Late summer repotting

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Yes, and the usefulness of the leaves and sun (to the extent that JM are exposed) for growth of replacement roots.
Isn't that a catch 22? Chopping off half the roots with a full canopy? And exposed to sun? What about transpiration and not enough roots to sustain all the leaves?
 

Walter Pall

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Isn't that a catch 22? Chopping off half the roots with a full canopy? And exposed to sun? What about transpiration and not enough roots to sustain all the leaves?
One of the best things about late summer potting: 'Yo leave the full canopy - do not cut roots and folate at the same time. You can cut roots, but you do not always have to. Don't forget that root cutting is severely weakening a tree. But if you have to and leave the full canopy new roots will grow much quicker than in spring. In spring the tree puts all it's strength into new foliage. If you then cut roots the tree has to make a decision here and divide it' strength. There is no new energy coming from the non-existing mature foliage and the new roots have to be fed from energy that was meant for foliage.



Sure you expose the canopy to full sun after late-summer repotting. Temperatures will go down quickly , days are shorter. The full sun on mature foliage will create energy to get lots of new roots quickly. The evaporation is there, but it's getting better every day.

In my garden the very best time is exactly now. In other gardens it will be one or two weeks or more later or even earlier. You have to figure out yourself.



This is why late summer repotting is the safest, saver than spring repotting. Also when you do root work. This is why I recommend to forget everything you thought you knew.



The full foliage is also important in spring for the same reason. This is why I advocate to pot as late as possible in spring with foliage already out for most trees. The full foliage which is not cut at the same time will send growing hormones to the roots (auxin) with the message 'grow fast everything is OK here I can support much more roots and need them). If you cut foliage the foliage would not send the message and as a s result the tree is not quite sure what to do.



Attached you see late summer (beginning of August) repotting of Japanese maple and trident maple And then spring repotting of Japanese maple. As one can see this is accompanied with heavy root pruning. So the claim that this man is southern Germany only buys top Japanese trees and repots them with no root work is ridiculous and exposes the writer as ignorant. These trees were exposed to full sun and grew happily after that.

These were absolutely not emergency repots. I could have chosen any day of the year. Does someone really think that I do all this just to show off how different my methods are? Would it not make much more sense that I do this with precious trees because it is the best for them.

All this information was written several times already in the past years. So the push to write it again is annoying and shows disrespect of my efforts. If you want something from me you have to do your homework first.


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Palmer67

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One of the best things about late summer potting: 'Yo leave the full canopy - do not cut roots and folate at the same time. You can cut roots, but you do not always have to. Don't forget that root cutting is severely weakening a tree. But if you have to and leave the full canopy new roots will grow much quicker than in spring. In spring the tree puts all it's strength into new foliage. If you then cut roots the tree has to make a decision here and divide it' strength. There is no new energy coming from the non-existing mature foliage and the new roots have to be fed from energy that was meant for foliage.



Sure you expose the canopy to full sun after late-summer repotting. Temperatures will go down quickly , days are shorter. The full sun on mature foliage will create energy to get lots of new roots quickly. The evaporation is there, but it's getting better every day.

In my garden the very best time is exactly now. In other gardens it will be one or two weeks or more later or even earlier. You have to figure out yourself.



This is why late summer repotting is the safest, saver than spring repotting. Also when you do root work. This is why I recommend to forget everything you thought you knew.



The full foliage is also important in spring for the same reason. This is why I advocate to pot as late as possible in spring with foliage already out for most trees. The full foliage which is not cut at the same time will send growing hormones to the roots (auxin) with the message 'grow fast everything is OK here I can support much more roots and need them). If you cut foliage the foliage would not send the message and as a s result the tree is not quite sure what to do.



Attached you see late summer (beginning of August) repotting of Japanese maple and trident maple And then spring repotting of Japanese maple. As one can see this is accompanied with heavy root pruning. So the claim that this man is southern Germany only buys top Japanese trees and repots them with no root work is ridiculous and exposes the writer as ignorant. These trees were exposed to full sun and grew happily after that.

These were absolutely not emergency repots. I could have chosen any day of the year. Does someone really think that I do all this just to show off how different my methods are? Would it not make much more sense that I do this with precious trees because it is the best for them.

All this information was written several times already in the past years. So the push to write it again is annoying and shows disrespect of my efforts. If you want something from me you have to do your homework first.


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This just makes sense and it's very logical. I tried your hedge cutting method for my maples and have seen stellar results. I'm on board with this. Thank you!
 

Maloghurst

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I don't think anyone should, even if they've been "successful".

Late Summer. That is the time.

We musn't fear the heat.

Sorce
I’m sorry I misspoke, I meant late summer as well Thanks for answering my question.
One of the best things about late summer potting: 'Yo leave the full canopy - do not cut roots and folate at the same time. You can cut roots, but you do not always have to. Don't forget that root cutting is severely weakening a tree. But if you have to and leave the full canopy new roots will grow much quicker than in spring. In spring the tree puts all it's strength into new foliage. If you then cut roots the tree has to make a decision here and divide it' strength. There is no new energy coming from the non-existing mature foliage and the new roots have to be fed from energy that was meant for foliage.



Sure you expose the canopy to full sun after late-summer repotting. Temperatures will go down quickly , days are shorter. The full sun on mature foliage will create energy to get lots of new roots quickly. The evaporation is there, but it's getting better every day.

In my garden the very best time is exactly now. In other gardens it will be one or two weeks or more later or even earlier. You have to figure out yourself.



This is why late summer repotting is the safest, saver than spring repotting. Also when you do root work. This is why I recommend to forget everything you thought you knew.



The full foliage is also important in spring for the same reason. This is why I advocate to pot as late as possible in spring with foliage already out for most trees. The full foliage which is not cut at the same time will send growing hormones to the roots (auxin) with the message 'grow fast everything is OK here I can support much more roots and need them). If you cut foliage the foliage would not send the message and as a s result the tree is not quite sure what to do.



Attached you see late summer (beginning of August) repotting of Japanese maple and trident maple And then spring repotting of Japanese maple. As one can see this is accompanied with heavy root pruning. So the claim that this man is southern Germany only buys top Japanese trees and repots them with no root work is ridiculous and exposes the writer as ignorant. These trees were exposed to full sun and grew happily after that.

These were absolutely not emergency repots. I could have chosen any day of the year. Does someone really think that I do all this just to show off how different my methods are? Would it not make much more sense that I do this with precious trees because it is the best for them.

All this information was written several times already in the past years. So the push to write it again is annoying and shows disrespect of my efforts. If you want something from me you have to do your homework first.


View attachment 257343View attachment 257344View attachment 257345
Thank you Walter, Im realizing that all the root studies in the world are good info to know but do not necessarily mean as much when you are dealing with Bonsai.

One last question, do you collect your hornbeam and beech etc in late summer as well? Not technically repotting so just looking for clarification. I’m apologize if this info is covered elsewhere, a simple yes or no will suffice.
Thank you
 
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Walter Pall

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One last question, do you collect your hornbeam and beech etc in late summer as well? Not technically repotting so just looking for clarification. I’m apologize if this info is covered elsewhere, a simple yes or no will suffice.
Thank you
I personally would collect these trees in spring. The reason is that one needs very good frost protection after collecting. I cannot provide this as I have almost 1000 trees and no possibility of save overwintering for extra ones. My Croatian students in Dalmatia, which is at the sea, collect in November and December, sometimes in January and February. They do not need super protection in winter as palm trees are growing close by.
 

Maloghurst

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I personally would collect these trees in spring. The reason is that one needs very good frost protection after collecting. I cannot provide this as I have almost 1000 trees and no possibility of save overwintering for extra ones. My Croatian students in Dalmatia, which is at the sea, collect in November and December, sometimes in January and February. They do not need super protection in winter as palm trees are growing close by.
Thank you!
 

sorce

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This is my favorite part. The Nugget that really stuck with me when I met Walter.

it's getting better every day.
Why, of course!

Not only is energy divided in spring, but weather is getting hotter, worse, and as many of us know, early heat can be just as, or even more fatal then a late frost.

A late frost which, by the way, I believe a tree knows is coming. So if you repot 2 weeks before the last frost in spring, the tree won't be growing roots for 2 weeks.

Whereas in Late Summer, if you are set for an early frost in fall, the tree also knows this, so it will begin to grow roots like mad, even through the frost, because foliage is also mature, hard, capable of withstanding the cold.

In order to best work WITH a tree, you must realize how smart they are. Their will to live is great, in nature, Never as Bonsai.

We have to remember to do best by the tree as if it were in the ground, as if it were ....
Natural!

Aha! Uncovering the secrets of "naturalistic bonsai", it was never a design style!
Hehehehehe!

Where's the moon at? Bout to get to repotting!

Sorce
 

Cable

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One of the best things about late summer potting: 'Yo leave the full canopy - do not cut roots and folate at the same time. You can cut roots, but you do not always have to. Don't forget that root cutting is severely weakening a tree. But if you have to and leave the full canopy new roots will grow much quicker than in spring. In spring the tree puts all it's strength into new foliage. If you then cut roots the tree has to make a decision here and divide it' strength. There is no new energy coming from the non-existing mature foliage and the new roots have to be fed from energy that was meant for foliage.



Sure you expose the canopy to full sun after late-summer repotting. Temperatures will go down quickly , days are shorter. The full sun on mature foliage will create energy to get lots of new roots quickly. The evaporation is there, but it's getting better every day.

In my garden the very best time is exactly now. In other gardens it will be one or two weeks or more later or even earlier. You have to figure out yourself.



This is why late summer repotting is the safest, saver than spring repotting. Also when you do root work. This is why I recommend to forget everything you thought you knew.



The full foliage is also important in spring for the same reason. This is why I advocate to pot as late as possible in spring with foliage already out for most trees. The full foliage which is not cut at the same time will send growing hormones to the roots (auxin) with the message 'grow fast everything is OK here I can support much more roots and need them). If you cut foliage the foliage would not send the message and as a s result the tree is not quite sure what to do.



Attached you see late summer (beginning of August) repotting of Japanese maple and trident maple And then spring repotting of Japanese maple. As one can see this is accompanied with heavy root pruning. So the claim that this man is southern Germany only buys top Japanese trees and repots them with no root work is ridiculous and exposes the writer as ignorant. These trees were exposed to full sun and grew happily after that.

These were absolutely not emergency repots. I could have chosen any day of the year. Does someone really think that I do all this just to show off how different my methods are? Would it not make much more sense that I do this with precious trees because it is the best for them.

All this information was written several times already in the past years. So the push to write it again is annoying and shows disrespect of my efforts. If you want something from me you have to do your homework first.
That's a really great explanation, thank you. I was debating whether or not to cut back the canopies on the three jap maples I just repotted but I decided not to and this reinforces my choice.
 

BunjaeKorea

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I think this really depends where you are. In Korea, China and Japan they re-pot flowering (Japanese) quince in late Autumn or Early winter to prevent the fungal spread of Quince root canker which spreads like mad in spring if you cut roots. The locality should impact on what techniques are used so the principles for doing re-potting may change depending of variables.
 

Forsoothe!

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Not only is energy divided in spring, but weather is getting hotter, worse, and as many of us know, early heat can be just as, or even more fatal then a late frost.
Sure you expose the canopy to full sun after late-summer repotting. Temperatures will go down quickly , days are shorter. The full sun on mature foliage will create energy to get lots of new roots quickly. The evaporation is there, but it's getting better every day.
Look at this Latitude-Time chart of the intensity and duration of sunlight. At Detroit's 42.6° latitude April 1st is just beginning intense sunlight, and August 1st intensity is high but diminishing. I store & start all my JM in full sun and move them to partial sun by June 1st. They like sun, but intensity and duration matters greatly. The intensity and duration of sunlight available from August 1st-on is just the kind that mature leaves need, not too intense and diminishing, and not too long and diminishing. The intensity in August is about the same as April/May, a period where we get great growth, but no crispyizing of edges.Latitude Time Chart.jpg
 
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Forsoothe!

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And one caveat: after extensive root work, never, ever, let the tree suffer from drought for one minute. Too wet for a few hours is much less damaging than too dry to support the foliage. Any day it doesn't rain, I water at least once.
 

Walter Pall

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Forsoothe,

This chart can be very useful. I am afraid the mark for Detroit is not correct. If I read this correctly Detroit is on 42 and you have done the black line at about 35. If I am correct then the blue line above your black one should be close to reality. Then the next blue like above it is for Munich, Germany which is at about 48 latitude.

If you then take mid-August and draw a vertical line down to the two horizontal lines you can see that Detroit and Munich are about a week apart - meaning it is cooler in Munich at middle of August when I have optimal time and it is a bit more sun still in Detroit.l This could mean that Detroit folks should wait a bit and go to August 20 or so to do late-summer repotting.

It also shows that there is about 8 weeks at least where it should be warm enough for the trees to still grow after mid-August in both places. Less in Munich than in Detroit.

if this is correct then everyone can find out about their latitude and find how far away they are from the situation in Munich (latitude 48) at mid-August. Then they can draw their conclusions from there.

Basically it shows what common sense tells us anyway. The more south the later you should do late-Sumer repotting and the earlier you can do spring repotting. The more north the earlier you shod do late-summer repotting and the later spring repotting.

This explains why in central Norway. they collect Scots pines in the bogs around end of July and get away with it. Oslo is at 59 latitude and about two and half weeks away from Munich according to the chart.

latitudde-and-sunlight.jpg
 

leatherback

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At Detroit's 42.6° latitude April 1st is just beginning intense sunlight, and August 1st intensity is high but diminishing.
I think this graph is mis-interpreted. It is an accumulated radiation per day, not the absolute intensity. Else, one would see more intense sunlight at the poles in peak summer than at the equator, which of course is not true. Only because of the day length the total wattage per surface area is high at the poles, not because of light intensity.
 

leatherback

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One again, I would not recommend using the graph in such a way. This is energy levels that hits the atmosphere over a 24hr period.

Being further from the poles mean longer summer days, and shorter winter days heavily influencing the accumulated colar irradiation for that day. Not per se meaning you have more energy per irradiated time unit (Say, per second). If in mid-summer you move from norway to the tropics, you will still get a heavy sunburn because direct sun intensity is much higher.

Furthermore, this is top of atmosphere. At higher latitudes the path for sunlight through the atmosphere is much longer than at the tropics (Lower sun angle), resulting in a reduced intensity of sunlight reaching the surface.

The graph is nice for energy budgetting of the earth as a system. They give an indication of the amount of energy available at the earth's surface but do not tell you how intense the sun at the surface will be.
 

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From my personal observation I created a ‘rule’ to protect my Japanese maples from sunburnt which is: when daytime temperatures rise above 21C I move them into the shade. This means that they stay in shade here from late May through late September. They only get maybe 1-2 hours of direct sun until 10 am. I still get some crispy leaves but nothing special compared to the first year. Something like this may also work for repotting...
 
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In the last week or so I have been repotting nursery stock: chinese junipers, mugo pines, colorado blue spruces, an eastern hemlock (Tsuga canadensis) and a smokebush in full leaf and still have eastern white cedars (thuja) to repot. All root bound in nursery containers and old soil to their first bonsai training pot. I performed the same as severe as necessary root work that i would have in spring. Of course showing a recently repotted conifer is not proof that it didn't impact the trees health but I can show you as proof the smokebush and the leafs did not for a moment show any sign of impact from the root work. In the attached photo the hemlock next to the smoke bush was also repotted (from a 3 gal container into this very small pot a few days ago).saKfm8SHRsqZe03VLbiF1g.jpg
 

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