Azalea Issues

[mandrews93]

Hello! I’ve lost a few azaleas over the past couple months, most likely from root rot/overwatering/poor draining soil. I have these that are showing signs of problems, but I’m not sure if it’s the same issue, since the now dead ones declined much faster with the leaves crisping up after the tips became dark brown. Planning to repot these in kanuma, but curious if anyone can identify any other issues based on the photos. Thanks!

 

[Glaucus]

Too much sun and just overal too hot? More like chronic draught and heat than acute.

The orange is sun or heat stress. I don't see a thick layer of moss or even worse liverworts on your potting mix. Instead, I see very dusty dry potting mix.
Probably, you need a 50% shade cloth and to water 1 or 2 times a day. And mist them to keep the shaded area cool to about below 30C on very hot days.

But you don't say what your location is. For most people, it is winter now. And it doesn't look like winter for you.

 

[mandrews93]

Too much sun and just overal too hot? More like chronic draught and heat than acute.

The orange is sun or heat stress. I don't see a thick layer of moss or even worse liverworts on your potting mix. Instead, I see very dusty dry potting mix.
Probably, you need a 50% shade cloth and to water 1 or 2 times a day. And mist them to keep the shaded area cool to about below 30C on very hot days.

But you don't say what your location is. For most people, it is winter now. And it doesn't look like winter for you.

Central Coast, California. I just put a top layer of sphagnum peat moss to try and get a little acid into the soil without a full repot. It’s about 60-65F during the day, 40F during the night here right now so it’s not heat.

 

[Gabler]

Frost damage? How hardy are these cultivars?

 

[mandrews93]

Frost damage? How hardy are these cultivars?

Gumpo Pink, Korin, Okusatsuki, Minato. We haven’t been below freezing at all, and my other azaleas have been fine. Issues started showing up in the autumn, when temps wouldn’t drop below 50F

 

[Glaucus]

Using kanuma can make it even harder to manage these. Azaleas in pots in Cali are hard. With substrate rather than soil, even harder.
Rain and cool summers and short somewhat cold winters are ideal.
If you have to water with hard tap water, substrate is also a challenge. You ned to be on top of fertilizing properly, not too little or too much. With soil, you have more buffer space. Both for the acidity. And for excess but safe nutrients in the soil.
Dry strong winds and hot summers are the worst.

No way you have root rot in California. I have just clouds and rain and now it is almost freezing -10C and my azaleas look perfect, no root rot.
They are in peat-perlite.

Not sure if you also had drought and strong dry winds recently, like some parts of Cali that were sadly in the news.

You will get a cm of liverworts on your potting soil, if you overwater, before you get root rot.

Kanuma is good. But maybe in California, that's living on the edge. Even Central Cal. Won't say it can't be done, but surely it won't e easy mode.

 

[Gabler]

You will get a cm of liverworts on your potting soil, if you overwater, before you get root rot.

I think that's a European thing. I've never seen liverwort in my life.

 

[Glaucus]

Oh, they occur everywhere. Even some parts of Antarctica. Just not on the moon. But if they are a common plant pest for potted plants, triggered by overwatering, probably not.
I doubt you get them in Cali. There is nothing on the top of his soils. So that does not indicate overwatering to me.

 

[mandrews93]

Oh, they occur everywhere. Even some parts of Antarctica. Just not on the moon. But if they are a common plant pest for potted plants, triggered by overwatering, probably not.
I doubt you get them in Cali. There is nothing on the top of his soils. So that does not indicate overwatering to me.

The ones that died already were more shaded than these ones - definitely wasn’t following good watering practices - soil got muddy at bottom, top wasn’t drying and grew moss, leaf tips turned brown from the top down, eventually crisping up.

 

[Esolin]

No expert, but you can definitely over water azaleas in So Cal. They like moist but airy soil, not water-logged soil. Pretty sure I've killed a few with overwatering. Commercial growers here keep them under shade cloth because heat can certainly be an issue, and I think it's more an issue for the roots. Hot moist roots cook in pots on warm days. I've had this issue with a few species like cotoneaster, and I think azaleas are also susceptible. Frost damage is also a thing this time of year. Fertilizing can also cause leaf burn. It may be a combination of things. Azaleas are beautiful, but fussy.

 

[Deep Sea Diver]

Gumpo Pink, Korin, Okusatsuki, Minato. We haven’t been below freezing at all, and my other azaleas have been fine. Issues started showing up in the autumn, when temps wouldn’t drop below 50F

We have each of these azalea cultivars. These are all strong growers given decent horticultural practice. Korin would likely be the most susceptible to heat. Right now they look awful beat up.

The images could indicate over watering, underwatering, too much fertilizer, poor water quality, and hard frost.

However from the data given totally agree with your assessment of over watering and poor media. Especially considering the muddy media. However excess sunlight and poor water quality certainly could have contributed, but the latter data isn’t available.

Changing to kanuma is likely the best idea, but what else to add to the mix is a good question. However really hard to overwater an azalea in kanuma. It drains really well, so as @Glaucus indicated, multiple waterings and misting a day may be needed.

With the azaleas beat up state it will be touch and go. Be sure to completely rootwash all the media off the roots and around trunk area before repotting into kanuma. Plant in a deep pot. Keep in filtered shade all day for the first 3-4 weeks or until the plants push new leaves. From then on, ease into shade early morning sun and filtered shade afterwards. Use shade cloth as needed.

My recommendation is for a 6” diameter rootball use a pot at least 2.5” inside depth, for a 9-10” rootball use a 3.5-4” inside depth. Tokoname training pots are excellent choices

Central California is a pretty wide area. The azaleas could be located anywhere from Santa Clara near the coast to toasty Kern County. It’s one of the reasons we ask folks to enter both their approximate location and USDA Plant Hardiness Zone… so we can give excellent advice. When we do not know these data, our advice gets much more generalized

In the past, quite a few of the folks in this general area have indicated the addition of chopped pre wetted NZ Sphagnam moss in their media and use of shade cloth to help their potted plants survive. Not sure the percentage. Contacting your local club’s azalea folks will help pinpoint this information. Would hazard a guess of at least 20% in warmer areas.

Finally, please look up your local water purveyor’s required annual water quality report and check both the carbonate level (to get your water’s hardness level) and pH. If these data aren’t posted please call the water purveyor. These data could indicate the need for a chelating agent and further action to assure the long term health of all your bonsai.

Good luck and Cheers!
DSD sends

 

[Glaucus]

Of course it could have been from overwatering. I see the point of soggy soil just sitting there a bit more now. But hard to see that happen if you do not overwater.
I have an azalea actively growing indoors now. And it is near overpotting. I need to water it every 2 days. If I wait 2.5 days, it starts to wilt.
And that's at 65% humidity in a grow tent under long day grow lights.

So you absolutely need soil that drains well. But you absolutely need to water a lot in California. And I don't see signs of something growing on the top of wet soil.
If you put a bucket of dirt in the shade in California, and you absolutely keep it wet, I am sure stuff will grow on top.

They could definitely have been overwatered at one point. Which likely ailso causes them to be chlorotic. At least, it seems to do in my climate.
And then they have bad roots or even damaged roots. And then later on, the lack of roots gets them to suffer.
That said, I have had some azaleas where grubs at almost all the roots. I dug these up, replanted, and most didn't wilt yet.

What I did see is this:




Which happened to some young azalea plants in a growing field with soil bare of any roots or weeds during a very dry and unusually hot summer, for my climate, where I had to water manually every day.
I never saw this orange colour before, or after.

So since the tips are also burned, plus this orange colour, plus what I hear about hot and dry weather in Cali, that's my conclusion.

People here like to recommend substrate over soil. But I see these plants are not bonsai (yet) and sit in nursery containers.
California would be the first place on my list where you don't want to use 100% kanuma when planting azalea raw material or nursery plants in pots.
Strong dry winds are azalea killers. Especially if they stand in substrate.

 

[mandrews93]

We have each of these azalea cultivars. These are all strong growers given decent horticultural practice. Korin would likely be the most susceptible to heat. Right now they look awful beat up.

The images could indicate over watering, underwatering, too much fertilizer, poor water quality, and hard frost.

However from the data given totally agree with your assessment of over watering and poor media. Especially considering the muddy media. However excess sunlight and poor water quality certainly could have contributed, but the latter data isn’t available.

Changing to kanuma is likely the best idea, but what else to add to the mix is a good question. However really hard to overwater an azalea in kanuma. It drains really well, so as @Glaucus indicated, multiple waterings and misting a day may be needed.

With the azaleas beat up state it will be touch and go. Be sure to completely rootwash all the media off the roots and around trunk area before repotting into kanuma. Plant in a deep pot. Keep in filtered shade all day for the first 3-4 weeks or until the plants push new leaves. From then on, ease into shade early morning sun and filtered shade afterwards. Use shade cloth as needed.

My recommendation is for a 6” diameter rootball use a pot at least 2.5” inside depth, for a 9-10” rootball use a 3.5-4” inside depth. Tokoname training pots are excellent choices

Central California is a pretty wide area. The azaleas could be located anywhere from Santa Clara near the coast to toasty Kern County. It’s one of the reasons we ask folks to enter both their approximate location and USDA Plant Hardiness Zone… so we can give excellent advice. When we do not know these data, our advice gets much more generalized

In the past, quite a few of the folks in this general area have indicated the addition of chopped pre wetted NZ Sphagnam moss in their media and use of shade cloth to help their potted plants survive. Not sure the percentage. Contacting your local club’s azalea folks will help pinpoint this information. Would hazard a guess of at least 20% in warmer areas.

Finally, please look up your local water purveyor’s required annual water quality report and check both the carbonate level (to get your water’s hardness level) and pH. If these data aren’t posted please call the water purveyor. These data could indicate the need for a chelating agent and further action to assure the long term health of all your bonsai.

Good luck and Cheers!
DSD sends

Thanks a lot for that detailed response! I’m in San Luis Obispo, so very close to the coast. I put them in kanuma in unglazed terra cotta azalea pots, so similar to Tokoname pots in a pinch. I’m actually surprised they’ve held on as well as they have, given that they’ve declined over the past couple months. If they don’t survive the repotting, I won’t be too shocked. I didn’t fertilize in the fall into winter as they started showing these issues.

I tried to be careful with the roots and not prune a ton off, but it was tough going - a ton of fine roots and the soil was pretty compacted in there. I figure I would rather have a chance of saving it by getting it into some better substrate than just let it keep going downhill. Will update either way!

 

[Deep Sea Diver]

That’s great! How about shooting some images in 8 weeks as an update?

Be advised terra cotta pots are a poor substitute for Tokoname pots.

The main reasons are the clay is lower fired and thinner so evaporates water very much faster. Secondly the slope is usually either too steep or shallow. So moss the surface completely or, barring this, bark the surface to slow surface evaporation and be sure to water sufficiently to avoid drying out. Misting both foliage and pots helps a bit. Get the better pot and slip into these next year.

Good luck!

DSD sends

 

[mandrews93]

That’s great! How about shooting some images in 8 weeks as an update?

Be advised terra cotta pots are a poor substitute for Tokoname pots.

The main reasons are the clay is lower fired and thinner so evaporates water very much faster. Secondly the slope is usually either too steep or shallow. So moss the surface completely or, barring this, bark the surface to slow surface evaporation and be sure to water sufficiently to avoid drying out. Misting both foliage and pots helps a bit. Get the better pot and slip into these next year.

Good luck!

DSD sends

So…all of my Satsuki azaleas are in kanuma now. My southern indicas are flowering as usual in March. They are all still alive, as are my rooted cuttings. Flower buds forming on some, not on others. The large one I was most concerned with is seemingly recovering. I’ve been applying antifungal to the foliage but may have to cut back and wait for new foliage to emerge without the brown spots. As for the smaller two, they have gotten quite orange but not crispy. Still green under the bark. If they don’t improve in the kanuma, I’m going to just cut them back in May and hope they push new growth.
.

 

[Deep Sea Diver]

These got hit pretty hard. The issue doesn’t manifest as fungal in the images. Would back off the anti fungal, possibly do more harm than good. Damaged foliage of this sort doesn’t get better. So please do not use the present foliage as an indicator.

So believe you are correct, the best hope is to grow out new foliage.

There are a couple ways one could do now, as this is the very best time of the growing year to get a strong response and give the longest time to grow out new growth.

1. Trim each branch back to the innermost green foliage on each branch and remove the flower buds on this growth. This is the action that would happen in our practice. It will spur backbudding, reduce the load on the azalea and divert the energy away from blooming towards vegetative growth. Finally this will be a good step towards actually creating a bonsai azalea.

2. Alternately, remove all flower buds on all the present growth (use two hands).

In each case, removing flower buds spurs the new branchlets to form by removing the azaleas push to bloom… given the azaleas have the energy to do so.

Cheers
DSD sends

 

[mandrews93]

These got hit pretty hard. The issue doesn’t manifest as fungal in the images. Would back off the anti fungal, possibly do more harm than good. Damaged foliage of this sort doesn’t get better. So please do not use the present foliage as an indicator.

So believe you are correct, the best hope is to grow out new foliage.

There are a couple ways one could do now, as this is the very best time of the growing year to get a strong response and give the longest time to grow out new growth.

1. Trim each branch back to the innermost green foliage on each branch and remove the flower buds on this growth. This is the action that would happen in our practice. It will spur backbudding, reduce the load on the azalea and divert the energy away from blooming towards vegetative growth. Finally this will be a good step towards actually creating a bonsai azalea.

2. Alternately, remove all flower buds on all the present growth (use two hands).

In each case, removing flower buds spurs the new branchlets to form by removing the azaleas push to bloom… given the azaleas have the energy to do so.

Cheers
DSD sends

I hard pruned the one on the left in the most recent set of photos. There was only orange foliage. Hoping it pushes new growth, but if it doesn’t, not the end of the world. The other one of the pair i cut back to green. As for the large one, I will need to take a longer look at it this week to better identify where buds are and where I can cut back to.

 

[AAG1887]

I am in Hayward California area. I lost a few azalea last summer as well. With symptoms looks very similar to the photo in first post. Last summer here is indeed very hot.

I am not much of an expert, and new to bonsai and plant in general. I am discovering as I go. Not sure I be able to help you but I'll share my thoughts and observation anyway.

Most of my cultivar is from nuccio, 1 gal size nursery material.
My azalea is on a north east facing patio, so only morning sun really.

Still, I suspect it's the heat and low humidity air is what killed my azalea. And perhaps especially heat to soil and root.

I found a paper from university of Kentucky describing how soil and thus root temperature of potted plant, can regularly go above dangerous level, if the pot is hit by direct sunlight and especially if it's black.

I had a test with my hand a few days ago. And indeed at around 10am, the side of black 1 gal nursery pot is hot to the touch, so perhaps 40-50 C. Actual soil temp may not be as high as sidewall, but it's believable they will be higher than plant can tolerate.

I lost a Korin, a very small Kazan in 4 inch pot. A Kogetsu. A matsu kagami lost half of the branch but held on to life and recovered this year. Strangely a kikisui is completely unharmed despite being in the same location condition as the others.

The difference is the kikushui is a broom style tree (or admittedly I did not find a good trunk line solution and just left it alone), I suspect because of this, it has more foliage and created more shade for itself and it's pot. Thus perhaps stayed cooler. Or maybe it's just a more heat tolerant cultivar.

As a counter measure I wrapper all of my pot in aluminum foil this year, lol. So it reflect sunlight and alien mind control away

How effective it will be? I don't know, we'll see after this summer. But at least now when I touch the foil, it feels cool even in direct sunlight.

I'll probably buy a cheap food thermometer later and do a actual quantitative measure of soil temp with/without foil.

Speaking of the cultivar I lost. I hope to buy them back. I managed to source Kazan and kogetsu again from nuccio before the were hit by fire. But for the life of me I cannot find where to buy Korin again. I got my original korin from Bloom river garden in OR. But looks like they no longer sell that. If you guys know where to get it please do let me know.

Thanks

 

[AAG1887]

I should add the symptom of my azalea did not immediately show in the peak of summer either.
But rather in Sept, Oct. Kind of a slow decline. Which seems to be fitting with the symptom of root damage, and delayed decline. At least according to that paper anyway.

 

[Deep Sea Diver]

Greetings and Welcome Aboard Bonsai Nut!

This is a great write up!

Yes aluminum foil will help. In August 2022 measured the temperature in a 1gal black plastic training pot 1” inside the edge as 106.7F in direct sun with a peat based media. That’s not exactly your situation, but does explain how keeping a plant in training pots during hot summer days can negatively affect the sensitive roots of an azalea.

Also root rot can occur in any pot, but peat media holds moisture way longer than kanuma blends do. Thus plants in peat based media can be easily overwatered, triggering conditions for root rot.

However it’s hard to tell with just this information. To ascertain whether root rot has occurred, the plant needs to be taken out of the pot and the roots examined.

A couple bits of information would help

How long did you have the Nuccio’s azaleas in the 1 gallon containers?

What is your normal watering routine?

Finally, there are some incredibly knowledgeable azalea folks in your local area who can provide you with locally based information.

They are the Bay Area Satsuki Aokokai. They meet at Lakeside Garden Center, Lake Merritt, 666 Bellevue Ave. in Oakland.
Darren Wong is one of the highly respected members. Here is their contact sheet.

Contact Us

Have a question or comment? Please use the contact form below, and we’ll get back to you as soon as possible. We look forward to hearing from you! Officers for 2024: President – Ron Reid – ronreid2…

satsukiazaleabonsai.org

Cheers
DSD sends