Questions About Growing Pre-Bonsai In Containers

[Tinybird420]

I'm wondering if anyone here could share any resources/personal wisdom about growing pre-bonsai trees in containers. In my experience it's really hard to find information about the pre-bonsai stage in general, let alone for container growing.

Unfortunately I rent so I can't grow out my pre-bonsai in the ground, I have to use containers. On top of that I'm moving to an apartment soon where I'm relegated to the balcony and my mom said the containers could be 12" in diameter max.

I only have pre-bonsai right now. One silver maple tree(Acer saccharinum), two black cherry trees (Prunus serotina), and a roughly 4 month old pin oak tree (Quercus palustris) I collected from the backyard.

My future goal for these trees is to make them into large bonsai. IDK if there's a term for it but I mean the kinda bonsai you see that are like three to four feet tall as their final size.

How can I achieve this in such small containers? I know it's gonna take a very very long time to reach the bonsai stage with this method but the only thing I can think to do is this; grow out the trees in a 5 gallon nursery container, top them/trunk chop when they get too tall, prune 1/3 of the roots whenever they completely fill out the container and plant back into the same container. Rinse and repeat. Will that work? Thanks in advance for your help!

I'm including a pictures of my silver maple tree in the 5 gallon container, sorry it's very hard to see. I'm getting poster board soon so I can take better photos. The 1st picture is from June 8th 2025 so she's grown more since. She's roughly 17 months old and 3 feet tall. I collected her as a tiny seedling growing out of the steps in my front yard July of 2024.

(Also I recognize that many Eastern US native trees struggle with leaf reduction. I personally don't mind large leaves and I'm just really passionate about growing native.)

 

[KateM]

Hi.
Welcome to the forum. You'll find a lot of useful info and advice here.
Personally, I can recommend Nigel Saunder's YouTube channel Bobsai Zone.
He made a choice to grow his bonsai this way - in containers, slowly and patiently.
It works, just takes longer.

 

[Tinybird420]

Hi.
Welcome to the forum. You'll find a lot of useful info and advice here.
Personally, I can recommend Nigel Saunder's YouTube channel Bobsai Zone.
He made a choice to grow his bonsai this way - in containers, slowly and patiently.
It works, just takes longer.

Thanks for the reply! A

nd yeah I love Nigel's channel so much . Pretty much all the trees I've seen of his at least are in bonsai pots though. I haven't really found many channels that show pre-bonsai in growing/nursery pots though. I'll have to do more digging.

 

[KateM]

Yes, lots of us here grow prebonsai in pots, grow boxes, felt pots. Kind of middle point between the ground and bonsai pot.

 

[Tinybird420]

Yes, lots of us here grow prebonsai in pots, grow boxes, felt pots. Kind of middle point between the ground and bonsai pot.

Oh that's great! I actually just learned about grow boxes today and I really wanna try it because silver maple roots prefer to grow far horizontally versus vertically and those boxes look perfect for it.

 

[Kievnstavick]

Hello and welcome to the form. I have a special interest in growing bonsai from seed and I have been working with John Eads to refine my knowledge and techniques.

For all intents and purposes, growing any plant in a confined environment will slow the overall growth down. When thinking about this in terms of bonsai (and pre-bonsai specifically), you have to make the final determination of what results you are looking for in terms of Speed vs Control.

For your (future) limitations, the best practice would be to perform a repotting operation every couple of years (Think about every other year or every 3 years) in order to establish a good nebari. That should be your first focus as it can be hard to correct later down the road. The basic operation would be to remove the tree from the pot, clean out the roots, prune the roots for growth management, laying the roots flat and trimming them to fit into its current and/or future pot.

The idea is to create a great nebari while you are still working on other major operations and to fix any unsightly or obvious root design issues. Then the roots are trimmed to fit into the growing container while still having room to grow outwards so that they don't immediately dive down the sides of the container once the start growing again.

You'll then want to put it either back into the same pot, increase, or decrease the pot size depending on what you think is needed for the next growing cycle. For instance, discovering the tree only has roots on one side would probably be a decrease or same size situation because you want to let the tree have time to throw roots out on that one side. Increasing the pot size would only give the system more gas to go and thus your one sided still will probably stay one sided with thicker roots. If you have okay roots, but the branch structure is setting nicely then you'll want to start slowing it down si you don't loose the structure. The roots will eventually catch up.

Fill the pot up with your substrate. Place your tree in the pot with the roots laying flat/arranged, then bury the roots. Your chosen substrate medium will be ultimately up to you and how often you'd want to water the trees. Like potting soil, coconut coir and pumice, or a bonsai substrate.

You'll want to be shaping your tree as best as you can given your vision and options. Going with John Eads' method, we shape, train, and prune the saplings from year two and beyond. This gives us a large amount of control of the direction the tree is heading rather then just grow the tree out then chopping it, then working in the structure.

 

[Kievnstavick]

Oh that's great! I actually just learned about grow boxes today and I really wanna try it because silver maple roots prefer to grow far horizontally versus vertically and those boxes look perfect for it.

Anderson Flats work great as a stop-gap between grow boxes and bonsai pots.

 

[Tinybird420]

Hello and welcome to the form. I have a special interest in growing bonsai from seed and I have been working with John Eads to refine my knowledge and techniques.

For all intents and purposes, growing any plant in a confined environment will slow the overall growth down. When thinking about this in terms of bonsai (and pre-bonsai specifically), you have to make the final determination of what results you are looking for in terms of Speed vs Control.

For your (future) limitations, the best practice would be to perform a repotting operation every couple of years (Think about every other year or every 3 years) in order to establish a good nebari. That should be your first focus as it can be hard to correct later down the road. The basic operation would be to remove the tree from the pot, clean out the roots, prune the roots for growth management, laying the roots flat and trimming them to fit into its current and/or future pot.

The idea is to create a great nebari while you are still working on other major operations and to fix any unsightly or obvious root design issues. Then the roots are trimmed to fit into the growing container while still having room to grow outwards so that they don't immediately dive down the sides of the container once the start growing again.

You'll then want to put it either back into the same pot, increase, or decrease the pot size depending on what you think is needed for the next growing cycle. For instance, discovering the tree only has roots on one side would probably be a decrease or same size situation because you want to let the tree have time to throw roots out on that one side. Increasing the pot size would only give the system more gas to go and thus your one sided still will probably stay one sided with thicker roots. If you have okay roots, but the branch structure is setting nicely then you'll want to start slowing it down si you don't loose the structure. The roots will eventually catch up.

Fill the pot up with your substrate. Place your tree in the pot with the roots laying flat/arranged, then bury the roots. Your chosen substrate medium will be ultimately up to you and how often you'd want to water the trees. Like potting soil, coconut coir and pumice, or a bonsai substrate.

You'll want to be shaping your tree as best as you can given your vision and options. Going with John Eads' method, we shape, train, and prune the saplings from year two and beyond. This gives us a large amount of control of the direction the tree is heading rather then just grow the tree out then chopping it, then working in the structure.

Thank you so much for all of the information. I'll look up John Ead too in a bit too ty.

I also forgot to mention, I have chronic pain in my fingers so I can't do wiring unfortunately. Just hurts my fingers too much. So I wanna pretty much exclusively do clip n grow or just any non wiring technique. So when my silver maple tree for example gets too tall and I need to reduce it, can I cut back to a branch lower on the tree? (I'm assuming that branch would then become the new leader?) Or is there a better technique? I'm kinda stumped on what to do when I hit that point every few years. I'm not sure how tall the ceiling of the balcony is where I'm moving to but I assume I'll have to reduce it in height every few years somehow.

EDIT: I just realized, should I be cutting it back little by little during each growing season in their pre-bonsai stage? Like is that better than one big prune less often?

 

[Kievnstavick]

Thank you so much for all of the information. I'll look up John Ead too in a bit too ty.

I also forgot to mention, I have chronic pain in my fingers so I can't do wiring unfortunately. Just hurts my fingers too much. So I wanna pretty much exclusively do clip n grow or just any non wiring technique. So when my silver maple tree for example gets too tall and I need to reduce it, can I cut back to a branch lower on the tree? (I'm assuming that branch would then become the new leader?) Or is there a better technique? I'm kinda stumped on what to do when I hit that point every few years. I'm not sure how tall the ceiling of the balcony is where I'm moving to but I assume I'll have to reduce it in height every few years somehow.

EDIT: I just realized, should I be cutting it back little by little during each growing season in their pre-bonsai stage? Like is that better than one big prune less often?

I don't know if John has his methods written in a blog somewhere, but he is a very open guy and willing to share his knowledge. He is on Bnut sometimes.

The chronic pain does limit the options a bit. At least it would make small dynamic trees harder to make believable.

on the topic of cut backs, you will want to try and manage the growth as best as possible. For trunk chops, you will want to already have a branch ready to take over as the new leader (postioned vertically) otherwise you would have to wire it up. The tree might raise it on its own or it maybe just leave it as it currently is. For chops, you want the next sized branch to take over to be about half of the chops thickness. That helps reduce dieback as the cells/veins reorentate to the new leader. The two instances for chopping would be you achieved the thickness required or it gets too tall. If it gets too tall and you need to chop it, cut it back to a height where the tree has enough vertical height left to grow for 1-2 years before another chop.

You will also want to remove any leaves and branches of any unwanted growth. Let's say you have decided some lower branch was to become the new leader/transition point for taper, anything above that is now considered sacrificial. By removing the unwanted growth, it let's the tree put more energy into the lower limbs, trunk girth, and/or height. You would want to leave a couple of leaves only at the very top so that the tree still grows taller. See the attached image of one of my alders back in late fall. Everything above the lower vertical branches is considered sacrificial in order to increase the diameter of the lower trunk. One the branches get thick enough, I'll chop the trunk. For that entire length of trunk, I only have three leaves at the very top until those vertical branches.



You will probably be performing height chops every couple of years to keep the tree in check for your space constraints.

Another option is to do the slow method of clip N grow for a trunk line. I don't have as much experience for that method of trunk development, but to get the diameter to make a convincing 3 foot tree it would probably be a very long time and I can imagine a bit if wasted effort as your design intentions change over the years where as trunk chopping is more of a can't go back once it is cut.

I would say you should be cutting back the lower branches little by little each growing season to create fantastic ramifications earlier and close to the trunk. It is not necessary, but it is a better method in my opinion then chopping a branch (it also reduces the chance of large unsightly scars). There maybe times where you left a branch run in order to build better taper and proportions.

Just remember that there are many ways to go about designing a Bonsai. Nothing is inherently wrong as long as it is not detrimental to the tree. There is a balancing act of fast and controlled methods, Hard chops and clipping.

Expirement with things and find what works best for you and your location.

 

[Shibui]

So I wanna pretty much exclusively do clip n grow or just any non wiring technique. So when my silver maple tree for example gets too tall and I need to reduce it, can I cut back to a branch lower on the tree? (I'm assuming that branch would then become the new leader?) Or is there a better technique? I'm kinda stumped on what to do when I hit that point every few years. I'm not sure how tall the ceiling of the balcony is where I'm moving to but I assume I'll have to reduce it in height every few years somehow.

This is how I develop a lot of trees. Grow and then chop. You can chop back to an existing branch if there's one growing in the right direction at the right height. Otherwise just chop the trunk/branch where you want the bend/new leader and cross fingers (metaphorically if it's too hard to cross fingers for real)
Letting a trunk get real tall will give maximum trunk thickening but you'll need to temper that knowing the bigger it gets the bigger the cut when you chop and larger cuts take longer to heal. Sometimes it's better to sacrifice some thickening for the sake of smaller cuts that will heal a bit quicker.

I just realized, should I be cutting it back little by little during each growing season in their pre-bonsai stage? Like is that better than one big prune less often?

Regular trimming removes leaves which limits photosynthesis which then limits trunk thickening. I definitely get more thickening by pruning less and allowing plenty of growth.

My future goal for these trees is to make them into large bonsai. IDK if there's a term for it but I mean the kinda bonsai you see that are like three to four feet tall as their final size.

Need to be aware that larger bonsai require larger pots = cost. Check some pot prices to see if that's within your planned budget before creating big trees.
Also consider weight of larger bonsai. They will need to be moved regularly - turned weekly to get light on all sides of the tree so it grows all round, moved to clean up around the pots, moved or turned to allow trimming all round, etc.
Even larger bonsai need to be repotted every few years. This involves moving pot and all to a spot you can work, lift the tree out of the pot and support it while removing some or all soil mix, trimming the roots, repositioning the tree and supporting it while replacing fresh soil mix around the roots then move the whole thing back to it's normal location.
I'm gradually downsizing my bonsai because the logistics of handling larger, heavier trees.

Another factor to consider with larger bonsai is the time factor. No problem while the trees are developing. Trimming takes maybe 10 minutes. As the tree develops branches and increased ramification the time increases. Trimming some of my older trees now takes 2-3 hours. I can sometimes spend a full day doing detailed wiring and trimming now.

How can I achieve this in such small containers? I know it's gonna take a very very long time to reach the bonsai stage with this method but the only thing I can think to do is this; grow out the trees in a 5 gallon nursery container, top them/trunk chop when they get too tall, prune 1/3 of the roots whenever they completely fill out the container and plant back into the same container. Rinse and repeat. Will that work?

Interestingly, trees seem to grow more in the season after root pruning. More room for new roots to grow, more spaces in the soil, more available nutrients all contribute to increased growth rates V the same tree in the same pot for several years so don't be frightened to repot regularly.
Upsizing containers too quick can cause problems. Move up 2 or 3 sizes each year as the root system starts to fill available space.
Generally, the larger the container, the more growth you can get. Shallow containers are popular to train the roots but deeper containers have the advantage of slowing daily moisture and temperature swings which can mean better growth rates. Roots are easily trained to flat with root pruning once you get over the natural reluctance to cut roots. If you are limited to container diameters, maybe deeper pots and judicious root pruning will give better growth rates.

 

[leatherback]

I have a few videos on my channel of trees being grown out in pots. And I made a video explaining what the benefits are. Might be helpfull.

Some suggestions. Beware of the rabbithole.

and eg:

 

[rockm]

I'm wondering if anyone here could share any resources/personal wisdom about growing pre-bonsai trees in containers. In my experience it's really hard to find information about the pre-bonsai stage in general, let alone for container growing.

Unfortunately I rent so I can't grow out my pre-bonsai in the ground, I have to use containers. On top of that I'm moving to an apartment soon where I'm relegated to the balcony and my mom said the containers could be 12" in diameter max.

I only have pre-bonsai right now. One silver maple tree(Acer saccharinum), two black cherry trees (Prunus serotina), and a roughly 4 month old pin oak tree (Quercus palustris) I collected from the backyard.

My future goal for these trees is to make them into large bonsai. IDK if there's a term for it but I mean the kinda bonsai you see that are like three to four feet tall as their final size.

How can I achieve this in such small containers? I know it's gonna take a very very long time to reach the bonsai stage with this method but the only thing I can think to do is this; grow out the trees in a 5 gallon nursery container, top them/trunk chop when they get too tall, prune 1/3 of the roots whenever they completely fill out the container and plant back into the same container. Rinse and repeat. Will that work? Thanks in advance for your help!

I'm including a pictures of my silver maple tree in the 5 gallon container, sorry it's very hard to see. I'm getting poster board soon so I can take better photos. The 1st picture is from June 8th 2025 so she's grown more since. She's roughly 17 months old and 3 feet tall. I collected her as a tiny seedling growing out of the steps in my front yard July of 2024.

(Also I recognize that many Eastern US native trees struggle with leaf reduction. I personally don't mind large leaves and I'm just really passionate about growing native.)

"My future goal for these trees is to make them into large bonsai. IDK if there's a term for it but I mean the kinda bonsai you see that are like three to four feet tall as their final size."

This will not happen, sorry. Sorry, should say won't happen in your lifetime. It is a misconception that bonsai are started as seeds. They are but those seeds are mostly not placed in containers and grown on to produce bonsai.

Large bonsai are not "grown up" from smaller stock. They are "cut down" from larger trees mostly grown in the ground. As said, containers limit growth, which slows down development--this is why bonsai is bonsai--Once placed in a container, things slow down. Tree become more static. Large bonsai (and smaller ones too) are generally developed outside of a container initially and placed in them to REFINE them. The "Heavy lifting" of trunk and initial branch development is done in ground for the most part.

 

[Tinybird420]

Anderson Flats work great as a stop-gap between grow boxes and bonsai pots.

These look really good thank you!

I don't know if John has his methods written in a blog somewhere, but he is a very open guy and willing to share his knowledge. He is on Bnut sometimes.

The chronic pain does limit the options a bit. At least it would make small dynamic trees harder to make believable.

on the topic of cut backs, you will want to try and manage the growth as best as possible. For trunk chops, you will want to already have a branch ready to take over as the new leader (postioned vertically) otherwise you would have to wire it up. The tree might raise it on its own or it maybe just leave it as it currently is. For chops, you want the next sized branch to take over to be about half of the chops thickness. That helps reduce dieback as the cells/veins reorentate to the new leader. The two instances for chopping would be you achieved the thickness required or it gets too tall. If it gets too tall and you need to chop it, cut it back to a height where the tree has enough vertical height left to grow for 1-2 years before another chop.

You will also want to remove any leaves and branches of any unwanted growth. Let's say you have decided some lower branch was to become the new leader/transition point for taper, anything above that is now considered sacrificial. By removing the unwanted growth, it let's the tree put more energy into the lower limbs, trunk girth, and/or height. You would want to leave a couple of leaves only at the very top so that the tree still grows taller. See the attached image of one of my alders back in late fall. Everything above the lower vertical branches is considered sacrificial in order to increase the diameter of the lower trunk. One the branches get thick enough, I'll chop the trunk. For that entire length of trunk, I only have three leaves at the very top until those vertical branches.

View attachment 608369

You will probably be performing height chops every couple of years to keep the tree in check for your space constraints.

Another option is to do the slow method of clip N grow for a trunk line. I don't have as much experience for that method of trunk development, but to get the diameter to make a convincing 3 foot tree it would probably be a very long time and I can imagine a bit if wasted effort as your design intentions change over the years where as trunk chopping is more of a can't go back once it is cut.

I would say you should be cutting back the lower branches little by little each growing season to create fantastic ramifications earlier and close to the trunk. It is not necessary, but it is a better method in my opinion then chopping a branch (it also reduces the chance of large unsightly scars). There maybe times where you left a branch run in order to build better taper and proportions.

Just remember that there are many ways to go about designing a Bonsai. Nothing is inherently wrong as long as it is not detrimental to the tree. There is a balancing act of fast and controlled methods, Hard chops and clipping.

Expirement with things and find what works best for you and your location.

This was so helpful thank you so much to .

 

[Tinybird420]

This is how I develop a lot of trees. Grow and then chop. You can chop back to an existing branch if there's one growing in the right direction at the right height. Otherwise just chop the trunk/branch where you want the bend/new leader and cross fingers (metaphorically if it's too hard to cross fingers for real)
Letting a trunk get real tall will give maximum trunk thickening but you'll need to temper that knowing the bigger it gets the bigger the cut when you chop and larger cuts take longer to heal. Sometimes it's better to sacrifice some thickening for the sake of smaller cuts that will heal a bit quicker.


Regular trimming removes leaves which limits photosynthesis which then limits trunk thickening. I definitely get more thickening by pruning less and allowing plenty of growth.


Need to be aware that larger bonsai require larger pots = cost. Check some pot prices to see if that's within your planned budget before creating big trees.
Also consider weight of larger bonsai. They will need to be moved regularly - turned weekly to get light on all sides of the tree so it grows all round, moved to clean up around the pots, moved or turned to allow trimming all round, etc.
Even larger bonsai need to be repotted every few years. This involves moving pot and all to a spot you can work, lift the tree out of the pot and support it while removing some or all soil mix, trimming the roots, repositioning the tree and supporting it while replacing fresh soil mix around the roots then move the whole thing back to it's normal location.
I'm gradually downsizing my bonsai because the logistics of handling larger, heavier trees.

Another factor to consider with larger bonsai is the time factor. No problem while the trees are developing. Trimming takes maybe 10 minutes. As the tree develops branches and increased ramification the time increases. Trimming some of my older trees now takes 2-3 hours. I can sometimes spend a full day doing detailed wiring and trimming now.


Interestingly, trees seem to grow more in the season after root pruning. More room for new roots to grow, more spaces in the soil, more available nutrients all contribute to increased growth rates V the same tree in the same pot for several years so don't be frightened to repot regularly.
Upsizing containers too quick can cause problems. Move up 2 or 3 sizes each year as the root system starts to fill available space.
Generally, the larger the container, the more growth you can get. Shallow containers are popular to train the roots but deeper containers have the advantage of slowing daily moisture and temperature swings which can mean better growth rates. Roots are easily trained to flat with root pruning once you get over the natural reluctance to cut roots. If you are limited to container diameters, maybe deeper pots and judicious root pruning will give better growth rates.

Thanks for the information!

And yeah I really do love deeper pots tbh. Because it means I don't have to water nearly as often basically. We're getting pretty bad heatwaves in Ohio and I've heard some people say that during a heatwave they need to water their tree that's in a bonsai pot like 4 times a day lol. That would be very exhausting for me so only have to water once a day or less (for now) is really nice.

 

[Tinybird420]

"My future goal for these trees is to make them into large bonsai. IDK if there's a term for it but I mean the kinda bonsai you see that are like three to four feet tall as their final size."

This will not happen, sorry. Sorry, should say won't happen in your lifetime. It is a misconception that bonsai are started as seeds. They are but those seeds are mostly not placed in containers and grown on to produce bonsai.

Large bonsai are not "grown up" from smaller stock. They are "cut down" from larger trees mostly grown in the ground. As said, containers limit growth, which slows down development--this is why bonsai is bonsai--Once placed in a container, things slow down. Tree become more static. Large bonsai (and smaller ones too) are generally developed outside of a container initially and placed in them to REFINE them. The "Heavy lifting" of trunk and initial branch development is done in ground for the most part.

You're probably right. I enjoy the pre-bonsai stage a lot anyways as it's a bit more hands off than the bonsai stage. I'm limited to containers so I'm just gonna get my trees as big as I can and see how things go.

 

[rockm]

You're probably right. I enjoy the pre-bonsai stage a lot anyways as it's a bit more hands off than the bonsai stage. I'm limited to containers so I'm just gonna get my trees as big as I can and see how things go.

If you want bigger bonsai START WITH BIGGER STOCK Instead of looking at seedlings with 1/4 inch trunks. Look at ALREADY CONTAINERIZED trees at the nursery. Depending on species many can be quickly adapted for use as bonsai.

Personally I’ve used 20’ containerized. Nursery bald Cypress. I chop the trunk to two or three feet and work from there. Such fast growing trees like BC and elm can be reduced significantly and the remaining trunk is used as the scaffolding to build new branches and finally a bonsai from. Many bonsai have begun with larger containerized nursery trees

 

[MrFancyPlants]

It has already been mentioned, but Anderson flats are a great way to get “growing in the ground” type growth, while not actually growing in the ground. It can really speed development if you are targeting larger trees. I have shared flats with multiple trees too, though some might frown upon. Grow bags are popular too.

If you have a passion for native plants, try some Tsuga canadensis or eastern hemlock. I think they are my favorite species, though not suitable for my climate since I moved South.
The leaves are small enough you could target a shohin or smaller tree.

 

[Michael P]

I don't have much to add to the excellent advice already given, but wanted to wish you good luck! The limitations you have are very similar to those of older bonsai hobbyists so look to them for advice. Before copper wire became readily available after WW2, almost all bonsai were developed by grow-and-clip and this is still a common practice for some traditions of penjing.

 

[Tinybird420]

It has already been mentioned, but Anderson flats are a great way to get “growing in the ground” type growth, while not actually growing in the ground. It can really speed development if you are targeting larger trees. I have shared flats with multiple trees too, though some might frown upon. Grow bags are popular too.

If you have a passion for native plants, try some Tsuga canadensis or eastern hemlock. I think they are my favorite species, though not suitable for my climate since I moved South.
The leaves are small enough you could target a shohin or smaller tree.

I really gotta try those Anderson flats out. They sound really good.

Also thank you so much for bringing up Tsuga canadensis. That is such a GOATed tree and I really wanna grow one. It makes me sad every time I think about that tree because a long ass time ago there were MASSIVE ones in the Eastern US on par with the huge redwoods in the West, but most were cut down .

 

[Tinybird420]

I don't have much to add to the excellent advice already given, but wanted to wish you good luck! The limitations you have are very similar to those of older bonsai hobbyists so look to them for advice. Before copper wire became readily available after WW2, almost all bonsai were developed by grow-and-clip and this is still a common practice for some traditions of penjing.

Thank you .