Kiwi’s AZALEA ‘Komo Kulshan’

[KiwiPlantGuy]

Hi all,
I thought I would start a thread on my favourite Kurume Azalea. She flowers without fail (yet) in the first week of November. Our Spring is racing away to Summer now.
She started her journey as a nursery purchase in the Autumn of 2018. I didn’t take a photo after I got this home as I didn’t think it was necessary until now some 5 years later!! For the last 2 photos a year apart I am trying/learning how to balance the growth, but now looks underwhelming, maybe me being critical etc.
So without any more words, I show you her progression from then to now.




I missed out taking a photo in 2021, for obvious reasons.
I have cut a lot of roots to shrink it down to a bonsai pot, so I am hoping for vaguely decent growth this Summer.
Questions for @Deep Sea Diver, and @Glaucus , and @Pitoon,
Is my addition of Scoria to my bark and Pumice mix a bad thing regarding the pH of both Scoria and Pumice?
The lacklustre growth I am wondering. I can now buy Akadama which is huge, So what do you guys think?
Charles.

 

[Deep Sea Diver]

Very nice!

Wondering about your comment of lackluster performance. Can you please expand on this? Hard to tell as I’m not sure of the care and bonsai work the tee has undergone. Amount of bloom? Color of bloom? Foliage etc?

I have a little Komo Kulshan growing out. It took a beating in storage last winter and pruning has made it look like a Charlie Brown tree for now. . Looking forward

First thought is scoria wouldn’t have a lot of added value, other then weight. Water holding is minimal. Presently the big pH influencer likely is your bark.

Some larger akadama in your mix instead of scoria would be an improvement.

Second thought and I don’t want to provoke a ‘pot fight’ is the tree would do better in a deeper pot. Shallower pots look nice, yet an azalea does best in a deeper pot.

Cheers
DSD sends

 

[Glaucus]

I don't see an issue with using something like scoria. Not sure if akadama actually has advantages. I kinda like the (old?) Walter Pall idea that when you use substrate, what it is doesn't matter that much.
He even made the funny point that you could grow bonsai in a bunch of teeth.

Going into specifics, roots may grow into the scoria, because it has pores? It does with kanuma, of course. But kanuma breaks down, which is why you repot. And then you can get the broken up kanuma a bit easier from within the root ball.
Scoria is said to be very hard and durable, so you can't really get it out of the roots when you repot. So then you likely want to repot less often?
Maybe an issue is having very hard and very soft materials in your potting mix. Just a thought.

Akadama drains quicker than kanuma. Is scoria in between them? Just akadama dries too quick for azalea, I would say.
The smaller you make a pot, the more often you need to water. And the more crucial it is to have good drainage, so that the drainage of the substrate and the frequent watering make sure the bonsai always has both air and water.
If you make the pot bigger, you can include soil and water less frequent. With a small pot and good drainage, you may need to water 2 to 4 times a day during the hottest days of summer.

Akadama is also acidic, I believe. I think the reason kanuma is preferred over akadama is not because kanuma is more acidic, but because kanuma retains more water. Kanuma can provide both water and air at the same time.

I have my best results of nonbonsai azalea in peat and perlite, though. For me, cuttings and small plants in 100% kanuma do not do better than the ones in peat/perlite.
But for a smallower bonsai pot and a more mature bonsai, they likely would.

 

[Deep Sea Diver]

Just to set the record straight. Scoria is usually called lava or grit in the US. The scoria here is black, brown, red and various shades in between. It has only a little water retention compared to akadama, kanuma or pumice. That’s because of the tougher non absorbing walls between vesicles in lava, due to a much higher iron component compared to Pumice. Roots will have little penetration except at the surface.

Changing the scoria out vs Akadama will increase the water retention, add a higher CEC component (although the bark will be highest) and allow much more root penetration vs scoria. As your winters are fairly mild, akadama breakdown is likely not a big issue given repotting is done on a reasonable schedule.

We actually recycle media components and one would be very surprised how much akadama isn’t broken down given the freeze thaw we have. Below find a photo of media we recycled from a couple trees in a pot for over four years.

Note the multi colors of scoria, pumice, akadama and even what looks like a bit of quartz!



Cheers
DSD sends

 

[Ugo]

Hi!

Looking at the azalea roots system, the roots wont be able to get into scoria and break it.
Water retention is not optimal but a mix of 1/3 scoria (small size particles) + 2/3 Kanuma could make sense.
I never tried it myself but just in terms of water retention and oxygen between particles it will work, will it be better that I dont know.
My "issue" with kanuma is dust...
I sift it, clean it, sift it again, clean it and I still have dust.. maybe small scoria particles could "help" in term of oxygen available in the mix atleast for the few weeks the substrate needs to be "clean" of dust.
This is theorical but it could worth a try!

 

[KiwiPlantGuy]

Very nice!

Wondering about your comment of lackluster performance. Can you please expand on this? Hard to tell as I’m not sure of the care and bonsai work the tee has undergone. Amount of bloom? Color of bloom? Foliage etc?

I have a little Komo Kulshan growing out. It took a beating in storage last winter and pruning has made it look like a Charlie Brown tree for now. . Looking forward

First thought is scoria wouldn’t have a lot of added value, other then weight. Water holding is minimal. Presently the big pH influencer likely is your bark.

Some larger akadama in your mix instead of scoria would be an improvement.

Second thought and I don’t want to provoke a ‘pot fight’ is the tree would do better in a deeper pot. Shallower pots look nice, yet an azalea does best in a deeper pot.

Cheers
DSD sends

Hi,
So based on the growth patterns of the bush/tree, it was really vigorous in the first 2 years and my growing mix was way different - Pumice, Zeolite, Bark, with a good 50% plus of bark. This leads me to think that this cultivar needs things really acidic. Eg. The lesser % I have gone with bark, the worse the vigour. And the leaves after the flush of growth are not shiny. Just my analysis. Root system seems strong and flowering has always been amazing, but I fear she doesn’t like getting old .
@Ugo - Re Akadama and Scoria (no access to Kanuma, small country etc), I don’t know as I haven’t tried Akadama, but might try next repotting.
Also this Azalea has only been in this bonsai pot for a few months, and for the last 2 years it’s soil mix has been Scoria, Pumice, Bark sifted to between 2-5mm. So I might go back to more bark even 50/50 with Pumice and/or 10% Zeolite as this mineral has amazing nutrient holding properties. But will I risk having too much water holding properties with that much bark? I don’t know.

Anyway, my musings for now, and time to watch the new growth, and wonder about getting some Iron sulphate/Sequestren?
Charles

 

[KiwiPlantGuy]

I don't see an issue with using something like scoria. Not sure if akadama actually has advantages. I kinda like the (old?) Walter Pall idea that when you use substrate, what it is doesn't matter that much.
He even made the funny point that you could grow bonsai in a bunch of teeth.

Going into specifics, roots may grow into the scoria, because it has pores? It does with kanuma, of course. But kanuma breaks down, which is why you repot. And then you can get the broken up kanuma a bit easier from within the root ball.
Scoria is said to be very hard and durable, so you can't really get it out of the roots when you repot. So then you likely want to repot less often?
Maybe an issue is having very hard and very soft materials in your potting mix. Just a thought.

Akadama drains quicker than kanuma. Is scoria in between them? Just akadama dries too quick for azalea, I would say.
The smaller you make a pot, the more often you need to water. And the more crucial it is to have good drainage, so that the drainage of the substrate and the frequent watering make sure the bonsai always has both air and water.
If you make the pot bigger, you can include soil and water less frequent. With a small pot and good drainage, you may need to water 2 to 4 times a day during the hottest days of summer.

Akadama is also acidic, I believe. I think the reason kanuma is preferred over akadama is not because kanuma is more acidic, but because kanuma retains more water. Kanuma can provide both water and air at the same time.

I have my best results of nonbonsai azalea in peat and perlite, though. For me, cuttings and small plants in 100% kanuma do not do better than the ones in peat/perlite.
But for a smallower bonsai pot and a more mature bonsai, they likely would.

Hi,
I am probably with you on the point of using Akadama. Perlite/Zeolite is my options. Anyway, most of my analysis is with the post for @Deep Sea Diver.
Thank for joining the thread and your input.
Charles

 

[Deep Sea Diver]

Thinking about this new information I have a couple thoughts.

it seems likely flowering out each year is slowly draining the trees energy

Also new media isn’t ‘holding’ on to the nutrients in the fertilizer like bark does. Bark has a very high capacity to hold on to and give off nutrients. So the bark would be helping supply nutrients to the tree better, providing resources to keep the tree healthy despite many blooming years. (Guessing the fert includes micronutrients?)

Finally it’s possible after these years the tree needs to start being pushed back to grow new branch’s… as these new regrowing every 3-5 years to keep the water/sugar pathways fully open. Thinking you are already on top of that though

Anyways, it’s a beautiful cultivar and I’m looking forward to seeing more in the future.

cheers
DSD sends

 

[a1dusty]

I don't see an issue with using something like scoria. Not sure if akadama actually has advantages. I kinda like the (old?) Walter Pall idea that when you use substrate, what it is doesn't matter that much.
He even made the funny point that you could grow bonsai in a bunch of teeth.

Going into specifics, roots may grow into the scoria, because it has pores? It does with kanuma, of course. But kanuma breaks down, which is why you repot. And then you can get the broken up kanuma a bit easier from within the root ball.
Scoria is said to be very hard and durable, so you can't really get it out of the roots when you repot. So then you likely want to repot less often?
Maybe an issue is having very hard and very soft materials in your potting mix. Just a thought.

Akadama drains quicker than kanuma. Is scoria in between them? Just akadama dries too quick for azalea, I would say.
The smaller you make a pot, the more often you need to water. And the more crucial it is to have good drainage, so that the drainage of the substrate and the frequent watering make sure the bonsai always has both air and water.
If you make the pot bigger, you can include soil and water less frequent. With a small pot and good drainage, you may need to water 2 to 4 times a day during the hottest days of summer.

Akadama is also acidic, I believe. I think the reason kanuma is preferred over akadama is not because kanuma is more acidic, but because kanuma retains more water. Kanuma can provide both water and air at the same time.

I have my best results of nonbonsai azalea in peat and perlite, though. For me, cuttings and small plants in 100% kanuma do not do better than the ones in peat/perlite.
But for a smallower bonsai pot and a more mature bonsai, they likely would.

I have found kanuma the best for azaleas , had no problem with it breaking down , that’s reporting every to yrs , also if you live in hard water areas you know the kanuma will drop the ph of the water whenever it’s watered , also plenty of air can get through , akadama on the other hand I have found it turns into clay in no time , that’s good for some but not all trees , kanuma would definitely be my way forward

 

[Glaucus]

I got an evaluation document of several evergreen azalea cultivars from a German horticulture site and testing ground. And for like half the cultivars being evaluated, it had the comment 'beginnt zu vergreisen' or 'stark vergreist'.
Which means the planted started to look aged. I assume sights of weak branches or branches lacking vigorous new growth. I never had seen someone comment on this before.
But it is definitely a thing. Especially if you have top notch plants for a nursery vs plants who have been in a garden for 10+ years.
I haven't heard about the xylum and phloem/live vein regrowing.
So for older bonsai, keeping them looking vigorously is definitely an issue.

To me, it manly seemed a thing about uneven growth together with the amount of growth potential spread out too thin over too many ramified branches.
For garden plants, the roots becoming too compacted can also be what limits new growth. Which is why decade old azaleas should at some point be lifted to rejuvenate them.
But with bonsai, we automatically do that.

As for the soil mixture, 2 months seems a bit too early to judge if it is working out for this individual bonsai.
But it does sound like akadama would be a better medium than scoria for being able to reduce the percentage of pine bark.
Perlite retains very little water, despite being very porous. It should be used to improve drainage when one is using soil or a lot of organic material.

Kanuma does turn into dust eventuallly. But it is pretty durable. I noticed that last year in Kanuma city, they had 15C days followed by -8C nights in early spring for like several weeks. Severe temperature swings, I would say.
If freezing and thawing is the main driver of kanuma decomposition, then in Kanuma city, it taked 3 to 4 years for the kanuma to fall apart.
I can imagine that on the Isle of Wight, you don't have those swings at all. And if freezing is the main driver, kanuma should last way longer. And a repot shouldn't be required as often.

 

[a1dusty]

No it’s not so cold on Isle of Wight , have grown many azaleas in kanuma , all my potted azaleas are in kanuma and 30% ish in my pines , never have I seen go to dust , but like you say , not so cold here and I repot every two yrs the ones I not growing on , akadama goes to a clay , my pines like it , other plants might not like the compactnus of the root system as my pines do , does the akadama you all use go to clay or does it stay as granular

 

[Deep Sea Diver]

Imho, it depends on the quality I.e., hardness of the product. It varies a lot depending on the brand. Some is very long lasting, other lots, not so much.
cheers
DSD sends