There's probably a couple of these that i haven't fertilized at all.

Please help me figure out why my satsukis are dying. If there is any other information that might be helpful, I will be happy to provide it.

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115F/46C is extremely hot. A lot of parts of the world are really hot right now. I do not know how Nuccio's manages their azalea in those temperatures. You say you are 2 hours north of them. But does that mean your climate is cooler? I can imagine driving 2 hours from the coast into the desert in Cali can make things a lot harsher on plants. Probably, it is similar, right?

Watering once a day for an azalea in kanuma during 46C temperatures doesn't seem like a lot. Watering 2x seems needed, I would say.
Also, I wouldn't fertilize above 90F/32C. I have watered twice a day for plants in peat/kanuma with 30 to 30C temperatures.

I think your best bet is to ask Nuccio's how they deal with Cali hot summers.
 
115F/46C is extremely hot. A lot of parts of the world are really hot right now. I do not know how Nuccio's manages their azalea in those temperatures. You say you are 2 hours north of them. But does that mean your climate is cooler? I can imagine driving 2 hours from the coast into the desert in Cali can make things a lot harsher on plants. Probably, it is similar, right?

Watering once a day for an azalea in kanuma during 46C temperatures doesn't seem like a lot. Watering 2x seems needed, I would say.
Also, I wouldn't fertilize above 90F/32C. I have watered twice a day for plants in peat/kanuma with 30 to 30C temperatures.

I think your best bet is to ask Nuccio's how they deal with Cali hot summers.
Thanks for the reply Glaucus. I probably live far enough away from Nuccio's that the climate is at least somewhat different, but I can't imagine that's the only reason why my satsukis are struggling. I've seen a lot of people in milder climates say that they water their trees two or even three times a day in the summer and that seems crazy to me. If I were to water the satsukis I have potted in kanuma twice a day they would constantly be soaking wet. The fertilizer might be the issue, but I checked a few minutes ago and some of the ones that are struggling have been fertilized very lightly or not at all. Regardless, i can see how fertilizing in such high temperatures wouldn't be great.
 
I am not saying that the fertilizer caused your problems. I did read your post and you said that unfertilized plants had the same issue. So fertilzier cannot be the reason. It is just that above 90 to 95F, the plants shut down anyway. And at those tmeepratures microbial activity also increases, leading to more decomposition of organic fertilizer and an increase in salts/water-soluble minerals. A that together with the potential lack of water stress, you may be releasing too much nutrients. So it is better to not apply fertilizer. And remove the fertilizer cakes you have on the soil, if you do it the Japanese style.

I don't see how a plant in 70% kanuma can ever be soaking wet during summer. Water falls right through kanuma. And while it does have water retention, it is far less than say peat or vermiculite.
Does the kanuma ever turn white/cream coloured? Or does it stay ye;;ow call the time?

People often talk about azaleas and overwatering. However, even during late winters when temperatures are at 6 to 14C, when it may rain here 10 to 20mm a couple of days in a row, and the plants are dormant and in 66% peat/organic material, there is no root rot. Even in a 1000+ seedlings and cuttings in 7cm to 10cm pots. So I just don't believe satsuki in kanuma can be overwatered, period. Unless the kanuma went to durst.
Yakushima island, where satsuki grow naturally, gets 510mm rain in June. Altadena, CA, where Nuccios is, they get 1.5mm in June. That's a 340 time difference. Of course, you would water. But just to show how crazy the rainfall difference is.
Now satsuki don't need 512mm of rain in June during 30C temperatures. But they need to be moist if it is 115F/46C. They can't be dry.
I believe it has been unusually hot for you in Cali as well. And personally I don't really understand how Nuccio can grow satsuki that successfully in a climate where it gets to be 115F regularly, and where it rains less than 1mm in July and August.
And I don't even know if kanuma is viable as a growing medium for satsuki under those conditions.

And besides the water inside the plant itself, throwing water that is 8C or 12C on it 2 or 3 times a day is a great way to keep the plants cool when you have a 115F heatwave. And when you water them, be sure it is at least 2 to maybe 10mm worth of rain that they are getting. In bonsai, too much water can lead to too little oxygen. But for satsuki as long as the soil in the pot is still good, there should be oxygen available to the roots. This is one reason why you always put azalea in an airy potting mix, even forf non-bonsai. That way, you can water without ever risking choking the roots by them being too wet.
I would even try things like putting wet towers around the pots, to keep them cool.

If you ask Nuccio's what percent of shade cloth they use and how often they water, you are closer to your answer.
 
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You are doing remarkably well with most of your satsuki considering the climate the trees are in. It’s over the edge.

Two things I noticed

About the casualties. Slip potting can be deadly unless one uses exactly the same media. The imbalance between medias draws water in our out of the core media. Both cases are detrimental to the tree. In one root root, in the other desiccation. Both initially look similarly .. dying leaf tips. Fix by matching the media exactly.

Your climate is substantially different then Alahambra, where Nuccios is located. This is their forecast. SoCal climatic zombies are stacked very close together. Also the 2012 USDA Plant hardiness zones are no longer valid, at least 1/2 to a full zone higher

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I’ve been thinking ways to help give your trees more of an edge. Got a thought. Misting could help. Perhaps building a gravel bed lined with plastic under the benches that catches watering overflow and evaporates during the day to mist and create a slightly lower temperature under the benches?

Cheers
DSD sends
 
Agree with Deep Sea Diver that improving the micro climate by raising humidity would be key. Japan is also hot (although not as hot as your conditions) but with high humidity. Repotting outside of winter is probably not suitable for you and I would even say your local climate might be a bit rough on Satsuki and it might not be the tree for you. Repot only at or just before the first flush of vegetative growth in winter so that the plants have time to adjust and grow new roots,
 
Could pH cause this? Water supply is often high pH (alkaline) but azaleas like acid soil. Check soil pH to see whether soil is acid or alkaline now.
In addition to the heat, pH is surely an issue!!
 
Please clarify
The ones repotted into kanuma and sphagnum moss are doing OK but the ones on the original soil are not?

The fact that you have to water some every 3 to 5 days in your climate is a huge red flag for me. I think those are staying too wet which azaleas don't like.

Try the chopstick method to monitor soil moisture. It works really good to see what he soil moisture is like below the surface.

I am in a lot cooler area than you. My azaleas are in 100% kanuma or 50/50 kanuma and pumice. I water every day even here, sometimes twice if it's above 90/95.

The slip potting in the heat you've been having probably didn't help.
 
pH doesn't do this. Additionally, some are in peat. Even if you use very hard water on peat, it will take a while for the lime buildup to change the pH from 5 to something like 7.
Then, you will see chlorososis or very light green leaves. These are tips that are burned. That is because of lack of water.
 
Water them every day, and keep them under shade cloth.
Humidity is key, as said above.
 
Check your water. Particularly for sodium. SoCal water is the worst. You probably have highly alkaline water in the 8.5pH range, and it will be high in dissolved salts. All water districts in California have to issue annual water quality reports - just look yours up.

I believe this particular damage is mostly heat/wind caused. Not only do you need to shade your azaleas, but you need to protect them from the wind, particularly if you get Santa Anas or strong winds off the desert that are low humidity. If the dry winds are blowing you will get leaf tip scorch because a tree simply can't provide water fast enough to keep the tips hydrated. Note how the inner leaves are not showing as much/any damage. That generally indicates the cause is mostly environmental because the outer leaves are getting the worst of it, while the inner leaves are protected. However salts / over-fertilizing can also cause dehydration in plant leaf tips, so it is best to protect the tree AND check your water.
 
Yes, high mineral content/TDS/EC of the water will make it harder for the plants to take up water. It, together with additional fertilizer or decompsotion of organic matter, can put more osmotic stress on the roots. Which can make the dry hot weather worse.
 
I just looked up the water report for the town I live in. Apparently the pH of the water here is 8.6. Is there anything I can do about that? I don't really have a way to filter large amounts of water for my trees and needless to say it doesn't rain here.
 
Do they add sodium hydroxide to prevent water pipe corrosion?

We just had a thread about it here:

tldr is; if it is calcium carbonate that is the problem, use RO.
If it is high pH because of added sodium hydroxide, try citric acid-based products like pH Down together with a pH tester.

Would Nuccio use the wale tap water? Ask them if they use tap water. Probably, they'd be using well water for a nursery, right?
But maybe the area is so dry that isn't even a thing, not sure.

Satsuki varieties like Wakaebisu, Takasago, Gumpo and Asahizuru might do better in hot weather than Kikusui Kimimaru. Eikan should be intermediate.
Additionally, I would expect Nuccio's own satsuki and Belgian indica hybrids to perform much better in SoCal.
I remember them commenting on which varieties did least worse for them during a summer heatwave.

Someone should experiment by breeding in more species Rhododendron scabrum to get more drought and heat tolerance. Or even that azalea from the Philippine, whose species name escapes me.
 
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This is what two of my azaleas potted up in kanuma look like. Kimi Maru on the left, Green Glow on the right. The Kimi Maru is completely dry on top, but if I were to brush the very top layer away it would still be the wet yellow color underneath. This is about when I would water this one. The Green Glow on the right is still mostly moist/yellow on top. I would hold off on watering this one and check it later in the day. Should they be getting watered more frequently than this?

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This is what two of my azaleas potted up in kanuma look like. Kimi Maru on the left, Green Glow on the right. The Kimi Maru is completely dry on top, but if I were to brush the very top layer away it would still be the wet yellow color underneath. This is about when I would water this one. The Green Glow on the right is still mostly moist/yellow on top. I would hold off on watering this one and check it later in the day. Should they be getting watered more frequently than this?

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Please try the chopstick method.

Stick a wooden chopstick or piece of a dowel in the pot as deep as you can and leave it there. Take it out and check it every day. Water when it is almost dry. Just looking at the top of the soil won't tell you what is happening deep in the pot.
 
This is what two of my azaleas potted up in kanuma look like. Kimi Maru on the left, Green Glow on the right. The Kimi Maru is completely dry on top, but if I were to brush the very top layer away it would still be the wet yellow color underneath. This is about when I would water this one. The Green Glow on the right is still mostly moist/yellow on top. I would hold off on watering this one and check it later in the day. Should they be getting watered more frequently than this?

The way you word it in that post and how it is pictured, you are watering perfectly. The issue is that on just one of those days with 100F+ temperatures, just before you come home, they are drier than what you describe here.
If it happened every day, your plants would already be dead, of course. I also don't see brown tips on those two plants. But if it happens once, you will see the brown tips a few days later
These plants would definitely benefit from spaying water on their foliage and on the surface of their pots midday on 100F+ days. But if you are at work, you can't do that, of course.
So given your weather, I think you will just water every day right as you return from work. And then check in the morning before you leave and maybe water again. Or at least mist everything.
You can't really say "ok this hasn't completely dried out yet, I will skip it and water in the evening" when it is going to be a 100F+ day.

Did you ever see any new fresh shoots droop/go limp/lose turgor pressure? Because this season I had a bunch of satsuki myself that somehow missed watering, and they go limp, but they didn't get their tips burned on those.
If their new fresh growth never went limp, but the tips are burned, then maybe it is the mineral content in the water after all? Older more lignified growth may not go limp but still get dehydrated.
It is just nice that the plant gives you a warning sign when it does have the tender new growth.

I am not sure what a satsuki does if it is just constantly too hot, despite the soil being most. I am sure they won't like sitting in 50C wet peat.
This is where maybe overpotting can be a thing. The plant will cool itself by evaporating water. And then you can add new cool water to the pot maybe 3 times a day. And it will pretty quickly draw up that water and evaporate it.
But if a plant is overpotted, the moisture will stay wet in the pot, not go to the roots or leaves. It will have to evaporate from the pot directly.
The Green Glow one doesn't have a ton of foliage compared to pot volume.
It is not necessarily bad to overpot. But growing a smaller plant in a pot at 115F is harder than growing a larger plant in a larger pot.
May still be better to have a small plant in a large pot than a small plant in a small pot. Small plants in small pots are first at risk for drying out and getting too hot.
Keeping the roots cool maybe just as important as keeping the plant hydrated.
 
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First off recall the big picture….these high temperatures are throwing the plants photosynthesis, transpiration and rhizosphere nutrient systems out of whack. So things are not so obvious.

So one has to first ask, “Were these symptoms showing when the temperatures weren’t over 92ish F?“.

If no, the heat is driving these symptoms. In that case it’s not time to change a whole lot of variables. Misting, changing the pH of the watering water etc are safe bets. Using the products @Glaucus mentioned or vinegar can help, especially if mixed in batches just before watering so the temp doesn’t rise..

If yes reaching for other solutions in moderation might work. But it’s tricky to do when the plants are under extreme stress.

The watering shown for the azaleas in Kanuma is typically ok, a bit light for my practice. Recall it’s very hard to over water azaleas in Kanuma medium.

Yet these azaleas do not have moss on top and this is exacerbating the water loss. Get some Yamagoke, soak it for a couple hours and tuck it in to the edge of the pot and continue tucking into the media until the surface is completely covered for at least the azaleas.

imho in regard to the pH being high, it’s likely a contributing factor, yet the azaleas in the top two photos do not show a marked chlorosis, which one would see when high pH starts to micronutrient absorption. The last two images above, especially the rightmost, do show some starting. Yet these plants do not have much foliar mass compared to the top two…. and the heat is slowing down the photosynthesis for these plants may be causing it.

For water the best solution is getting an ro system. Changing to an acid fertilizer like Miracid will help once the temps recede below 92ish, but having any chemical fertilizer at high temps is asking for root damage. I’d even pull off the Biogold.

Anyways just some thoughts.

Cheers
DSD sends
 
Did you ever see any new fresh shoots droop/go limp/lose turgor pressure? Because this season I had a bunch of satsuki myself that somehow missed watering, and they go limp, but they didn't get their tips burned on those.
If their new fresh growth never went limp, but the tips are burned, then maybe it is the mineral content in the water after all? Older more lignified growth may not go limp but still get dehydrated.
It is just nice that the plant gives you a warning sign when it does have the tender new growth.
I've only seen my Kikusui go limp once, about a week after I slip potted it into a larger clay pot. I gave it a good watering and it perked back up no problem. Nothing else has ever lost turgidity on me which makes me believe if anything these are getting too much water. I had a few satsukis last year that I definitely killed by over watering them so I always try to be more cognizant of not giving them too much.

The Green Glow was one of the few plants that got a relatively hard cut back, but it's also the one that has had the most new growth on it.

(Also the plan is definitely to call Nuccio's and see if they have any ideas, I'll just have to call them during the week when they are open.)
 
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