Next step for seedlings.

[bluejayflies]

I'm very new to bonsai, but not to horticulture. I have two seedlings that I am going to attempt to bonsai. I'm trying to determine when to move them to bonsai pots. And if so what time of year is best. Both seedlings are currently in potting soil.

Seedling 1:
Seedling one is a Cutleaf Japanese Maple that is a seeding that I found under my Japanese Maple this spring. I moved it to a pot and this thing has gone nuts. It has grown a single stem that is 18 inches tall. Should I just top this at my desired height and let it grow another year in the pot or should I pull it, trim the roots and put it in bonsai soil?

Seeding 2:
Seedling two is not really a seedling. It's at least a year old when I dug it in early spring. I potted it and it has done well. Should I repot this one, and trim roots? Or let it go another year?

I need to repot both of these trees as they are in the same large container. And I don't want the roots to intertwine. Do I just move them to separate containers and not mess with the roots and let them grow another year. Or should I get them in bonsai soil so it's easier to deal with the roots.

Normally I would repot or transplant plants in the fall or early spring. What do you guys recommend for these outdoor deciduous trees?

Thanks for any input.

 

[ShadyStump]

Welcome to the nut house!

You really don't want to put anything in a bonsai pot until you're ready for the trunk to stop thickening up. Putting it in a container that will let it grow, but train the roots horizontally is a good idea, though.
Some of us build wooden boxes for this, some folks recommend perforated containers like pond baskets or even dollar store collenders. If you have an oversized bonsai pot, bigger than what you feel your finished product will be, that can work. Really, whatever works.
The idea is to get the roots growing out horizontally so that, 1: you don't have to cut half of them out to get the tree into a shallow bonsai pot eventually, and 2: to help build good looking nebari, the surface roots you find on many mature trees. There are miriad options for decent training pots, that all depend on your personal preference, how you plan on treating the root system, and the tree species. Some people plant their trees back in the ground to allow them to grow out as quickly as possible.
Separate your two trees as soon as you have something to put them in. If you know horticulture already, you know what seasons work.

Chop the trunk once your ready to get more branching, in the appropriate season for pruning.

BTW, you'll get asked about your location routinely around here, as your climate will affect any answers you get to any questions, so go ahead and add it to your profile now. Heck, something as generalized as a continent and USDA growing zone will shut most people up.

 

[Potawatomi13]

You really don't want to put anything in a bonsai pot until you're ready for the trunk to stop thickening up. Putting it in a container that will let it grow, but train the roots horizontally is a good idea, though.
Some of us build wooden boxes for this

Very strongly recommend this strategy.

BTW, you'll get asked about your location routinely around here, as your climate will affect any answers you get to any questions, so go ahead and add it to your profile now.

Much needed info here.

 

[Shibui]

There are so many variables in these questions it is only possible to give very general answers.
So much depends on what you want to achieve in future - trunk size, quality of bonsai, how long you want to spend growing them and so much more. Even then there's proably a handful of different approaches that could get you to the same point.

Just a couple of things that stand out from the original post.

Should I just top this at my desired height and let it grow another year

Trees always grow up and out after a chop. Chopping at desired height will inevitably result in a larger tree as it grows back. Always make initial chops somewhere around 1/3 of final height or at first branch height to allow for trunk taper, branching, bends in trunk and future growth to final height.

Seedling one is a Cutleaf Japanese Maple that is a seeding that I found under my Japanese Maple this spring

I'm very surprised to hear of a cutleaf JM that's growing strong. Usually very weak when growing on their own roots so would love to see photo of that one.

Normally I would repot or transplant plants in the fall or early spring. What do you guys recommend for these outdoor deciduous trees?

Early spring transplant is definitely recommended for most deciduous sp. Roots entwining is not such an issue for bonsai growers. We get accustomed to cutting roots and the trees just grow more roots so there's no problem waiting for next spring. There's little difference in dealing with roots in potting soil, garden soil or bonsai soil. We still cut roots the same and can comb out any remaining soil that is not good. Bonsai soil is more about good drainage for shallow pots, not so much about roots or how they grow.

You could trim either or both now if you like but that will also slow growth and trunk thickening or you can just let them grow free for a year or more before doing anything.

 

[bluejayflies]

Great replies, and good info.

I am in USDA 7b. I did mean to put this in the op.

I think fast growing trunk diameter is something we all like to see. If I were to repot now, should I trim the roots to encourage horizontal root growth, to encourage faster trunk diameter? Or will it not really make a difference if I root trim this year or next.

I do like the idea of building training boxes. As I can make my horizontal roots as big as I like.

I'm very surprised to hear of a cutleaf JM that's growing strong. Usually very weak when growing on their own roots so would love to see photo of that one

I am out of town now. But will post when I return. This is the only seeding I have ever seen from this tree in the 10+ years that I have had it.

 

[Diggumsmack2]

What species was seedling #2?

 

[bluejayflies]

What species was seedling #2?

I guess I forgot to mention that. It's an Eastern Redbud

 

[BrightsideB]

If you want to do stuff from seed. Forests are a good option and fun. As well as doing clumps. If you want to do bonsai. Those two seedlings only are going to be a slow go. And eastern bud is going to be hard to really work with. Buying nursery stock you can afford is a good option as well. Understanding the times of year to do specific work to tree is pretty critical.

 

[BonsaiNaga13]

My recomendacion is collect more seeds so you have more oppertunities for growth. My experience with Ap disectum is they grow well first season and die over winter regardless of in pot or in ground, bonsai soil or organic potting soil but you may have some luck. Most ap disectum are grafted on to hartier root stock to solve that issue. Just My 2 cents.

Also its seed collection time for most trees

 

[BeepBeepBonsaiSheep]

Get more seeds! I planted 20 mesquite seeds and have lost a few since planting them July 2021. Missed watering or a little too hard on the fertilizer. Other things can kill off a sapling too

Mesquite seem to be hardy I’m finding, but some other species may be more finicky. Plant 100 and you may only be left with 5 after a few yrs. Trees grow through brute attrition. Thousands of seeds, 75% may germinate, half that may only survive the first yr or two, half that may only make it 10yrs. So your propagation techniques need to mimic that to an extent. Trees in your garden will get more love from you than brutal Mother Nature