I’m finding horrible amounts of root rot as I’m repotting this year - maples mainly so far but junipers too. I’m switching to a better draining mix and will probably have to do EVERY tree as a result but I wonder if it’s partly due to the record amounts of rain and if it’s affected anyone else’s trees in this part of the world?
Uk rainfall / root rot
- Thread starter keri-wms
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Shibui
Imperial Masterpiece
Sometimes it is possible to match care to the potting mix you use but when you cannot control the rainfall matching the mix to the conditions makes far more sense. i switched to a very open mix many years ago. i need to water more often and consistently but root problems are far less.
Unfortunately I do not have experience of record rainfall. We seem to be getting the opposite - record high temps and less rainfall.
Unfortunately I do not have experience of record rainfall. We seem to be getting the opposite - record high temps and less rainfall.
AlainK
Imperial Masterpiece
I live in central France, in the Loire valley, and we've had a very, very wet end of winter, with a lot of wind on top of that. 90 km/hr two days ago for instance and very, very heavy showers of rain (but no hail so far, phewww...)
And so far, none of my trees have suffered root rot or any other problem of that kind.
Perhaps it's due to your soil mix.
Here, that's what I use. Of course, quantities can vary, but basically it's :
- 45% Pozzolane
- 25% Akadama
- 15% Pumice
- 15% composted pine bark
All in all, 85% non-organic + 15% organic.
And so far, none of my trees have suffered root rot or any other problem of that kind.
Perhaps it's due to your soil mix.
Here, that's what I use. Of course, quantities can vary, but basically it's :
- 45% Pozzolane
- 25% Akadama
- 15% Pumice
- 15% composted pine bark
All in all, 85% non-organic + 15% organic.
Yeah we seem to be getting one storm a week at the moment! I WAS using bark (or large lumps from basic compost) and molar clay in various ratios, but I’m now trying:
2pt Molar clay (cat litter)
2pt Bark (no fines, nothing soft)
2pt Perlite (or pumice if I can get it)
1pt Akadama (or Kanuma)
...safe to say I’ll be watering more in summer!
2pt Molar clay (cat litter)
2pt Bark (no fines, nothing soft)
2pt Perlite (or pumice if I can get it)
1pt Akadama (or Kanuma)
...safe to say I’ll be watering more in summer!
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AlainK
Imperial Masterpiece
If you can find some where you live, you should try pozzolane, 40/60 % of your mix.
I don't know, but I think most of the components you use retain a lot of water. If you live in a rather "wet" area (like frinstance S-E England) maybe a much more draining soil would help....
I don't know, but I think most of the components you use retain a lot of water. If you live in a rather "wet" area (like frinstance S-E England) maybe a much more draining soil would help....
My understanding is that water retention within particles is a good thing, but you need air gaps between them? I could add something like crushed granite....actually it’s high thermal mass might help reduce pot temperature in summer where the other problem is the heatwave trend!
Well surprisingly the JBPs don’t seem bothered, in the more organic 2019 mix but white growing root tips (bear in mind this hasn’t had time to fill the pot hence straggly roots). Maybe the maples froze?! Also I included the 2019 and 2020 mixes side by side on my hand for comparison...
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Leo in N E Illinois
The Professor
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Sift your soil before use. A more open mix is not created by changing components, it is created by sifting to uniform particle size. Obtain sieves, choose your particle size you want to work with I suggest 6 to 12 millimeters. While the potting media is dry, sift an throw out any particles larger than 12 mm, then re-sift and discard particles smaller than 6 mm. This will give you an open mix, with good air voids. A uniform particle size mix can be watered many times a day and you won't have trouble with root rot, as there will be plenty of oxygen available to the roots.
Sifting with appropriate size sieves is the single best way to improve any bonsai potting media. The exact measurement of the sieve are not as important as eliminating the fines. Nothing magical about 6 to 12 mm. 4 to 7 would work, as would a wide variety of brackets. Finer media, smaller particles are used for smaller pots. More coarse particles are used to larger pots and trees in early phases of development.
Typical set of sieves
stonelantern.com
Sifting with appropriate size sieves is the single best way to improve any bonsai potting media. The exact measurement of the sieve are not as important as eliminating the fines. Nothing magical about 6 to 12 mm. 4 to 7 would work, as would a wide variety of brackets. Finer media, smaller particles are used for smaller pots. More coarse particles are used to larger pots and trees in early phases of development.
Typical set of sieves
Bonsai Soil Sieve Set 3 screens - 11.5" diameter
It's always a good idea to sift the very small particles out of your soil before potting. This helps aeration by keeping your soil cleaner and reducing clogging around the drain holes. You may also want to sift unnecessarily large particles out to create fairly uniform particle size for even...
stonelantern.com
Leo in N E Illinois
The Professor
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Key is the more uniform the particle size, the more air the media will hold.
It doesn't matter the components of the mix, bark, akadama, pumice, turface, pozzolane, expanded shale, perlite, chunks of rubber tires, the component doesn't matter in terms of creating a soil with physical structure needed to support good healthy roots and allow enough air to prevent pathogenic bacteria and fungi. In addition good air penetration favors beneficial mycorrhiza.
You choose your components for their desired chemistry, then sift your components to obtain the desired physical structure. I use bark, pumice & lava, or a similar equivalent mix, varying the amount of bark depending on whether deciduous moisture loving tree or a conifer preferring a dry environment.
It doesn't matter the components of the mix, bark, akadama, pumice, turface, pozzolane, expanded shale, perlite, chunks of rubber tires, the component doesn't matter in terms of creating a soil with physical structure needed to support good healthy roots and allow enough air to prevent pathogenic bacteria and fungi. In addition good air penetration favors beneficial mycorrhiza.
You choose your components for their desired chemistry, then sift your components to obtain the desired physical structure. I use bark, pumice & lava, or a similar equivalent mix, varying the amount of bark depending on whether deciduous moisture loving tree or a conifer preferring a dry environment.
Same again, air layer with rotten roots, this one’s Deshojo. HAD been doing well, roots out the bottom etc! Actually still a pretty open mix in the rootball....this one’s alive nearer the trunk for a change.
Some black sludge at the bottom admittedly due to organic stuff breakdown, 2020 mix won’t have that at least.
Some black sludge at the bottom admittedly due to organic stuff breakdown, 2020 mix won’t have that at least.
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sorce
Nonsense Rascal
Sphagnum left in the roots equals root rot for certain here.
It attracts root rot, and likely ships with spores.
Sorce
sorce
Nonsense Rascal
And when we grate it over our trusty soil screens....
Like fucking morons.
We spread it to every tree.
Resorce.
Sorce
Like fucking morons.
We spread it to every tree.
Resorce.
Sorce
Yeah good call, I’d made a mental note there too - I always used to pick it all out but lots of people seemed to reckon it’s best left to stop the new roots snapping so last year I left it....back to the picking method I reckon!
Shibui
Imperial Masterpiece
It is OK to leave some sphagnum in the roots as long as you can remember it is there and adjust watering to allow for it.
Occasionally I have some issues with fungal infections, mostly with Japanese maples, after a cool wet winter. The black bark at the base of your shishigashira is typical but can spread right round the trunk and effectively ringbark the tree. For me this is usually in pots sitting on the ground. Many recover if found early and the trees put in a more exposed location so they drain better and have better air movement. Fungicide may help if the infection has not spread too far.
I note that, although the roots appear brown, the tips appear to be healthy and white which is a good sign.
Not sure whether my issue is the same as yours but only appears to affect maples here and mostly JM. Hope yours pull through.
Occasionally I have some issues with fungal infections, mostly with Japanese maples, after a cool wet winter. The black bark at the base of your shishigashira is typical but can spread right round the trunk and effectively ringbark the tree. For me this is usually in pots sitting on the ground. Many recover if found early and the trees put in a more exposed location so they drain better and have better air movement. Fungicide may help if the infection has not spread too far.
I note that, although the roots appear brown, the tips appear to be healthy and white which is a good sign.
Not sure whether my issue is the same as yours but only appears to affect maples here and mostly JM. Hope yours pull through.
The pine with white tips appears ok but the white tipped maple roots are dead for sure, I can easily mush them with my fingers leaving the thin bit of wood “thread”.
They were on benches but tooooo much rain / exposure to rain.
The layers with rotten roots have been lightly scraped and everything dead cut back, dabbed with hormone powder and put in pure kanuma, tied up in a clear plastic bag like oversized cuttings.....all I can do is cross my fingers! I reckon they stand a fair chance, seems logical there would be dormant “root buds” / handy patches of callous there to kick things off faster than a normal cutting!
They were on benches but tooooo much rain / exposure to rain.
The layers with rotten roots have been lightly scraped and everything dead cut back, dabbed with hormone powder and put in pure kanuma, tied up in a clear plastic bag like oversized cuttings.....all I can do is cross my fingers! I reckon they stand a fair chance, seems logical there would be dormant “root buds” / handy patches of callous there to kick things off faster than a normal cutting!
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