Late summer repotting

Forsoothe!

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I only repot hardy trees when they have a full set of leaves, usually May-June-July. My thinking is that new roots are grown with the energy produced by the leaves. The more leaves, the more energy. The trees have to have enough time left in the growing season to mature buds for next season. I never repot in autumn, except greenhouse tropicals which can be repotted at any time (for me).
 

Walter Pall

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It is very simple. If someone manages to maneuver himself onto my personal ignore list he will not get a response, whatever he 'demands'. Most shut up then. Some get so irritated that they run amok and make it definitely clear why they are on that list.
 
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It baffles me the insolence, lack of respect for one of the most important bonsai professionals in the world and plain blindness to successful results of some folks in this forum, generally the same vocal ones. No matter how much logic in terms of horticulture or plant physiology and clear successful results. I could comment on specific points made by some of the rabid commenters here but I won't bother, discussing with these type of people is a mistake I won't make again. Is this style/technique prettier/better or uglier/worst, faster/slower than that is up for debate in this HOBBY. Are both way possible? For sure. There are multiple ways to style trees, and there are multiple ways to achieve the same results in terms of technique. Accept that there's more than one way to do anything in bonsai and leave it at that. The rabid people in this forum are making a disservice to Bonsai. If you like John Naka, follow his example help bonsai be a tool to connect people and bring peace and serenity to the world.
 

0soyoung

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As for late summer repotting , you bet. I am gearing up to apply it to a number of of evergreen conifers - with as minimal root work as necessary. and I will film it. and I will post it here.
Don't be so timid!
Actually push it. Like
  • wash the substrate out,
  • comb the roots radially,
  • flip the pot upside down,
  • trim the root pad to match the bottom of the pot, and
  • then pot back into the same pot (now right side up),
  • water it in, and
  • put it in the same 'full-sun' that it came from.
Use any pine, any fir, any spruce, any tsuga, any thuja, any chamaecyparis, any cryptomeria, any pseudotsuga, any juniper you've got.

I know that you are not in Alabama where trees burn up if touch them AND you are not in the perfect climates that I and Walter Pall are in. So. take note of the conditions the day you repot and for the week afterward: a) daily hi/low temperature, b) skies clear/overcast, c) relative humidity range (or the daily dew point).
 
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_#1_

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Accept that there's more than one way to do anything in bonsai and leave it at that.
If, say a Trident need major root work to improve the nebari, can you explain what you would do? Like time of year and process to start the tree in the right direction??

As for late summer repotting , you bet. I am gearing up to apply it to a number of of evergreen conifers - with as minimal root work as necessary. and I will film it. and I will post it here.
What if it calls for some root work? Will that jeopardize the tree's health? I would think most likely not though.
 

Walter Pall

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If, say a Trident need major root work to improve the nebari, can you explain what you would do? Like time of year and process to start the tree in the right direction??


What if it calls for some root work? Will that jeopardize the tree's health? I would think most likely not though.

To me late summer would be a good time also for root work, if you have to do it. I only warn people of too much root work. Is is not helpful and risks the tree, regardless of the time you do it. So do root work now. It will jeopardize the trees heath just as it would in spring. But one has to take risks, that#s for sure. 'To do nothing is not the solution.
 

Smoke

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It will jeopardize the trees heath just as it would in spring. But one has to take risks, that#s for sure. 'To do nothing is not the solution.

This quote does not make any horticultural sense at all. I don't care where you live. Who are the people you speak of that do nothing?
 

Smoke

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Actually I just did a repot on a trident that was showing signs of distress due to the pot being too shallow. I didn't repot this last spring and the pot was full of roots and had pushed too much soil up and it washes out when watering. It was planted on the bottom of the pot with no soil under. I repotted because I had to. Lose the tree or repot. I would never repot in summer as a replacement to spring repotting in my weather locale. I repotted when it was 106 degrees. 105 today. It was repotted last Tuesday.

The tree has responded well.
Last year the leaves were a yellow color and really never turned dark green. I suspect it was weak in the little soil it was in. Maybe 1/2 inch over the roots.

Let's see what it looks like this Friday.
033.JPG
 

Walter Pall

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This is a misunderstanding. 'To do nothing' means to not work on roots when it is called for. If there is an issue with the nebari then you have to do it. But some folks do root pruning because they have learned that this is good for the tree. It is not good per se, it is jeopardizing and weakening the tree. But one has to take that risk sometimes. To do nothing is not the solution.
 

BobbyLane

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So ... why is late summer repotting better then early spring repotting? After reading four pages I still don't get the answer. What are the benefits of late summer vs spring repotting? What can you expect? Can you expect stronger growth next year? But what if you don't want stronger growth, like you have a "finished" bonsai and you just want to keep the shape? Is late summer repotting better no matter in what development phase your bonsai tree is? Or it's only better for very old species? Is it better no matter how often and when you prune your trees? I can go on and on ... There are so many unanswered questions ...

I've watched a video where Mauro Stemberger collects oaks (quercus robur mostly) in December with great success. After collection he puts them in a big plastic bags and keep them in green house untill spring. While Harry Harrington can swear on late summer repotting/collecting quercus robur. I collected my two quercus robur in april, using Tony's Tickle black bag technique. One oak died while other one has been growing like crazy. I mean there are so many alternatives to spring repotting/collecting ... I wouldn't dare saying one is better then others. It might be better in ONE or TWO aspects of developing your trees but i doubt that it can cover ALL aspect of developing your trees.

Lol, thats probably because the OP doesnt say anything about summer repotting being better than spring.
you do realise, you can answer most of these questions with research and experimentation, with enough experience you can make your own rules.
Walter has his reasons why he chose to repot in late summer, everything is described clearly in regards to conifers and also his big maple.
Graham potter did a recent video on why he thinks summer repotting has yielded great results with his conifers in his climate....its out there, go check it out.
by then you should have enough info to carry out your own experiments.
 

Igor. T. Ljubek

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Lol, thats probably because the OP doesnt say anything about summer repotting being better than spring.
Well, he doesn't need to say it: with all due respect to mr. Walter Pall it's obvious that he believes (due his own experience) late summer repotting works better for him then spring repotting in cool climate. Why would he repott at this time of the year if he doesn't think so? Don't get me wrong: i would like to do some late summer repotting/collecting myself, but not before i get some infos.
I don't get answers to most of my questions with research. Is it so hard to write a few sentences about what are advantages and disadvantages (i am sure there are some) of late summer repoting?
 

BobbyLane

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Well, he doesn't need to say it: with all due respect to mr. Walter Pall it's obvious that he believes (due his own experience) late summer repotting works better for him then spring repotting in cool climate. Why would he repott at this time of the year if he doesn't think so? Don't get me wrong: i would like to do some late summer repotting/collecting myself, but not before i get some infos.
I don't get answers to most of my questions with research. Is it so hard to write a few sentences about what are advantages and disadvantages (i am sure there are some) of late summer repoting?

well, its already been said.....but once again, adverse weather conditions can be a factor.

did you happen to watch the G potter vid?
because its also been said that in his particular climate, he's faced disadvantages from repotting conifers in spring, namely adverse weather conditions.

regarding collecting. im pretty certain Harry harrington has documented success of collecting trees at various times of the year.
 

Paulpash

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I'm glad this thread was started but not because of the passion, vehemence and finger pointing.

Bonsai has never been black and white, night and day, Summer repot or Spring repot.

It is about trial and observation, actually watching the response of the tree when you apply any technique to it. Looking at extension growth, colour, leaf drop or bud set and then MAKING PERSONAL DECISIONS for you in your garden with your trees.

The internet and forumites cannot teach 'extent' - how much is too much? You have to learn this for yourself and it varies with every species. You will only learn this by doing, not reading. When your tree croaks it's because you've smashed the sweet Jesus out of all the feeders or you carve the crap out of it and the vascular system collapses. The penny soon drops when all your precious leaves follow suit.

It's the same with timing. The internet has shrunk a global conundrum (when to repot) into a microcosm (Bonsainut). If you want a true answer as to when to repot then use observation and common sense - actually walk outside, do it then watch what happens. The tree will tell you far better than "https://www.bonsainut.com/threads/late-summer-repotting.39595/page-5".
 
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BobbyLane

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I'm glad this thread was started but not because of the passion, vehemence and finger pointing.

Bonsai has never been black and white, night and day, Summer repot or Spring repot.

It is about trial and observation, actually watching the response of the tree when you apply any technique to it. Looking at extension growth, colour, leaf drop or bud set and then MAKING PERSONAL DECISIONS for you in your garden with your trees.

The internet and forumites cannot teach 'extent' - how much is too much? You have to learn this for yourself and it varies with every species. You will only learn this by doing, not reading. When your tree croaks it's because you've smashed the sweet Jesus out of all the feeders or you carve the crap out of it and the vascular system collapses. The penny soon drops when all your precious leaves follow suit.

It's the same with timing. The internet has shrunk a global conundrum (when to repot) into a microcosm (Bonsainut). If you want a true answer to when to repot then use observation and common sense - actually walk outside, do it then watch. The tree will tell you far better than "https://www.bonsainut.com/threads/late-summer-repotting.39595/page-5".
i couldnt have said it better myself
 
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We all did major root work in spring and if we did it well, the trees survived and we are confident that it works and we can reccomend to others and do it again. It is hard to break from the chains of what we've been doing for years but most people here attacking late summer repotting have never tried it. I suggest they do if they don't believe the evidence from others. It makes total horticultural AND plant physiology sense that a tree, deciduous or conifer can cope better with major root work in the late summer than in the spring in non-tropical climates. Here is why:

1. Heat is starting to ramp down so water requirements for evapotranspiration is easing in the late summer as opposed to the spring when it is ramping up.
2. In late summer if you have summer dormancy in your area the tree is not for a while requiring nutrients for either foliar or vascular growth as opposed to the spring when it needs them. Sure enough a refined tree needs less and that is why some refined trees are only fertilized in the fall. A tree in development however, needs all you can give. I venture to suggest, without any evidence, that the dogma of repotting in spring is in part also due to early folks in the west being told how to care for a refined tree as it was done in Japan. So if you have refined maple and no leafs in it a repot in the spring at the right time would seem logic. Yet we know that a refined maple can definitely be repotted in late summer. But early western access to bonsai knowledge probably meant copying the technique from Japan. In the document I published a few days ago on the stablishement of bonsai in the west there are references to some of the earlier instruction on bonsai care and probably that is where it all started.
3. A few days after a after a late summer repot the roots will start to regenerate with the help of the strong foliage it has and perfect conditions for photosynthesis and then start vascular growth prior to winter dormancy.
4. In the spring in many areas, mine included, spring can be cold and wet, if you worked your roots severely, the cold and dampness is an invitation for root rot, whereas late summer tends to be sufficiently sufficiently hot and humid to not favour such pathogens.

If trees evergreen or deciduous, conifer or broadleaf, can cope with the severe stress of repotting in the spring, they ought to be able to cope with it in late summer. Trees here in Canada are mostly collected in the late summer/early fall with disruption of roots during the collection process and they survive at rates depending probably more on the level of technique of the collector than the fact that they were collected in late summer or early fall.
 
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Cable

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When a lot of these "bonsai facts" pop up I like to compare them to how we do things at the nursery where I work. Especially since for us, doing something wrong horticulturally can cause thousands to millions of dollars in losses.

Below is a report of plants we re-potted in the past year. Note that most of these are not are-rooted but most will have at least root trimming.

FWIW, I ran this report for only "container" plants (which means no ball-and-burlap, no perennials, and no annuals).

Note: it was too big to post the exact dates and full names so here is the raw report for anyone interested: https://bit.ly/2ZEhW6T

MonthPlant
JanuaryALOCASIA
JanuaryAZALEA
JanuaryENSETE
JanuaryHYDRANGEA
JanuaryKOELREUTERIA
JanuaryMALUS
JanuaryMANDEVILLA
JanuaryMUSA
JanuarySYRINGA
FebruaryALOCASIA
FebruaryBETULA
FebruaryCERCIS
FebruaryCOLOCASIA
FebruaryHYDRANGEA
FebruaryMALUS
FebruaryMUSA
FebruaryROSE
FebruarySALIX
FebruarySYRINGA
FebruaryYUCCA
MarchACER
MarchAESCULUS
MarchALOCASIA
MarchAMELANCHIER
MarchBETULA
MarchBUXUS
MarchCARPINUS
MarchCATALPA
MarchCERCIDIPHYLLUM
MarchCERCIS
MarchCHIONANTHUS
MarchCLADRASTIS
MarchCOLOCASIA
MarchCORNUS
MarchCORYLUS
MarchCOTINUS
MarchCRATAEGUS
MarchDIOSPYROS
MarchEUCOMMIA
MarchEUONYMUS
MarchGERANIUM
MarchGINKGO
MarchGLEDITSIA
MarchGYMNOCLADUS
MarchHYDRANGEA
MarchJUNIPER
MarchKOELREUTERIA
MarchLIGUSTRUM
MarchLIRIODENDRON
MarchMAGNOLIA
MarchMALUS
MarchMETASEQUOIA
MarchMORUS
MarchOXYDENDRUM
MarchPICEA
MarchPLATANUS
MarchPOPULUS
MarchPRUNUS
MarchPYRUS
MarchQUERCUS
MarchROSE
MarchRUBUS
MarchSALIX
MarchSTEWARTIA
MarchSYRINGA
MarchTAXODIUM
MarchTAXUS
MarchTILIA
MarchULMUS
MarchVACCINIUM
MarchWEIGELA
MarchZELKOVA
AprilACER
AprilAMELANCHIER
AprilBERBERIS
AprilBETULA
AprilBRUGMANSIA
AprilBUXUS
AprilCERCIS
AprilCHAMAECYPARIS
AprilCLADRASTIS
AprilCORNUS
AprilCOTINUS
AprilDIOSPYROS
AprilEUONYMUS
AprilGLEDITSIA
AprilHALESIA
AprilHAMAMELIS
AprilHEPTACODIUM
AprilHIBISCUS
AprilHYDRANGEA
AprilHYPERICUM
AprilILEX
AprilITEA
AprilJUGLANS
AprilJUNIPER
AprilLINDERA
AprilMAGNOLIA
AprilMALUS
AprilMETASEQUOIA
AprilMICROBIOTA
AprilNYSSA
AprilPARROTIA
AprilPARTHENOCISSUS
AprilPICEA
AprilPINUS
AprilPLATANUS
AprilPRUNUS
AprilPYRUS
AprilQUERCUS
AprilROSE
AprilSPIRAEA
AprilSTYRAX
AprilSYRINGA
AprilTAXODIUM
AprilTAXUS
AprilTHUJA
AprilTSUGA
AprilULMUS
AprilVACCINIUM
AprilVIBURNUM
AprilWISTERIA
MayACER
MayAESCULUS
MayARONIA
MayAZALEA
MayBERBERIS
MayBETULA
MayBUDDLEIA
MayBUXUS
MayCALYCANTHUS
MayCAMPSIS
MayCARYOPTERIS
MayCHAMAECYPARIS
MayCLETHRA
MayCOREOPSIS
MayCORNUS
MayCORSO
MayCORYLUS
MayCOTINUS
MayCOTONEASTER
MayDEUTZIA
MayDIERVILLA
MayEUONYMUS
MayFAGUS
MayFOTHERGILLA
MayGAILLARDIA
MayGINKGO
MayHEPTACODIUM
MayHIBISCUS
MayHYDRANGEA
MayILEX
MayJUNIPER
MayLESPEDEZA
MayLIGUSTRUM
MayLONICERA
MayMAGNOLIA
MayMETASEQUOIA
MayMICROBIOTA
MayMYRICA
MayPHYSOCARPUS
MayPICEA
MayPIERIS
MayPINUS
MayPOTENTILLA
MayPRUNUS
MayRHODODENDRON
MayROSE
MayRUBUS
MaySALIX
MaySPIRAEA
MaySTEPHANANDRA
MaySYRINGA
MayTAXUS
MayTHUJA
MayVACCINIUM
MayVIBURNUM
MayVITEX
MayWEIGELA
MayWISTERIA
JuneABELIA
JuneACER
JuneAESCULUS
JuneAMELANCHIER
JuneARONIA
JuneAZALEA
JuneBERBERIS
JuneBETULA
JuneBUDDLEIA
JuneBUXUS
JuneCALYCANTHUS
JuneCAMPSIS
JuneCEPHALANTHUS
JuneCHAMAECYPARIS
JuneCORNUS
JuneCORYLUS
JuneCOTINUS
JuneCOTONEASTER
JuneDEUTZIA
JuneDIERVILLA
JuneEUONYMUS
JuneFAGUS
JuneFICUS
JuneFOTHERGILLA
JuneGINKGO
JuneHIBISCUS
JuneHYDRANGEA
JuneHYPERICUM
JuneILEX
JuneJUNIPER
JuneLEPTODERMIS
JuneLIGUSTRUM
JuneMAGNOLIA
JuneMALUS
JuneMYRICA
JuneOXYDENDRUM
JunePACHYSANDRA
JunePHILADELPHUS
JunePICEA
JunePIERIS
JunePRUNUS
JuneRHAMNUS
JuneRHODODENDRON
JuneRHUS
JuneROSE
JuneSALIX
JuneSCIADOPITYS
JuneSTEPHANANDRA
JuneSYRINGA
JuneTAXODIUM
JuneTAXUS
JuneTHUJA
JuneVACCINIUM
JuneVIBURNUM
JuneVINCA
JuneVITEX
JuneVITIS
JuneWEIGELA
JuneWISTERIA
JuneYUCCA
JulyACER
JulyARONIA
JulyASIMINA
JulyBERBERIS
JulyBETULA
JulyBUDDLEIA
JulyBUXUS
JulyCHAMAECYPARIS
JulyDEUTZIA
JulyDIERVILLA
JulyEUONYMUS
JulyFICUS
JulyFOTHERGILLA
JulyHIBISCUS
JulyHYDRANGEA
JulyHYPERICUM
JulyLINDERA
JulyMALUS
JulyMICROBIOTA
JulyPHYSOCARPUS
JulyPICEA
JulyPINUS
JulyPRUNUS
JulyRHUS
JulyRUBUS
JulySALIX
JulySAMBUCUS
JulySPIRAEA
JulySYRINGA
JulyTHUJA
JulyVIBURNUM
JulyVINCA
JulyWEIGELA
AugustACER
AugustAMELANCHIER
AugustARONIA
AugustAZALEA
AugustBERBERIS
AugustBETULA
AugustBUDDLEIA
AugustBUXUS
AugustCHAMAECYPARIS
AugustCORDYLINE
AugustCORNUS
AugustCOTINUS
AugustCOTONEASTER
AugustDIERVILLA
AugustEUCOMMIA
AugustEUONYMUS
AugustFORSYTHIA
AugustHIBISCUS
AugustHYDRANGEA
AugustILEX
AugustITEA
AugustJUNIPER
AugustKOELREUTERIA
AugustLIGUSTRUM
AugustLIRIODENDRON
AugustMALUS
AugustMETASEQUOIA
AugustMORUS
AugustPACHYSANDRA
AugustPHILADELPHUS
AugustPHYSOCARPUS
AugustPICEA
AugustPLATANUS
AugustPOPULUS
AugustPOTENTILLA
AugustPRUNUS
AugustQUERCUS
AugustRHAMNUS
AugustRHODODENDRON
AugustRHUS
AugustROSE
AugustRUBUS
AugustSALIX
AugustSAMBUCUS
AugustSORBARIA
AugustSPIRAEA
AugustSYRINGA
AugustTHUJA
AugustVIBURNUM
AugustVINCA
AugustWEIGELA
SeptemberACER
SeptemberAESCULUS
SeptemberAMELANCHIER
SeptemberARONIA
SeptemberAZALEA
SeptemberBETULA
SeptemberCALLICARPA
SeptemberCARAGANA
SeptemberCARPINUS
SeptemberCERCIDIPHYLLUM
SeptemberCERCIS
SeptemberCHIONANTHUS
SeptemberCISSUS
SeptemberCLADRASTIS
SeptemberCLETHRA
SeptemberCORDYLINE
SeptemberCORNUS
SeptemberCOTINUS
SeptemberCOTONEASTER
SeptemberDIOSPYROS
SeptemberEUCOMMIA
SeptemberEUONYMUS
SeptemberFORSYTHIA
SeptemberFOTHERGILLA
SeptemberGARDENIA
SeptemberGINKGO
SeptemberGYMNOCLADUS
SeptemberHALESIA
SeptemberHAMAMELIS
SeptemberHYDRANGEA
SeptemberILEX
SeptemberITEA
SeptemberKOELREUTERIA
SeptemberLIGUSTRUM
SeptemberLIQUIDAMBAR
SeptemberLIRIODENDRON
SeptemberMAGNOLIA
SeptemberMALUS
SeptemberMETASEQUOIA
SeptemberNYSSA
SeptemberPACHYSANDRA
SeptemberPARROTIA
SeptemberPHYSOCARPUS
SeptemberPICEA
SeptemberPLATANUS
SeptemberPRUNUS
SeptemberQUERCUS
SeptemberRHAMNUS
SeptemberRHODODENDRON
SeptemberRHUS
SeptemberSALIX
SeptemberSORBARIA
SeptemberSTYRAX
SeptemberSYMPHORICARPOS
SeptemberSYRINGA
SeptemberTAXODIUM
SeptemberTHUJA
SeptemberULMUS
SeptemberVIBURNUM
SeptemberVINCA
SeptemberYUCCA
OctoberACER
OctoberBUXUS
OctoberCARPINUS
OctoberCHAMAECYPARIS
OctoberGINKGO
OctoberGLEDITSIA
OctoberHALESIA
OctoberHEPTACODIUM
OctoberHYDRANGEA
OctoberILEX
OctoberJUNIPER
OctoberKOELREUTERIA
OctoberLIQUIDAMBAR
OctoberLIRIODENDRON
OctoberMAGNOLIA
OctoberMALUS
OctoberMETASEQUOIA
OctoberPICEA
OctoberPINUS
OctoberPLATANUS
OctoberPRUNUS
OctoberPYRUS
OctoberQUERCUS
OctoberSALIX
OctoberSCIADOPITYS
OctoberSTYRAX
OctoberSYRINGA
OctoberTAXODIUM
OctoberTHUJA
NovemberACER
NovemberAESCULUS
NovemberASIMINA
NovemberBRUGMANSIA
NovemberCARYA
NovemberCORNUS
NovemberEUCOMMIA
NovemberGINKGO
NovemberGYMNOCLADUS
NovemberHAMAMELIS
NovemberHYDRANGEA
NovemberILEX
NovemberJUGLANS
NovemberLIQUIDAMBAR
NovemberMACLURA
NovemberPLATANUS
NovemberQUERCUS
NovemberSASSAFRAS
NovemberSYRINGA
NovemberTAXUS
NovemberTHUJA
 
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