severe root pruning a maple: how to transition from a big nursery pot to a bonsai pot - help wanted!

[Deleted member 21616]

I'm hoping the long title of this thread will help others in my situation find this thread in the future. From what I have been able to find, the information on this is scattered here and there, and it is even often unclear what species people are discussing. I spent the last two days reading posts dating back to 2013, taking notes, and trying to develop a plan of action for this tree. I do understand that there are many different views about the methods and process.

I reserved an Aka Shigitatsu Sawa, which will be overwintered at Vineland nursery near Niagara Falls. I'm scheduled to pick it up in May (the leaves will have already emerged).

Over the past 15 years, this tree has been grown in pots ranging from 1-8 gallons by a nursery that specializes in landscape trees, and especially japanese maples.

I would like to transition this tree from its current 8 gallon pot, to a bonsai pot. I am in no rush; i would prefer to do this with minimal risk.

The tree stands about 40" tall from soil level, and I expect the finished project to be within the range of 48-60". It will be styled/trained/worked like a massive bonsai tree, but with necessarily looser aesthetic standards, of course (i.e. i'm not especially worried about developing trunk taper, for example).

At the moment, I am especially confused about:

1 - whether i should defoliate at the time of rootwork. If rootwork is done at bud swell, there are no leaves on the tree to defoliate. Should they be defoliated when they emerge?

2 - over how many 'stages' or seasons should i divide the root work? Should it be cut back by 25% each year over the next 3-4 years?

3 - how does one encourage fine feeder roots near the trunk (although i was told japanese maples in general tend to produce shallow roots as opposed to, say, a sugar maple). Do roots ramify like branches? If i cut back, i will get bifurcation?

4 - the branch work of this tree will also need severe pruning, but i'm unsure how this should be timed in relation to root work (see #1). Should I hold off from pruning the branches until the tree is established in a bonsai pot, or maybe i should do the main branch work first, before i even touch the roots?

If this were your tree and getting it into a bonsai pot was your goal, what would your 2, 3, 4, or 5 year plan be?

Thank you all!

 

[0soyoung]

defoliate at the time of rootwork.

No. Foliage is what powers the root growth to recover from root work. This means you will need to place the tree in shade afterward and sprinkle the foliage in the afternoons when the relative humidity is low. Further it means your root work needs to be conservative. For example, you could knock off the plastic pot, saw off the bottom quarter or third. Likely you can also loosen the roots from the round surface as well and then place it in a wider/shallower container. The key point is that much of the root mass remains undisturbed. At this point in the game, I tend to use landscape bark (medium or small size) with upto an equal part of potting soil to 'back fill'. One can also use their favorite bonsai substrate but this can lead to the nursery soil becoming dry and causing serious problems.

When you can repot in spring 'as buds swell' (spring 2020?) you can completely bare root it to get rid of the nursery soil. Then you will be able to assess what kind of roots you've got. In my experience, the roots of container grown trees just need to be combed out radially and then potted in a wide shallow container of bonsai substrate. Field grown trees, on the other hand, that are usually sold balled and burlapped have a few heavy roots that usually go mostly downward instead of horizontal. One can cut a layering girdle on these before potting - its finer roots will supply the tree with water and minerals and new roots will grow from the top of the girdle (in a year or two, the portions below the girdle can be lopped off.

Should I hold off from pruning the branches until the tree is established in a bonsai pot, or maybe i should do the main branch work first, before i even touch the roots?

I would, though you can do some 'mid-season' pruning/shaping. Come spring, the tree will extend new growth. This will pause somewhere around May. This is a time to prune. Then it will extend growth and again pause around August. This is another time you can prune. It will then weakly extend growth right up to the time of leaf drop in fall. At least Aka shikatatsu sawa behaves this way in my climate. The key point is to let the new growth harden and energize the tree before you prune. Be sparing with your shoot pruning when you've done root work and the tree will stay stronger and more vigorous.

 

[Deleted member 21616]

@0soyoung thank you so so much! I think you answered all of my questions, but generated just one:

It sounds like I might have two options:

I can either do 1: i can do a minor repot as you explain in your first paragraph

or do 2: I can just leave the tree as is for 2019 and wait until spring 2020 and do a bare rooting?

Or would it be preferable to do both option 1 (late spring 2019) and option 2 (bare root spring 2020)?

Thank you!!!

 

[LanceMac10]

Took this......


......did this......



….and put it in that.....


….."wang-chung" the sumbeech…..




























p.s. have plenty of beer handy.....in the moment, it just makes decisions easier!

 

[rockm]

Beginning of the spring as buds swell, pull the tree from the pot. Saw off the bottom two thirds of the root ball. Take a hose at relatively higher (but not power wash strengtJ) wash out the remaining soil. Comb out the remaining roots like Lancemac did. Replant in smaller flatter pot. backfill with bonsai soil.

Heavy top pruning can also be done at the same time. Root work will mitigate the "bleeding" on top from major pruning wounds...

 

[LanceMac10]

pretty much bare-root rinse it all out...look at that perlite!!!!! I use a lil' tub....still alive, by the way. Cut nothing off at repot, if I recall correctly. Straight into full sun...NH sun, so, it's not quite so powerful in spring......

 

[Deleted member 21616]

@LanceMac10 @rockm Thank you both so much! And I really appreciate the photos! @0soyoung sorry for the follow-up question above. I think i have all my answers now!

I will let the tree do it's thing during 2019, and I will do a major root pruning in spring 2020 as buds swell.

I can't believe that I spent a solid 12+ hours researching this through threads, and the three of you just clarified this for me and made this into such a straightforward process in minutes! The reading and research did help too though! Thank you so much!

@LanceMac10 how big is the pot that you planted your 47 inch maple into, and can you tell me more about it? Everybody who i've reached out to about getting a +48" oval pot from koyo (or japan in general) has basically laughed! Apparently i should expect +10k price range, which is not doable for me!

 

[jeanluc83]

a +48" oval pot

That sounds like way oversized for the tree you have pictures. It is hard to say but based on your pictures you will probability end up with a tree much smaller than you think.

I would look into finding a workshop to take the tree to in the spring. Unless the tree was just repotted this year I wouldn't hesitate to repot and cut back the tree spring 2019.

 

[0soyoung]

Everybody who i've reached out to about getting a +48" oval pot from koyo (or japan in general) has basically laughed!

Surely you mean 48 cm (about 19 inches) which is very large. Hollowcreekbonsai.com has some about this size, though you should be looking for one about 12"-14", IMHO; OR make a big grow box for it to live in for the next 5 years, say, before investing big money in a pot for it.

FYI, here is an acer palmatum that was field grown (b&b) that originally was much larger than your aka, now in a 19" oval pot; see that it would fit nicely into a pot a third smaller = about 13 inches. Meanwhile, during development, you may want more room for roots - hence the rec. to build a grow box.

 

[LanceMac10]

Surely you mean 48 cm (about 19 inches) which is very large. Hollowcreekbonsai.com has some about this size, though you should be looking for one about 12"-14", IMHO; OR make a big grow box for it to live in for the next 5 years, say, before investing big money in a pot for it.

FYI, here is an acer palmatum that was field grown (b&b) that originally was much larger than your aka, now in a 19" oval pot; see that it would fit nicely into a pot a third smaller = about 13 inches. Meanwhile, during development, you may want more room for roots - hence the rec. to build a grow box.

…..said in the voice of Peter Griffen……"Oh my god, Star Wars Walker, from the third movie, or was it the sixth....never mind, I just made boom-boom....

….I dig how, in street rod parlance, it's slammed to the floor in that pot! Funky-fresh.

 

[Deleted member 21616]

haha no i did mean inches guys @jeanluc83 @0soyoung

the tree is currently about 40 inches tall (yes over 3 feet tall, or over 100cm)

and the finished tree will be closer to 5 feet tall (60 inches, or 150cm), and probably just as wide.

you can blame @LanceMac10 and his 47 inches (yes, 4 feet) maple (photo attached, I hope you don't mind Lance!). I saw this tree recently and completely fell in love with the idea of having a very big 'bonsai'.

attached photo of Lance's tree taken from here: https://www.bonsainut.com/threads/fall-colors-2016-post-em-up.24932/page-14#post-598812

As I wrote on my main thread (link below), there is a primary trunk and also a strong, low, first branch. When I saw the tree, it immediately reminded me of the general shape of the maples by peter chan or dennis vojtilla (pics attached, the vojtilla pic taken from mybackyardgardenblog).

my main thread: https://www.bonsainut.com/threads/my-maples-in-montreal.33315/page-6

It is more likely that this potted tree will somehow feature in my landscaping (maybe on a very short stand) as opposed to being displayed on my bonsai bench. I'm not exactly sure yet, but I have plenty of time to think about.

@LanceMac10 tell me about your big pot!

 

[LanceMac10]

Semi-unstable Friday measurments resulted in a 36x24 result.....result.


Japanese pot......used Honda? Koyo......lottery winnings!!!

 

[Deleted member 21616]

Thanks @LanceMac10

I guess 36" is much easier to find, but still very big! Can i ask where it came from?

should i be approaching american artists? or is there a cheaper/simpler solution out there? I would still like it to look like a bonsai pot, although I can build a temporary wood pot while i find a buyer for my kidney.

 

[Adair M]

Why are leaving this tree so tall? There’s that long, taperless, branchless section...

This tree would make an ok garden tree, but as is, it’s a poor bonsai prospect. If you want to make a bonsai out of it, chop it to 1/5 it’s height.

There’s a difference between a “tree in a pot”, even if it’s a “bonsai pot”, than a “bonsai”.

If all you want is a potted tree, pot it up however you like. If you want a bonsai, chop it.

At the very least, I would give it a hard cut back this fall, after the leaves have turned, and are about to fall off. That’s the ideal time to cut back to a bud. Be sure to seal the cuts.

 

[Adair M]

haha no i did mean inches guys @jeanluc83 @0soyoung

the tree is currently about 40 inches tall (yes over 3 feet tall, or over 100cm)

and the finished tree will be closer to 5 feet tall (60 inches, or 150cm), and probably just as wide.

you can blame @LanceMac10 and his 47 inches (yes, 4 feet) maple (photo attached, I hope you don't mind Lance!). I saw this tree recently and completely fell in love with the idea of having a very big 'bonsai'.

attached photo of Lance's tree taken from here: https://www.bonsainut.com/threads/fall-colors-2016-post-em-up.24932/page-14#post-598812

As I wrote on my main thread (link below), there is a primary trunk and also a strong, low, first branch. When I saw the tree, it immediately reminded me of the general shape of the maples by peter chan or dennis vojtilla (pics attached, the vojtilla pic taken from mybackyardgardenblog).

my main thread: https://www.bonsainut.com/threads/my-maples-in-montreal.33315/page-6

It is more likely that this potted tree will somehow feature in my landscaping (maybe on a very short stand) as opposed to being displayed on my bonsai bench. I'm not exactly sure yet, but I have plenty of time to think about.

@LanceMac10 tell me about your big pot!

That last tree you attached, that was shown at the Nationals this year. That place on the trunk, just above the first branch, is where the trunk was chopped! The trunk was maybe 3 inches in girth, and took a long time to callous over. That, my friend, is the kind of chop your tree needs.

 

[LanceMac10]

https://bonsaiwest.com/


Think, maybe, $125....bought at sale for a bit less, but you know, Mass tax and all that...so $120-130 sounds right. No way you should ship something this size.


You don't need this size pot, no way. Not even "an all that big" grow box.

 

[LanceMac10]

pretty much bare-root rinse it all out...look at that perlite!!!!! I use a lil' tub....still alive, by the way. Cut nothing off at repot, if I recall correctly. Straight into full sun...NH sun, so, it's not quite so powerful in spring......

View attachment 213968View attachment 213969

@Wilson was 9,666!!!!! F'N AWESOME.....Slayer time.

 

[LanceMac10]

Why are leaving this tree so tall? There’s that long, taperless, branchless section...

This tree would make an ok garden tree, but as is, it’s a poor bonsai prospect. If you want to make a bonsai out of it, chop it to 1/5 it’s height.

There’s a difference between a “tree in a pot”, even if it’s a “bonsai pot”, than a “bonsai”.

If all you want is a potted tree, pot it up however you like. If you want a bonsai, chop it.

At the very least, I would give it a hard cut back this fall, after the leaves have turned, and are about to fall off. That’s the ideal time to cut back to a bud. Be sure to seal the cuts.

no way on the hard cut back, he's in Montreal for goodness sake......and doesn't actually have possession of the tree yet anyways.

 

[Deleted member 21616]

haha thanks @Adair M i appreciate your advice, and if I were planning to make a bonsai in the usual sense I would follow your advice meticulously.

However, i don't intend this to be a 'bonsai' tree in the usual sense.

What I want is a 5 foot tall tree, in a bonsai pot. But i want a 5 foot tree, which is why i bought this tree. it wasn't an accident.

As I mentioned earlier, i'm not looking for impressive trunk taper, or even a remarkable nebari. I simply want a landscape tree, in a pot. Yes, I'll style it, and ramify the branches, etc. but I don't plan on submitting it to Nationals, for example.

I'm looking to the tree of @LanceMac10 (1st pic in my previous post) for inspiration. To me it's 4 foot tall tree in a pot that has been given the bonsai treatment as far as ramification and branch selection goes.

I don't really care for terms, so the "either it's bonsai or it's not bonsai" doesn't really mean anything to me

 

[LanceMac10]

Uhhhhh….. @Adair M know's a hell of a lot more than me, and he's right to call chop.
I didn't develop this tree, came to the garden in upsetting events.....

Cool tree to have in a container and grow, but up north, man....you have to bring it into shelter...and that's a pain to have an appropriate place...