Weak Satsuki Cuttings

[SgtPilko]

Hey all, I've been striking cuttings regularly when pruning my Satsukis (Nikko, Zuiun in particular) and almost all root, however over time approx half of them start to get weak and I am not sure why. They progress past the very early stages OK, but then later foliage gets dull, discoloured, tiny and some shoots go 'blind' and die off. The others thrive in similar conditions. Any ideas?

Here are a couple of examples:

 

[Glaucus]

Do you mean they get through the first winter and then grow poorly?

I often get better result growing from seed than from cuttings. About 20 to 30% of cuttings that root don't do well the first growing season. They need a repot into nice fresh potting mix to resolve and finally become healthy.
For me, this may be because overpotting and them staying too wet.
The rooted cuttings may also die the first winter. It was -10C here last night and I should kinda have moved my cuttings from the polytunnel (mostly rain shelter) to the unheated shed. Fingers crossed.

So with more details, it is a bit hard for me to judge.
There's some bad cases of rooted cuttings:



It helps to start off with long shoots from healthy plants.
Nikko probably is a variety more challenging to root.

You can also try using air layers. Put a pot around a branch. Consider even burying the whole thing, if it is a low branch and there is enough flexibility to achieve that.
Of course that does not work for recycling stuff you prune off for bonsai purposes.
But this can work better for slow growing varieties. Especially in climates where they grow less (short dry summers).

Once a small plant gets discoloured, it may take a year to resolve.
One thing I still have to try on this is foliar feeding. If the roots are really not able to supply nutrients to the plant maybe foliar feeding can resolve it.

 

[Jetson1950]

Definitely not the expert here, but azaleas like a low PH around 4.5-5.5. Does your potting mix contain kanuma or anything else to keep the PH acidic. If it’s not acidic enough they can’t absorb nutrients very well and won’t thrive.

 

[Glaucus]

Oh, you added pictures.
They look much older than I imagined when you said 'rooted cuttings'. Are you sure this is not pest damage? It kind of looks like it was mulched on, and now is growing back.
They don't look fully dormant. Have they been outside? I would be careful giving them the full winter cold right now.
I think you had similar lows in the UK.

I would say this is not a nutrient issue. Something just too out the growth tips for some reason.

 

[River's Edge]

Hey all, I've been striking cuttings regularly when pruning my Satsukis (Nikko, Zuiun in particular) and almost all root, however over time approx half of them start to get weak and I am not sure why. They progress past the very early stages OK, but then later foliage gets dull, discoloured, tiny and some shoots go 'blind' and die off. The others thrive in similar conditions. Any ideas?

Here are a couple of examples:

View attachment 625683View attachment 625684

The first picture appears to show the effects of pruning back for interior growth as well as staying too wet and or experiencing chilling on the new weaker growth.
The second picture seems to show the effects of cooler temperatures and staying a bit too wet. Although overall in reasonable condition.
Additional information with respect to recent temperature swings, location and daily care routine changes. For example have you adapted your watering practices sufficiently for the time of year and slower growth cycle?
Was the pruning to clean up a problem or a developmental step?
Some thoughts to consider.

 

[SgtPilko]

Do you mean they get through the first winter and then grow poorly?

I often get better result growing from seed than from cuttings. About 20 to 30% of cuttings that root don't do well the first growing season. They need a repot into nice fresh potting mix to resolve and finally become healthy.
For me, this may be because overpotting and them staying too wet.
The rooted cuttings may also die the first winter. It was -10C here last night and I should kinda have moved my cuttings from the polytunnel (mostly rain shelter) to the unheated shed. Fingers crossed.

So with more details, it is a bit hard for me to judge.
There's some bad cases of rooted cuttings:
View attachment 625685
View attachment 625686

It helps to start off with long shoots from healthy plants.
Nikko probably is a variety more challenging to root.

You can also try using air layers. Put a pot around a branch. Consider even burying the whole thing, if it is a low branch and there is enough flexibility to achieve that.
Of course that does not work for recycling stuff you prune off for bonsai purposes.
But this can work better for slow growing varieties. Especially in climates where they grow less (short dry summers).

Once a small plant gets discoloured, it may take a year to resolve.
One thing I still have to try on this is foliar feeding. If the roots are really not able to supply nutrients to the plant maybe foliar feeding can resolve it.

Thanks Glaucus, you're exactly right, they did fine and its the second year that they are struggling. They were probably overpotted to begin with. Good to hear you've seen similar. I will try a good repot in spring and see if that sorts it out. Here in London we've technically gone as low as -4/-5 but only briefly and my urban garden is usually a degree or two warmer than that.

 

[SgtPilko]

Definitely not the expert here, but azaleas like a low PH around 4.5-5.5. Does your potting mix contain kanuma or anything else to keep the PH acidic. If it’s not acidic enough they can’t absorb nutrients very well and won’t thrive.

Yeah its mostly kanuma with a few other random substrates in there depending what i have to hand. Our tap water is alkaline but outside of summer it is mostly the rain doing the watering tbh!

 

[SgtPilko]

The first picture appears to show the effects of pruning back for interior growth as well as staying too wet and or experiencing chilling on the new weaker growth.
The second picture seems to show the effects of cooler temperatures and staying a bit too wet. Although overall in reasonable condition.
Additional information with respect to recent temperature swings, location and daily care routine changes. For example have you adapted your watering practices sufficiently for the time of year and slower growth cycle?
Was the pruning to clean up a problem or a developmental step?
Some thoughts to consider.

Thanks for your response! Its winter here in the South East UK so has swung between 10c and -3c, but only v rarely below freezing. My larger Satsuki have only just dropped their summer leaves. Also these young plants have struggled most of the year not just recently.

You might be right that they are staying too wet - despite being quite free draining the climate here means it stays damp - essentially almost no watering during this autumn-winter period. They essentially have had no care at all for a few weeks I can't even remember the last time i watered these. I might try and keep them under plastic for a while to help with humidity and temperatures.

 

[SgtPilko]

Oh, you added pictures.
They look much older than I imagined when you said 'rooted cuttings'. Are you sure this is not pest damage? It kind of looks like it was mulched on, and now is growing back.
They don't look fully dormant. Have they been outside? I would be careful giving them the full winter cold right now.
I think you had similar lows in the UK.

I would say this is not a nutrient issue. Something just too out the growth tips for some reason.

Thanks Glaucus, these are past the new cuttings stage, i'd estimate 2ish yrs old probably? I've had some minor pest issues with the satsukis, some small caterpillars that roll up in the leaves and eats some foliage, not tons though. I'll try a pest control for those in spring.

These are fully outside, some nights hit freezing but my garden is quite sheltered, I've had frozen pots (only some pots not all) in the morning only about 3 times. Where I live in London is mild, my large satsukis only just went dormant and dropped their summer leaves. This week is going to be 10c and rainy.

 

[Deep Sea Diver]

Concur with most of the above recommendations. These plants are at least 3-4 5 years old from the branching. So not cuttings anymore. For example here is a 5 yoa azalea Sachi no Hana, which is in the same Kozan - Nikko family -



Also both cultivars are Northern cultivars, so perfect for a cooler climate. However these also are a bit finicky during the important summer growth months and improper media/ watering/ water quality/too much sun can cause serious growth issues.

These plants major issue seems to be too much water in the media. Secondarily some pruning technique issues… (aside…it looks like the benefits of a Kanuma media open pores, fast draining were compromised by the addition of other media.). Tip growth issues with azaleas are almost always related to root health/water quality. Secondary would be freezing which is reported not an issue.

Whatever one uses, peat/perlite media or kanuma/pumice media seem to work the best for early years at least for us. These are both well draining acidic mixes.

That said, Alexander Kennedy, who wrote a pretty darn good book on Satsuki azaleas, is from the UK and recommends a peat based grow media for the early years of azalea growth in the UK. Jim Nuccio recommended the same and was more specific, recommending a 2/3 peat (rough if possible) to1/3 perlite mix for the first 4 years.

Would carefully rootwash these plants in late winter when repotting. Pot in a quality media and a tokoname training pot. Then do what it takes to fix the watering/ water quality issue next summer.

Cheers and Good Luck!
DSD sends

 

[Glaucus]

This is what my Hi no Maru and Nyohozan cuttings look like.
Both are also Kozan sports.
Note, the snow just melted away this morning and just before that it was a -11C (12F), which is about as low as it usually gets once every 3 years.
They are sheltered though and near a house.

Nyohozan:


Hi no Maru:


They actually look quite a bit different for what is supposed to be a sport of the same plant.
I assume I didn't mislabel. And it looks close enough. Maybe @Deep Sea Diver can comment. Hi no Maru seems to have larger and rounder leaves.
And Nyohozan as stripes on the flower buds.

I feel both could have shedded more leaves to adapt to the cold.
Not sure why that is. I hope it means good health. I have definitely seem these types azaleas with only the leaves around the flower buds.


One thing I would check is the containers you use. You really want a pot that has a lot of drainage holes and a heel/multilevel foot (forgot the technical term).
Some easy to produce plants come in the cheapest thermofold pots that have a smaller number of drainage hole and a level bottom.
The pot you use can have a big effect. I have some smaller pots that have just 4 holes in the bottom. And they are consistently wetter, less roots, less growth, than the other pots I use.
So if the health is not optimal, try putting it in a new pot, with more holes, and with fresh potting mix. Just throw out all the potting mix that had no roots in it, take the root part, and put it in a new pot.
When cuttings are wet, even if they are overpotted in the new potting mix, they suddenly will do much better.
This will fix stuff like chlorosis. But I don't believe that is what you have.
It could also be your fragile tips died of draught after you pruned?
At this time of year, you want to see a prominent flower bud at almost every terminal bud.

 

[SgtPilko]

Concur with most of the above recommendations. These plants are at least 3-4 5 years old from the branching. So not cuttings anymore. For example here is a 5 yoa azalea Sachi no Hana, which is in the same Kozan - Nikko family -

View attachment 625748

Also both cultivars are Northern cultivars, so perfect for a cooler climate. However these also are a bit finicky during the important summer growth months and improper media/ watering/ water quality/too much sun can cause serious growth issues.

These plants major issue seems to be too much water in the media. Secondarily some pruning technique issues… (aside…it looks like the benefits of a Kanuma media open pores, fast draining were compromised by the addition of other media.). Tip growth issues with azaleas are almost always related to root health/water quality. Secondary would be freezing which is reported not an issue.

Whatever one uses, peat/perlite media or kanuma/pumice media seem to work the best for early years at least for us. These are both well draining acidic mixes.

That said, Alexander Kennedy, who wrote a pretty darn good book on Satsuki azaleas, is from the UK and recommends a peat based grow media for the early years of azalea growth in the UK. Jim Nuccio recommended the same and was more specific, recommending a 2/3 peat (rough if possible) to1/3 perlite mix for the first 4 years.

Would carefully rootwash these plants in late winter when repotting. Pot in a quality media and a tokoname training pot. Then do what it takes to fix the watering/ water quality issue next summer.

Cheers and Good Luck!
DSD sends

Thanks DSD, mine should be max around 3yrs old as I didn't have satsuki azaleas until late 2022 and probably didn't take cuttings immediately.

I haven't really pruned these much except to remove the worst bits that were wizening off and going bad. I'll definitely give them a bit more care and attention this year including a repot into better subtrate, pot etc. I'll go kanuma with better drainage, peat feels too retentive for my location and its so unsustainable it's actually quite hard to buy now (probably with good reason)

Cheers!

 

[SgtPilko]

This is what my Hi no Maru and Nyohozan cuttings look like.
Both are also Kozan sports.
Note, the snow just melted away this morning and just before that it was a -11C (12F), which is about as low as it usually gets once every 3 years.
They are sheltered though and near a house.

Nyohozan:
View attachment 625759

Hi no Maru:
View attachment 625760

They actually look quite a bit different for what is supposed to be a sport of the same plant.
I assume I didn't mislabel. And it looks close enough. Maybe @Deep Sea Diver can comment. Hi no Maru seems to have larger and rounder leaves.
And Nyohozan as stripes on the flower buds.

I feel both could have shedded more leaves to adapt to the cold.
Not sure why that is. I hope it means good health. I have definitely seem these types azaleas with only the leaves around the flower buds.


One thing I would check is the containers you use. You really want a pot that has a lot of drainage holes and a heel/multilevel foot (forgot the technical term).
Some easy to produce plants come in the cheapest thermofold pots that have a smaller number of drainage hole and a level bottom.
The pot you use can have a big effect. I have some smaller pots that have just 4 holes in the bottom. And they are consistently wetter, less roots, less growth, than the other pots I use.
So if the health is not optimal, try putting it in a new pot, with more holes, and with fresh potting mix. Just throw out all the potting mix that had no roots in it, take the root part, and put it in a new pot.
When cuttings are wet, even if they are overpotted in the new potting mix, they suddenly will do much better.
This will fix stuff like chlorosis. But I don't believe that is what you have.
It could also be your fragile tips died of draught after you pruned?
At this time of year, you want to see a prominent flower bud at almost every terminal bud.

My trees don't shed too much as well, possibly as a result of our warm wet winters here in the city. Do you remove excess leaves in Autumn maintenance a la Rick Garcia's book? Presumably just on mature trees? (I have tried to since i learned it)

Will sort that substrate and drainage late winter!

Cheers

 

[Glaucus]

I don't have specimen bonsai trees that I want to look displayable. So I don't even think about it. And even for show trees, removing the leaves that are about to fall manually doesn't make too much sense.
Yes, they will fall on top of the potting mix. But guess what, that's how almost all plants grow; with their own leaves sitting nearby on the soil.
For rhododendron this can often be important because they struggle to take up nutrients like manganese and iron from the soil. So they get them back from the leaves instead.
The argument that deal leaves result in fungus that will then attack living leaves is generally incorrect. Microbes that specialize in eating dead tissues often don't eat living tissues, and vise versa.
That's not a medical principle for human diseases and those with impaired immune systems. But it does make sense in the scenario where you want to decide if decaying organic matter is a source of disease.

The second season can be to let more light and air into the interior. Yes, you don't want weaker buds to be shaded out all winter. But if you have weak buds, and those buds have spring leaves that don't shed, you actually want those leaves to stay on and maybe photosynthesize a bit throughout winter, until spring comes, photosynthesis some more as the new shoots are growing, and then drop off.
Also, when a plant sheds their own leaves, they first take out what they need and feed it back into the plant. If you prune off leaves, you lose all that.

The argument for removing leaves is purely aesthetic. You want the surface of the pot to look superclean. You want to do work on your specimen show tree, and go through every leaf and decide to keep it or remove.
And then the final result is a clean and neat tree.

Kanuma is better for developing nebari because when you repot it is easy to see the roots, remove some kanuma, and repot. With peat you get more patting.
Peat-free potting mixtures are likely similar. For growing out cuttings into small plants, I prefer to use peat with perlite.
You can go for 100% kanuma. But then you need to be a lot more on top of your watering and fertilizer.
For me, peat is just easy-mode. And coco coir or composted pine bark should work similarly. But look out for stuff that is fluffy and coarse. You don't want black dust that when wet you can easily knead.
But that's why I use a lot of perlite as well.