Repotting in late autumn

[Baku1875]

this January, london booked temps just below 20F on Jan 23. Risky!
2 weeks with lows under 30F, and Feb 8 hit 25F. Enough to do damage to a Fall repotted bonsai?

 

[BobbyLane]

This was a Nov buy and repot, I dont get them in my car unless I reduce on the spot. No problem. I have many threads like this, so people can do their own research.

Hornbeam-The Ram

Picked this one up at start of nov. it was a 6ft tall tree at the nursery. these are rootballed trees, so it would have just been dug from a field for the bare root season. I bring all my tools to the nursery and reduce the tree to a managable size on the spot. with (bow saw, loppers...

www.bonsainut.com

I sold it the next season,

 

[James89]

Thank you for the replies they have been interesting reading.

What issues with Spring repotting are you trying to overcome with late-autumn repotting?

I am not trying to overcome any issue. I found the talk interesting and thought this would be a place to ask others opinions on the subject.

Do the math--sever roots in spring--6 months of regeneration/nutrient storage time. Maximizes root activity in the fall--Sever roots in the late summer you will get possibly three months of growth before dormancy if you're lucky... That timing also removes resources accumulated during the spring summer. Root growth slows and/or ceases when soil temps drop below 35 or so. With fall root pruning you're betting on a mild winter--which might be the case in the U.K.--most of the time, but in most of North America, we get substantially low wintertime temperatures.

The fall repotting stuff comes up all the time, but it's simply a mostly lesser alternative to springtime repotting. It's not some new discovery.

Would you not be removing those resources during a spring repot anyway? The autumn repot would allow the root system to recover to allow fertilising earlier in the spring but I agree the tree will need protection which was mentioned.

 

[rockm]

Thank you for the replies they have been interesting reading.

I am not trying to overcome any issue. I found the talk interesting and thought this would be a place to ask others opinions on the subject.

Would you not be removing those resources during a spring repot anyway? The autumn repot would allow the root system to recover to allow fertilising earlier in the spring but I agree the tree will need protection which was mentioned.

Well, yeah. Any time you root prune you're removing resources. Removing those resources just before roots begin growing however, is different than removing them at the end of the process. The roots removed in the spring have 5-6 months to build up their strength, in preparation for the next active growth period in the Spring. The root prune in the fall removes those resources and gives only a few weeks to build up strength for the coming spring.

 

[Paradox]

Seems like the OP has made up their mind and just wants to repot in the fall because he watched one video about it.

Doesn't matter what 95-99% of all other bonsai practitioners all over the world do and have done for 100s of years or what the reality is about how trees actually grow and physiologically respond to season changes.

Its been repeated several times, they just dont want to believe it so no point wasting more time trying to convince them otherwise.

Their tree(s), they can do as they wish.
Good luck

 

[BobbyLane]

spring isnt the only time you can safely repot trees here in the UK. Its as simple as that really. Nothin more to add.
btw, not just the UK, but in parts of Europe, they repot yamadori carpinus orientalis around Nov. These trees are worth 1000s. Maybe they dont know what theyre doing.

 

[BobbyLane]

Check the time stamps...
Op I suggest you do your research closer to home and carry out your own experiments. I gave you a list of names to look up.
Btw this is in Croatia

 

[James89]

Seems like the OP has made up their mind and just wants to repot in the fall because he watched one video about it.

Doesn't matter what 95-99% of all other bonsai practitioners all over the world do and have done for 100s of years or what the reality is about how trees actually grow and physiologically respond to season changes.

Its been repeated several times, they just dont want to believe it so no point wasting more time trying to convince them otherwise.

Their tree(s), they can do as they wish.
Good luck

I have made up my mind to experiment with it yes. I thought it would be an interesting topic to discuss I apologise if you feel I have wasted your time.

Check the time stamps...
Op I suggest you do your research closer to home and carry out your own experiments. I gave you a list of names to look up.
Btw this is in Croatia

Thank you. I appreciate the suggestions and will do some more research. I like the bonsai4me site and will check out Grahams work

 

[Baku1875]

this is why it's important to have a nuanced conversation.

What I want to know is- do the professionals who repot in November do it to meet exhibition goals, to have a tree show ready sooner, etc...or do they do it because it is 'the optimal best practice for the tree's long term and short term health'.

One thing is being ABLE to do something, another is whether or not that something is a 'best-practice' or a stopgap measure to meet another goal.

Can it be done? is different from- should it be done? and what is the margin of error and consequences if conditions aren't as expected?

 

[James89]

this is why it's important to have a nuanced conversation.

What I want to know is- do the professionals who repot in November do it to meet exhibition goals, to have a tree show ready sooner, etc...or do they do it because it is 'the optimal best practice for the tree's long term and short term health'.

One thing is being ABLE to do something, another is whether or not that something is a 'best-practice' or a stopgap measure to meet another goal.

Can it be done? is different from- should it be done? and what is the margin of error and consequences if conditions aren't as expected?

My understanding is that it was for the trees benefit not to meet exhibition goals, they believed this was the best time to do the work. The person giving the talk I listened to specialized in improving the root system before passing the trees on to members that were more skilled in styling. In hindsight I should have asked some questions at the meeting. I will be joining her club when my evenings become free so I will pick her brain on the topic.

 

[BobbyLane]

Take off the bonsai rose tinted goggles for a moment.

 

[leatherback]

I do repot yearround. I am sorry @Deep Sea Diver to be part of the ever increasing volume of youtube videos on bonsai. I do however try and nuance when I do things out of the recommended season. I do wish people would every once in a while try new things, so I do hint upon alternatives.

In fact, I did extensive rootwork to a trident maple last weekend. Because I believe tridents respond well when it is warmer. I am listening also to people like @Walter Pall who have excellent and valuable trees added with a sauce of decades of experience.

In later summer (early fall) trees move LOADS of resources around from the foliage into longer-term storage. They clean house before winter, getting setup for spring. So repotting in this period that the foliage turns (For us, early october-ish) is a great time to look into repotting, in my opinion.

WIth a snap-shot flips between too cold for the tree to repot and in full leave (This year my beeches went from buds closed to fully extended in less than 10 days) the 'optimal' repotting window gets increasingly hard to hit. I have found that I can pretty much repot all the time. As @BobbyLane indicates: Bare-root replanting season of trees and shrubs by commercial nurseries is ~October-April. Why would that be any different for bonsai.

 

[Shibui]

Down here we get frost but not what I assume the north Americans call freeze. I know that pine roots are active all winter here so certainly in some places trees do have the capacity to regrow roots after an autumn repot.
We have a few very experienced growers who are now repotting some trees in autumn and no problems reported so far.

Doesn't matter what 95-99% of all other bonsai practitioners all over the world do and have done for 100s of years or what the reality is about how trees actually grow and physiologically respond to season changes.

Interesting to read through the posts here. All those against it appear to never have tried. All the replies against seem to be conjecture and theory. Those who have tried appear to be all for autumn repotting because they have found it works for them.
There may be something in climate but we won't really know until some growers in cooler climates do some proof of concept testing.

 

[Vali]

I believe nobody should say for sure that it cannot be done as long as some people have done it.
I collected 2 lindens on november 21st 2019, planted one in the ground and one in a crate to make it a bonsai. They had very few roots and, despite the fact that 2-3 nights after that we had a frost, they both live and are doing great at this moment. The one in the crate spent it's winter protected somewhat, but not at all frost free. The substrate was frozen for most of the winter.

 

[BobbyLane]

I havn't had much success with conifers at any time of the season. G potter has been repotting conifers in summer and talks about his results in this video.
you can pick up a substantial nursery spruce with a thick trunk at this time of year for around £30 in most nurseries across the UK, maybe even cheaper. If I selected one now I would probaby leave the top foliage alone and experiment with a repot. But you would also have the option to leave everything until spring and some even repot conifers over Autumn/winter.

 

[James89]

I havn't had much success with conifers at any time of the season. G potter has been repotting conifers in summer and talks about his results in this video.
you can pick up a substantial nursery spruce with a thick trunk at this time of year for around £30 in most nurseries across the UK, maybe even cheaper. If I selected one now I would probaby leave the top foliage alone and experiment with a repot. But you would also have the option to leave everything until spring and some even repot conifers over Autumn/winter.

I was planning on buying a group of trees. I am undecided on what and to repot half in November and half in spring and track their progress

 

[fredman]

Late summer repotting...WP

https://www.bonsainut.com/threads/late-summer-repotting.39595/

 

[Dav4]

I've historically re-potted all my trees in mid/late winter to mid spring, depending on species and location and I've had great success with that approach and don't intend to change. With that being said, I can say that tree roots do, in fact, continue to grow during the "dormant season", assuming the tree is healthy and the temperature at the root zone is appropriate- I'm guessing north of mid/upper 30's F. There have been at least 2 or 3 occasions where I pulled the mulch from around maples in nursery cans in early spring to find roots escaping from the drainage holes and growing several inches into the mulch, and the top of the mulch on these trees was assuredly frozen from January into March. My takeaway here is that you can perform moderate fall root work and be successful but you've got to be selective and know your micro-climate well. Work a tree in questionable health, be too aggressive in the root work, or have an unusually cold or wet winter and you'll likely lose trees.