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