Colanders

[Mitch_28]

I'm looking at putting a few trees in colanders to advance their structure. Is now a good time of year to do this, being autumn and having the days still warm south of Sydney.
With looking through the forum I've also seen different ways of using them. I was just planning on potting my tree into the colander and burying the whole thing in the garden. Is this the best way to do it and do I dig it out each year to chop roots back on outside of colander or just leave for numerous years to it's own devices while keeping above ground growth in check? Cheers Mitch

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[shibui]

I haven't used colanders for bonsai. It appears the idea was first promoted for growing pines which enjoy drier roots but has now been extended to other species and ground growing. I have seen lots of people talking about this but only a couple publishing results. Now we are seeing all sorts of people making all sorts of claims for many different aspects of growing in colanders, many without any basis and probably a result of misinterpreting someone else.
You could try an Ausbonsai search for RayM to find some of his posts about colander growing. I remember him showing some good results with wisteria.

I prefer to grow my trees in the ground using regular root pruning to achieve good root systems. If I see and prune each root individually I can tailor the pruning to achieve a better result. No telling what is going on inside a colander until the end.
I'm not sure whether the plastic in a colander is rigid enough to effectively root prune any roots that emerge and start to thicken but will be interested to see any results.

[MJL]

Ok - I'm taking GavinG's advice and I'll try a non-self-depracating post; with one caveat to start - I am not a horticulturalist.

Colander growing was the most discussed 'topic' in a presentation I recently gave at the Yarra Valley Bonsai Society. A small part of that presentation discussed my desire to start to grow more plants in colanders - while I had not done that yet, I wanted to try. Boy - did that create some debate but all is good nature.

Here's a summary of the rather 'vibrant' discussion:

Some experienced growers questioned why anyone would grow a plant in a colander in the ground. Some quite passionately saying it was unnecessary. Just grow a bloody plant in the ground and dig it up each year or two. Why complicate the concept

A horticulturalist (not experienced in bonsai but very knowledgable) entered the fray and while I am paraphrasing, he noted:
Some commercial growers use fabric grow bags. Grow bags have numerous benefits including - less chance of roots circling like they may do if left in a plastic pot, better aeration, air pruning, finer roots ... to name a few benefits. It was suggested that colander growing was not a dis-similar idea and perhaps that was the attraction.

Other experienced members noted that while colanders were not needed per se they did provide a safer/easier way for inexperienced growers to learn to grow in the ground - in that they could raise the colander on an annual basis, trim roots around the outside of the colander and then repeat; effectively containing the root ball, refining roots and still getting the benefits of faster growth than if not ground grown. That made sense to me.

So what does that all mean. Well... I retained my desire to try. I will be growing some pine seedlings in colanders and some just straight in the ground and some in plastic 'flat orchid pots' - and over the years we'll see what happens.

I'll do my best to record the results here.

Cheers,

Mark

[robb63]

Hi Mitch
When you say advance the trees structure I assume you mean thickening and maximising growth.
Colanders I have found troublesome. Most are not UV resistant and crumble when lifted unless buried completely.
I found no great advantage when lifting a colandered tree to say a ground grown one.
Though I only tried colanders for 2years that was long enough to switch me to orchid pots.
Orchid pots can sit on your garden bed and the roots escape as they please through all the holes.
You can bury the pots if you like but I prefer to minimise the digging part so sit mine on the surface.
If you have enough space at home I found it's good to try a few different ways of growing.
Colanders, pots, in ground or grow boxes. So you see what works best for you.

[Tambrand]

I use what we call a trough for growing trunks.
I use a colander, it is covered with soil and has no contact with U.V.
When I dig up, I leave the tree in the colander to regrow the fine feeder
roots and get the air-pruning [ see Air-Pot / Scotland on Youtube ]
effect.

I can then remove the thick roots safely and have a good many fine roots
to keep the tree alive. Safety Blanket.
Laters.
Tambrand

When I lived in Lafayette, Louisiana, I collected 3 seedlings from a
mature Celtis l. [ Hackberry ] in 1980.
They are dear to me and so I take my time with them.
I use a refridgerator to simulate winter.

With this tree, the mother died, but a root shot up and the tree continues on.
After trunk growth, I work on branchlet refinement in an oversized bonsai
pot.

hack col.jpg

The tree going for refinement - branchlets

hac.jpg

My growing trough.

plant trough.jpg

Refinement of branchlets - in leaf

hackb 2018.jpg

[Beano]

I’m having varying success and failure using colander in ground method. Almost certainly some do poorly because of the very different soil type, as my grow bed has heavy clay and just holds water differently. The swamp cypress loves it but the eucalyptus doesn’t really like having its roots disturbed when it’s unearthed from the grow bed. Ginkgo doesn’t do much anyway so probably hasn’t made much difference to it. My huge fig cutting has done pretty well but I thought it would have progressed more.

My grow bed could get more sun so that may be a factor too. The hawthorn did ok but didn’t thicken much, just sent fat green shoots in many directions. The branches thicken but not the trunk.

[Rory]

Orchid pots can sit on your garden bed and the roots escape as they please through all the holes.
You can bury the pots if you like but I prefer to minimise the digging part so sit mine on the surface.

What he said.

I would only add that its best to remove the roots sooner then later (6 months to 9 months), to allow the roots inside the orchid pot to stay healthy and not be by-passed by stronger dominant ground roots.

I have much more experience with natives, but personally I don't really see the great advantage of ground growing native material anymore.
I prefer a fast draining mix and let the roots go to town inside a porportionately large orchid pot and be able to monitor the roots more effectively.

[Keels]

i got into colanders about 2 years ago. I grow elms and afew maples in colanders that i have planted in the ground. I use the colanders for different reasons. First reason is that i only rent the house i am in. When i have to move in the next year or so i will hopefully be able to remove the trees still in the colanders without much hassle. The other reason is i wanted to see if it made a difference by allowing the trees to grow in colanders in the ground and only trimming the roots outside of the colander yearly. Now two years on i dont really see any benefit but the fact that when i have to move house it'll be easier to dig the colander out and it shouldn't really impact the trees if we move in winter or summer etc.

[Mitch_28]

Thanks for all your advice and information.
I am definitely looking to maximise growth hence looking for ideas and methods to do so.
The main reason I thought colanders might work for me is because I want to advance a couple of young cedars that I have and from my research read they don't enjoy too much root work. I was worried if I buried them directly in a bed the roots could take off and my chances of long-term success may decrease. I think maybe I'll put one in a colander or orchid pot and one direct and see what happens.
Can anyone tell me if cedars will sink a big tap root and if maybe it's worth burying a paver at a depth under it to deter it going too deep. Or just dig it out each year or so to keep it in check?

Thanks again legends!


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[shibui]

Trees don't actually grow a tap root the way most of us think. Different species have slightly different root patterns but generally roots grow in all different directions. Some shallow laterals that access lots of nutrients, some deeper ones that provide water in dry times and get hold of deeper nutrients. The vast majority of roots are shallow. Next time you see a tree blown over after a storm, take some time to check the root system and you will see what I mean.
However, even 'shallow' roots are too deep for bonsai. Putting something under the tree may not actually make much difference. A root that wants to go deep will hit the tile, grow across it then dive down as soon as it reaches the edge. Have you achieved anything? Good root pruning achieves better results than simply putting a block under the tree.
Cedars grow very slowly, even in the ground so I doubt you will be digging them each year. That's for faster growing species like maples. I have not grown cedar in the grow beds but I do grow Black pines and shimpaku which are both relatively slow. Both are generally left 3-5 years before digging and root pruning. I do have occasional losses but take that as part of the process just as not every tree you plant in the grow bed will become a great bonsai. There is always going to be failures in any venture and when working with living things, failure rates are even higher. All we can do is minimise the numbers that don't work out.

[Mitch_28]

Trees don't actually grow a tap root the way most of us think. Different species have slightly different root patterns but generally roots grow in all different directions. Some shallow laterals that access lots of nutrients, some deeper ones that provide water in dry times and get hold of deeper nutrients. The vast majority of roots are shallow. Next time you see a tree blown over after a storm, take some time to check the root system and you will see what I mean.
However, even 'shallow' roots are too deep for bonsai. Putting something under the tree may not actually make much difference. A root that wants to go deep will hit the tile, grow across it then dive down as soon as it reaches the edge. Have you achieved anything? Good root pruning achieves better results than simply putting a block under the tree.
Cedars grow very slowly, even in the ground so I doubt you will be digging them each year. That's for faster growing species like maples. I have not grown cedar in the grow beds but I do grow Black pines and shimpaku which are both relatively slow. Both are generally left 3-5 years before digging and root pruning. I do have occasional losses but take that as part of the process just as not every tree you plant in the grow bed will become a great bonsai. There is always going to be failures in any venture and when working with living things, failure rates are even higher. All we can do is minimise the numbers that don't work out.

As always, thank you for taking the time to share your knowledge.
All valid points that I will take on board.

I think I just need to worry less, do more, be patient, observe & learn. Knowledge and experience comes with actions and time, both of which I've just realised I need more of.

Mitch


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[pureheart]

Trees don't actually grow a tap root the way most of us think. Different species have slightly different root patterns but generally roots grow in all different directions. Some shallow laterals that access lots of nutrients, some deeper ones that provide water in dry times and get hold of deeper nutrients. The vast majority of roots are shallow. Next time you see a tree blown over after a storm, take some time to check the root system and you will see what I mean.
However, even 'shallow' roots are too deep for bonsai. Putting something under the tree may not actually make much difference. A root that wants to go deep will hit the tile, grow across it then dive down as soon as it reaches the edge. Have you achieved anything? Good root pruning achieves better results than simply putting a block under the tree.
Cedars grow very slowly, even in the ground so I doubt you will be digging them each year. That's for faster growing species like maples. I have not grown cedar in the grow beds but I do grow Black pines and shimpaku which are both relatively slow. Both are generally left 3-5 years before digging and root pruning. I do have occasional losses but take that as part of the process just as not every tree you plant in the grow bed will become a great bonsai. There is always going to be failures in any venture and when working with living things, failure rates are even higher. All we can do is minimise the numbers that don't work out.

Thanks so much for sharing


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