Repotting big maple

[AlainK]

And then my own knowledge and style still changes. It is not helpful if you quote me what I wrote in 2007. I would have never done late summer repotting with precious maples then.

Only fools never change their minds.

I've changed my mind on many aspects of bonsai cultivation : the more you know the species you cultivate, the more your "techniques" evolve. For instance, when you've lost mugo pines when repotting in spring but then repotted them in August and they're healthy, why would you get back to what doesn't seem to work well with your trees, in your environment?

 

[Anthony]

Too many hanging on to Mr. Pall as a Bonsai God.

He is evolving.

Experience costs.
Good Day
Anthony

*That is how we repot as well. Mr.Pall's images.
Save we use a very sharp Chinese chopper.

 

[Ruben Bouwmeester]

Very interesting too see @Walter Pall. Thanks for sharing and telling your knowledge. Danke

 

[AlainK]

Experience costs

Oh yes...

But that's an investment.

 

[ralf]

hello, what is the best period to repot palmatum tree for you ?
I recently learnt that some Japanese Master (at least one) repot in Autumn, after the autumn color leaves, to avoid the spring "sap hemorragy" from the cut on branches

Spring, once the buds move. March to April based on the biotope you live. You can do it in the Autumn but for that I would prefer to keep the plant in frost free area ( tems ranging from 0-5°C ). I believe your information about the change of the colour of the leaves is about pruning to avoid bleedig. Light pruning though. Structural pruning on Maples/Birches etc is better in late spring/early summer in my experinece.

 

[clem]

Spring, once the buds move. March to April based on the biotope you live. You can do it in the Autumn but for that I would prefer to keep the plant in frost free area ( tems ranging from 0-5°C ). I believe your information about the change of the colour of the leaves is about pruning to avoid bleedig. Light pruning though. Structural pruning on Maples/Birches etc is better in late spring/early summer in my experinece.

Interesting. Yes i observed that it is good to prune in June/july/august because the tree still grow shoots and you can have bud emerging without any sap bleeding. It is said, in books to prune just before repotting in spring to avoid sap bleeding but i observed personnaly a sap bleeding (very difficult to stop) after repotting and structural pruning in March. I did cut the trunk to make conicity better so the sap bleeding was very impressive. It is also advised -in books- to prune just when the leaves have fallen down in Autumn too but i got a sap withdrawal.. So i agree with you, i prefer to cut during summer.
Although i find interesting the late summer/early autumn repotting, i prefer the spring repotting too but it would be interesting to try this late summer repotting

 

[ralf]

Although i find interesting the late summer/early autumn repotting, i prefer the spring repotting too but it would be interesting to try this late summer repotting

I do not see any advantage as far as the tree is concerned. The late summer and autumn growing season is for accumulation of energy and not about repairing damage. Because of the transpiration you must keep some volume of hair roots ( how much is enough? ) and preferably keep the tree in the frost free area during the winter. In the place I live there are quite hard frosts without the snow cover and I do experience a lot of damage on new roots of plants airlayered in the late summer. So it should be the same for the new roots after late summer repoting. The potential damage for the tree is quite high to test the feasibility ( FOR ME ). Regadless of the costs of the tree. Respect.
I can achieve at least the same results with a partial removal of the top soil&cutting of problematic roots and stirring in the new substrate. But thats me. Btw to be fair with Mr Pall I am still on partial organic substrate.

Happy to see people testing new approches/paving the way forward. But still I do select those that make sence for me and skip the ones that don't.

 

[leatherback]

The nice thing about summer repotting is that trees grow more roots in fall than in the rest of the year. This has to do with storage for winter. So by root-pruning now, you allow the tree to use all the sugars and other nutrients that now sit in the foliage, trunk and twigs in spring: It will put those in the roots that you would trim off in spring during a spring-repot.

@Walter Pall : I notice that you do not do a full bare-rooting of the tree. This means there will be plenty of root-tips active in the repotted tree, aiding in the tree keeping turgor up. How do you handle younger, more recently collected material? I can imagine that when you are still working on the initial refinement of roots (So you need to remove thick main roots) that you would prefer a spring repot, or a defoliated tree. Or does a full soil swap & root reduction also pose no real problems in summer?

 

[clem]

I do not see any advantage as far as the tree is concerned. The late summer and autumn growing season is for accumulation of energy and not about repairing damage. Because of the transpiration you must keep some volume of hair roots ( how much is enough? ) and preferably keep the tree in the frost free area during the winter. In the place I live there are quite hard frosts without the snow cover and I do experience a lot of damage on new roots of plants airlayered in the late summer. So it should be the same for the new roots after late summer repoting. The potential damage for the tree is quite high to test the feasibility ( FOR ME ). Regadless of the costs of the tree. Respect.
I can achieve at least the same results with a partial removal of the top soil&cutting of problematic roots and stirring in the new substrate. But thats me. Btw to be fair with Mr Pall I am still on partial organic substrate.

.

I still use akadama for my deciduos trees.. and a mix of pumice/pouzzolane for conifers.
Concerning winter frost, do you have long time frost in your area ? (Saxony in Deutschland) In my area (Normandy France) there can be a few days (3 or 4 max) with frost , so i put the favorite trees in a veranda kept frost free and for the other trees i dig the pots in the ground with straw on the surface.
If you repot also in spring or in Autumn, if you have 3 or more days of frost, you can have roots damage, don't you ?

 

[ralf]

The nice thing about summer repotting is that trees grow more roots in fall than in the rest of the year. This has to do with storage for winter.

No. The other way round. Roots growth promoted by new shoots. More new shoots more roots. Late spring till mid of summer. Then steady decline. The tree is not a carrot so it stores much more energy in the sections above soil level. Sorry, I cannot help.

 

[leatherback]

No. The other way round. Roots growth promoted by new shoots. More new shoots more roots. Late spring till mid of summer. Then steady decline. The tree is not a carrot so it stores much more energy in the sections above soil level.

I guess we differ of opinion and information sources

 

[ralf]

I guess we differ of opinion and information sources

Never mind. We still have a good time with bonsai

 

[Walter Pall]

The nice thing about summer repotting is that trees grow more roots in fall than in the rest of the year. This has to do with storage for winter. So by root-pruning now, you allow the tree to use all the sugars and other nutrients that now sit in the foliage, trunk and twigs in spring: It will put those in the roots that you would trim off in spring during a spring-repot.

@Walter Pall : I notice that you do not do a full bare-rooting of the tree. This means there will be plenty of root-tips active in the repotted tree, aiding in the tree keeping turgor up. How do you handle younger, more recently collected material? I can imagine that when you are still working on the initial refinement of roots (So you need to remove thick main roots) that you would prefer a spring repot, or a defoliated tree. Or does a full soil swap & root reduction also pose no real problems in summer?

Younger material is treated the same way. On young trees you can cut off more roots because they are more vigorous and will grow faster than older ones. Forget this idea that spring is the better time basically. Also forget forever 'fall repotting'. It is late summer repotting, the earlier the BETTER. Depending on your climate and weather situation from beginning of August to end of August is the best time for old and young trees. They MUST get winter protection. And I usually do this mainly on maples. have not tried it much on other kinds.

 

[Walter Pall]

Can you also read or onyy write? If you continue like this I will stop posting here again. I do NOT owe anybody here anything. I have explained at length why I do this and you only have to find it.

This I found in two seconds:
Do not cut off too much roots, do not cut off foliage. After care it needs much less than in spring. This is one of the best things about it. The days get shorter, temperatures get down slowly, it rains more, humidity in the air is higher, much more due overnight. Water thoroughly after repotting - everything, also the foliage must be dripping wet. Then water once every day thoroughly, start feeding immediately, tree should not be in full sun all day, rather half shade, sun in the morning and shade in the afternoon is best. You must use modern substrate - absolutely no soil. You must leave the foliage on. Do not cut anything until October. Water every day all over the tree. Only on very hot days water twice. If you don't have much to do you can mist the tree several times a day. Frost free winter protection is a must.

Why does this work so well and better than in spring? Because the tree has perfect conditions now to grow roots until the end of October. This is why now! Earlier is better than later to have more time for root growth. This is eight weeks and sufficient.

Roots only grow now if there is plenty of foliage that creates energy for that. If you have not cut any branches the terminal buds will send signals to the roots with hormones called auxin that signal to grow. If that signal is not there the roots will hesitate.

The tree must get frost free over-wintering. In next spring it will start as if nothing happened.

If you repot in spring there is no foliage yet to help the roots to grow, the tree must do this out of stored energy. The energy was stored for foliage growth and not for root growth and the tree will be weakened. The foliage in spring will grow into an environment which gets worse every day, days longer, temperatures higher, humidity lower every day. The foliage will find it hard to grow well. It will quickly be too much to be supported by the existing roots - especially if you have cut off many. You have to cut short very soon after the shoots have stretched in order to avoid too much foliage mass which cannot be supported by the roots. The tree is weakened all the time by these measurement. It has a tough first summer after repotting. After two years the same again and people wonder why their trees are not doing well,m why thy do not get anywhere and stagnate.

 

[Cosmos]

Do the roots grow most/fastest during this time (as @leatherback put it, "more roots in fall than in the rest of the year") ? I don't know. How do you know this @leatherback ? Or did you simply mean that the tree does grow roots during the fall, but maybe overemphasized that point with hyperbole? It's unclear to me what @Walter Pall thinks/knows about this.

Larry Morton, Modern Bonsai Practice: 501 Principles of Good Bonsai Horticulture.

This book was controversial on this forum, partly because a lot of sources cited relate to full-size trees in the ground.

 

[rockm]

Wow, can't believe the static Walter is getting. It's not a secret that Japanese maples have a "secondary" repotting option in the late spring into summer after their leaves harden off. As Walter said, don't take off too much though, shelter it a bit from too much sun and wind, and insure the tree isn't subjected to a harsh winter.

Late spring/early summer repotting for Japanese Maples is not "better" than earlier in the spring. It can be more convenient though.

It can be great if you didn't get to some particular trees in early spring -- I had issues this spring with the weird weather and let my JMs alone even though they need to be root pruned badly. Also soil and drainage can "break down" sometimes after more traditional repotting season has passed. The later repotting time can help with both of those things.

 

[cmeg1]

Why would you assume that you could threaten this community with your departure?

It would affect someone like me that has grown into Bonsai through the years at whatever pace and can reminisce about good times reading Walter Pall trees!
It is very exciting to have Bonsai people like him show his work.......

 

[Saddler]

Why would you assume that you could threaten this community with your departure? It is true that you do not owe us anything, and we would all be very understanding if our questions did not receive answers. However, we would all love to learn as much as we can from you.

Most of what you copy-pasted are instructions about the procedure and care after the procedure. With regards to why late-summer is better than spring for repotting (maples in all stages of development?), I am understanding the following:

reason 1: One of the best things about late-summer repotting is that it requires less care after the repotting (you then go on to list the care requirements after repotting, which are indeed pretty 'normal' care procedures).

reason 2: the tree has better environmental condition in late-summer (in opposition to to spring) to grow roots. (An eight-week time frame is sufficient).

reason 3: the tree has foliage in order to produce roots

One of your conditions is that not too many roots be removed. What about when you need to remove a lot of roots, or bare root a tree? Is spring still the appropriate time for this?

Thank you

The reason he is doing this repotting in August is so the tree isn’t slowed down in its growth. Read more carefully! Why would spring not be the appropriate time to barefoot anymore? What has changed there?

 

[ralf]

Talking about roots and the seasonality of their growth.: The reasonable thick roots looks great when they form the nebari. Below surface I would prefer to have as much fibre/hair roots as possible.
Regarding their growth pattern and influencers - https://irinsubria.uninsubria.it/re...950320/3207/Montagnoli14 (Eur.J.For.Res.).pdf.
I guess the conditions in the pot will make it different in terms of timig of the peaks p.962 Higher soil temps. Regular water supply.

In terms of hair roots storage capacity - I have doubts it is comparable with the section of the tree above the ground.

 

[Saddler]

Based on @Walter Pall 's post, i was wondering whether he now recommends that one only, or at least primarily, use late-summer repotting of trees (in all stages of development) and consequently restrict spring repotting (currently the most common period for repotting, from what I understand) for specific trees with particular developmental needs (example: severe root work).

@Walter Pall yes, i know I can go look at your photo gallery for proof that your method works on very expensive trees. I'm not doubting you, I just want to make sure that I apply your excellent methods correctly to my trees.

I don’t think he recommending anything. It is what he does. Do with it what you will. Remember it’s only one trick in a bag of many for trees. If you don’t know why ore when to use a technique, maybe you shouldn’t be using it yet, or at most using it on a tree you don’t mind killing.

Are you even able to keep a tree frost free at -30° even in your stairwell? You are asking all these questions but have you considered if this is even possible for you? Even with my mild winters I can’t overwinter a tree and guarantee no frost with my current situation.