Late summer repotting

[Forsoothe!]

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]

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.

 

[Rafael Najmanovich]

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.

 

[Rafael Najmanovich]

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.

 

[0soyoung]

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).

 

[Smoke]

I have a few things I'd like to say here...








Just kidding.....

 

[_#1_]

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]

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]

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]

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.

 

[Walter Pall]

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]

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.

 

[Animron]

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]

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]

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".

 

[BobbyLane]

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

 

[Rafael Najmanovich]

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.

 

[sorce]

Amen @Paulpash !

Sorce

 

[Cable]

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

Month	Plant
January	ALOCASIA
January	AZALEA
January	ENSETE
January	HYDRANGEA
January	KOELREUTERIA
January	MALUS
January	MANDEVILLA
January	MUSA
January	SYRINGA
February	ALOCASIA
February	BETULA
February	CERCIS
February	COLOCASIA
February	HYDRANGEA
February	MALUS
February	MUSA
February	ROSE
February	SALIX
February	SYRINGA
February	YUCCA
March	ACER
March	AESCULUS
March	ALOCASIA
March	AMELANCHIER
March	BETULA
March	BUXUS
March	CARPINUS
March	CATALPA
March	CERCIDIPHYLLUM
March	CERCIS
March	CHIONANTHUS
March	CLADRASTIS
March	COLOCASIA
March	CORNUS
March	CORYLUS
March	COTINUS
March	CRATAEGUS
March	DIOSPYROS
March	EUCOMMIA
March	EUONYMUS
March	GERANIUM
March	GINKGO
March	GLEDITSIA
March	GYMNOCLADUS
March	HYDRANGEA
March	JUNIPER
March	KOELREUTERIA
March	LIGUSTRUM
March	LIRIODENDRON
March	MAGNOLIA
March	MALUS
March	METASEQUOIA
March	MORUS
March	OXYDENDRUM
March	PICEA
March	PLATANUS
March	POPULUS
March	PRUNUS
March	PYRUS
March	QUERCUS
March	ROSE
March	RUBUS
March	SALIX
March	STEWARTIA
March	SYRINGA
March	TAXODIUM
March	TAXUS
March	TILIA
March	ULMUS
March	VACCINIUM
March	WEIGELA
March	ZELKOVA
April	ACER
April	AMELANCHIER
April	BERBERIS
April	BETULA
April	BRUGMANSIA
April	BUXUS
April	CERCIS
April	CHAMAECYPARIS
April	CLADRASTIS
April	CORNUS
April	COTINUS
April	DIOSPYROS
April	EUONYMUS
April	GLEDITSIA
April	HALESIA
April	HAMAMELIS
April	HEPTACODIUM
April	HIBISCUS
April	HYDRANGEA
April	HYPERICUM
April	ILEX
April	ITEA
April	JUGLANS
April	JUNIPER
April	LINDERA
April	MAGNOLIA
April	MALUS
April	METASEQUOIA
April	MICROBIOTA
April	NYSSA
April	PARROTIA
April	PARTHENOCISSUS
April	PICEA
April	PINUS
April	PLATANUS
April	PRUNUS
April	PYRUS
April	QUERCUS
April	ROSE
April	SPIRAEA
April	STYRAX
April	SYRINGA
April	TAXODIUM
April	TAXUS
April	THUJA
April	TSUGA
April	ULMUS
April	VACCINIUM
April	VIBURNUM
April	WISTERIA
May	ACER
May	AESCULUS
May	ARONIA
May	AZALEA
May	BERBERIS
May	BETULA
May	BUDDLEIA
May	BUXUS
May	CALYCANTHUS
May	CAMPSIS
May	CARYOPTERIS
May	CHAMAECYPARIS
May	CLETHRA
May	COREOPSIS
May	CORNUS
May	CORSO
May	CORYLUS
May	COTINUS
May	COTONEASTER
May	DEUTZIA
May	DIERVILLA
May	EUONYMUS
May	FAGUS
May	FOTHERGILLA
May	GAILLARDIA
May	GINKGO
May	HEPTACODIUM
May	HIBISCUS
May	HYDRANGEA
May	ILEX
May	JUNIPER
May	LESPEDEZA
May	LIGUSTRUM
May	LONICERA
May	MAGNOLIA
May	METASEQUOIA
May	MICROBIOTA
May	MYRICA
May	PHYSOCARPUS
May	PICEA
May	PIERIS
May	PINUS
May	POTENTILLA
May	PRUNUS
May	RHODODENDRON
May	ROSE
May	RUBUS
May	SALIX
May	SPIRAEA
May	STEPHANANDRA
May	SYRINGA
May	TAXUS
May	THUJA
May	VACCINIUM
May	VIBURNUM
May	VITEX
May	WEIGELA
May	WISTERIA
June	ABELIA
June	ACER
June	AESCULUS
June	AMELANCHIER
June	ARONIA
June	AZALEA
June	BERBERIS
June	BETULA
June	BUDDLEIA
June	BUXUS
June	CALYCANTHUS
June	CAMPSIS
June	CEPHALANTHUS
June	CHAMAECYPARIS
June	CORNUS
June	CORYLUS
June	COTINUS
June	COTONEASTER
June	DEUTZIA
June	DIERVILLA
June	EUONYMUS
June	FAGUS
June	FICUS
June	FOTHERGILLA
June	GINKGO
June	HIBISCUS
June	HYDRANGEA
June	HYPERICUM
June	ILEX
June	JUNIPER
June	LEPTODERMIS
June	LIGUSTRUM
June	MAGNOLIA
June	MALUS
June	MYRICA
June	OXYDENDRUM
June	PACHYSANDRA
June	PHILADELPHUS
June	PICEA
June	PIERIS
June	PRUNUS
June	RHAMNUS
June	RHODODENDRON
June	RHUS
June	ROSE
June	SALIX
June	SCIADOPITYS
June	STEPHANANDRA
June	SYRINGA
June	TAXODIUM
June	TAXUS
June	THUJA
June	VACCINIUM
June	VIBURNUM
June	VINCA
June	VITEX
June	VITIS
June	WEIGELA
June	WISTERIA
June	YUCCA
July	ACER
July	ARONIA
July	ASIMINA
July	BERBERIS
July	BETULA
July	BUDDLEIA
July	BUXUS
July	CHAMAECYPARIS
July	DEUTZIA
July	DIERVILLA
July	EUONYMUS
July	FICUS
July	FOTHERGILLA
July	HIBISCUS
July	HYDRANGEA
July	HYPERICUM
July	LINDERA
July	MALUS
July	MICROBIOTA
July	PHYSOCARPUS
July	PICEA
July	PINUS
July	PRUNUS
July	RHUS
July	RUBUS
July	SALIX
July	SAMBUCUS
July	SPIRAEA
July	SYRINGA
July	THUJA
July	VIBURNUM
July	VINCA
July	WEIGELA
August	ACER
August	AMELANCHIER
August	ARONIA
August	AZALEA
August	BERBERIS
August	BETULA
August	BUDDLEIA
August	BUXUS
August	CHAMAECYPARIS
August	CORDYLINE
August	CORNUS
August	COTINUS
August	COTONEASTER
August	DIERVILLA
August	EUCOMMIA
August	EUONYMUS
August	FORSYTHIA
August	HIBISCUS
August	HYDRANGEA
August	ILEX
August	ITEA
August	JUNIPER
August	KOELREUTERIA
August	LIGUSTRUM
August	LIRIODENDRON
August	MALUS
August	METASEQUOIA
August	MORUS
August	PACHYSANDRA
August	PHILADELPHUS
August	PHYSOCARPUS
August	PICEA
August	PLATANUS
August	POPULUS
August	POTENTILLA
August	PRUNUS
August	QUERCUS
August	RHAMNUS
August	RHODODENDRON
August	RHUS
August	ROSE
August	RUBUS
August	SALIX
August	SAMBUCUS
August	SORBARIA
August	SPIRAEA
August	SYRINGA
August	THUJA
August	VIBURNUM
August	VINCA
August	WEIGELA
September	ACER
September	AESCULUS
September	AMELANCHIER
September	ARONIA
September	AZALEA
September	BETULA
September	CALLICARPA
September	CARAGANA
September	CARPINUS
September	CERCIDIPHYLLUM
September	CERCIS
September	CHIONANTHUS
September	CISSUS
September	CLADRASTIS
September	CLETHRA
September	CORDYLINE
September	CORNUS
September	COTINUS
September	COTONEASTER
September	DIOSPYROS
September	EUCOMMIA
September	EUONYMUS
September	FORSYTHIA
September	FOTHERGILLA
September	GARDENIA
September	GINKGO
September	GYMNOCLADUS
September	HALESIA
September	HAMAMELIS
September	HYDRANGEA
September	ILEX
September	ITEA
September	KOELREUTERIA
September	LIGUSTRUM
September	LIQUIDAMBAR
September	LIRIODENDRON
September	MAGNOLIA
September	MALUS
September	METASEQUOIA
September	NYSSA
September	PACHYSANDRA
September	PARROTIA
September	PHYSOCARPUS
September	PICEA
September	PLATANUS
September	PRUNUS
September	QUERCUS
September	RHAMNUS
September	RHODODENDRON
September	RHUS
September	SALIX
September	SORBARIA
September	STYRAX
September	SYMPHORICARPOS
September	SYRINGA
September	TAXODIUM
September	THUJA
September	ULMUS
September	VIBURNUM
September	VINCA
September	YUCCA
October	ACER
October	BUXUS
October	CARPINUS
October	CHAMAECYPARIS
October	GINKGO
October	GLEDITSIA
October	HALESIA
October	HEPTACODIUM
October	HYDRANGEA
October	ILEX
October	JUNIPER
October	KOELREUTERIA
October	LIQUIDAMBAR
October	LIRIODENDRON
October	MAGNOLIA
October	MALUS
October	METASEQUOIA
October	PICEA
October	PINUS
October	PLATANUS
October	PRUNUS
October	PYRUS
October	QUERCUS
October	SALIX
October	SCIADOPITYS
October	STYRAX
October	SYRINGA
October	TAXODIUM
October	THUJA
November	ACER
November	AESCULUS
November	ASIMINA
November	BRUGMANSIA
November	CARYA
November	CORNUS
November	EUCOMMIA
November	GINKGO
November	GYMNOCLADUS
November	HAMAMELIS
November	HYDRANGEA
November	ILEX
November	JUGLANS
November	LIQUIDAMBAR
November	MACLURA
November	PLATANUS
November	QUERCUS
November	SASSAFRAS
November	SYRINGA
November	TAXUS
November	THUJA

 

[Colorado]

lost me when we started lumping in spring vs. summer reporting with racism and sexism.