Brown spots on azalea leaves

Kalebh

Sapling
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Hi everyone, one of my Satsuki has these brown spots on several of the leaves. I repotted it in early spring (pure kanuma) and gave it a haircut at the beginning of June. I noticed the spots before the haircut, however, since the flush of new growth I have noticed even more spots than before. I water the plant every morning and it gets morning sun untill about 2. Also the roots at the nebari don't look great, I'm not sure why. Last thing to note is I fertalize about every week with the liquid azalea miracle grow. Thanks in advance 👍
 

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NOZZLE HEAD

Shohin
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Looks like a fungal leaf spot disease to me.

Cercospora, Septoria, Phyllosticta, and Colletotrichum are possible culprits.

Any fungicide treatments will just protect new leaves, not remove the spots.

Try to keep the foliage dry.

Where are you located? You can add it to your profile, it helps with stuff like this.
 

Kalebh

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I'm from North Carolina. Thank you for your help, which fungicide is best to treat it with?
 

Deep Sea Diver

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Just 3 thoughts....besides @nozzle_head advice.
None will hurt your azalea...
A. you may want to cut back on the Miracid to every two weeks at half label strength.
B. be sure your soil shows dryness on top before you water it.
C. Cut down the sun to only morning if possible. If you must add sun do the last two hours of the day vs 12-2.
btw: What Satsuki variety is this azalea?
Cheers
DSD sends
 

Shibui

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What is it about the roots that does not look great?
I think it is potted way too high in the pot both for aesthetics and practically - soil will continue to wash away from the roots exposing more fine roots which then dehydrate and die. That does not usually kill the tree because there's almost always enough deeper roots to keep it alive but if most of the fine roots of any of those surface roots die off then so will the larger root.

The picture appears to show very wet. Maybe it has just been watered or had rain? There also appears to be a film of green over the surface which usually indicates excessive moisture. Azaleas do not like to be dry but they equally don't like growing in a bog.

I suspect there are a number of different factors at play with this tree but be a bit careful making lots of huge changes at one time.
 

fredman

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I also think it's to much moisture. That's also the ideal environment for fungal growth. As said above, the soil needs to dry some before the next watering.
Interesting..I saw a video where Paul Eslinger said when Kanuma is kept wet all the time, azaleas get lazy and don't extend their roots much. Also, root rot can occur then. They need to dry out some so they can go seek the moisture. Fine line I know 😁
 

Kalebh

Sapling
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Awesome thanks everyone, I have talked to several people who don't water their larger specimens but every few days. I'm going to cut back on watering it. Also, I agree I planted it too high, at the time I was fairly new I'm bonsai and just wanted to get it in the pot
I'm not sure of the variety it has nice pink flowers though. I'll attach a photo. Thanks again!
 

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JudyB

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Looks like there is a disparity between the old and new soils, and that could be adding to your watering issue if there is one. The old soil is holding more water than the new soil. All I can think of to help right now is to put a chopped sphagnum topdressing over the newer soil, that might help. Next time as you know repotting lower will be good, as azalea like the surface roots to stay moist and cool. Sounds like a lot of chemical fert for an azalea to me, and if you can use rainwater to water with, they do like that as well.
You should go to your profile page and put your location there so it shows up under your name, so people familiar with your climate can help you.
 

Harunobu

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I think I would cover the roots with sphagnum moss, water less, stop fertilizing, put them in shade/dappled sun. They don't look that bad. Of course there are these spots. And the new leaves seem a tiny bit too pale, but not excessive. Not familiar with any fungus that does this, but we don't really have many azalea pests here in Europe (as we have no native azalea species). But if fungus is able to grow on the leaves, they must be too moist? Less moisture, more ventilation? If you know the actual fungus, you could try a fungicide. At this point, I think I wouldn't go for a broad spectrum fungicide (ie copper ions). The paleness of the new leaves could either get worse and turn into actual chlorosis, or just go away. So keep an eye out on that. That's always the main thing to look for when judging azalea health at this time of year; how much new leaves does it have? And how green are they?

It is easier to maintain health if kanuma completely covers all the roots/most of the nebari. If it is not a sunny warm low humidity day, you can let the kanuma dry out. The colour of dry kanuma is different from wet, so it is easy to see when it needs watering. when the surface kanuma starts turning pale/dry, then you kind of know that the core of the roots, where the fine roots are, are still moist. And then you can water again. Potentially, you could even wait half a day, then water. What you don't want is all your kanuma particles to be permanently dark/moist. Or the surface kanuma to be pale/dry while it is sitting in the sun unwatered for the rest of the day. If with the watering you have done recently, you have never seen the pale kanuma, you know you need to water less. But you want the kanuma to go dry on days where not a lot of water evaporates from the leaves. Then you can keep it nice and wet on those hot low humidity days.
If your climate is very continental though, you may not have those low stress days in summer. And if you cover your kanuma with sphangum, you may not be able to see the kanuma, and you are slightly changing the dynamics. If you add sphagnum, the sphagnum should never be dried out.

And when you repot this tree, I would try to get rid of the black much/moss in those upper roots. Personally, I don't like moss growing on top of azalea roots. But I am not 100% sure if they are beneficial or not. Now, you exposed all these roots. But in a normal situation, the moss could help keep the most vulnerable roots moist and cool during summer. But they could also act like a huge sponge, interfering with proper watering. Maybe they are a good thing to have in areas with very dry summers. I don't have a definite thought on this. But when moss starts growing, and often it eventually will, they really change the dynamics of watering and moisture in the top soil.

In Japan, all trees are displayed with moss. But my suspicion is that the day after the display, they immediately remove the moss. Not sure if I vaguely remember hearing this, or if I am just making this up. But besides moss, there seems to be algae growing as well? Definitely seems too wet.
 
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