At this point I wouldn't move them out unless your weather has already started to warm up. They look pretty happy where they've overwintered, so I would carefully report them into new pots. But I wouldn't start any bonsai process yet. They're still lil guys. Repot them in their own containers and if they were mine I would let them really grow out this year, and maybe even next year. HTH

Thanks, Kev. I am hoping to grow them as a single grove of 3 trees. Should I still separate them into their own pots and then combine them into a bonsai planter to form the grove after a couple years? Also, would you recommend giving them each a 4" pot or something slightly larger that they can grow in to?

If they were mine I would separate them. They may be nicely grouped now, but as they grow they will quickly crowd each other out. Plus unless you already know it will be a small bonsai, you should let them get to their potential. A number of years ago I sat in on John Naka's demo as he put together his forest planting "Goshin 2". Those trees were from 15" to 30" tall. You may not want something that big, but as they grow you may see something else in them that draws your eye.

For training pots I like bulb pots or trays. They come in the same sizes as regular pots but are squatter (is that a word?) -

I usually get 10" or larger for my "in training" shohin size trees. It gives the root lots of room to run without letting them get too deep. This way, IMHO - the amount of roots taken off when the time comes is lessened. You could probably find them in the garden section of the big box stores (I just order mine online). But hey, if you have regular pots sitting around- Use 'em, why waste the $. ;) HTH

Kev: Do you have a favourite vendor for these pots? I had been looking for some wider ones. Like 18" for a rather large ficus I have.

Jesse, as Kev suggested you will be better off with letting them grow freely in individual pots in a well draining mix. Look for gritty-mix or 511 mix in container forum. It will be overwhelming at first but you will soon want to try them. Keep them outside next winter in a sheltered spot. I think you will be fine this time without having given it the required dormancy period. The key is to give them the space to grow initially. Although bonsai just means 'plant in a pot', what it practically means is 'patience'. Let nature do its work first before you start making plans for its destination.

I use this place MA Bromeliads out of Fl. They maintain an ebay store - http://stores.ebay.com/MABromeliads.  I just picked up a doz. 12" bulb pots. Safely packed and got quick delivery.

ToC, you're right. There's no hard and fast rule. When I answer Q's I always use IMO - because if you ask 10 people you could get 10 answers and they will all be correct if it worked for them. I just take it from my experience when I used to buy trees for a forest - I had a nice 12 tree Trident maple forest - that they all came in their own pots and you had to pick and choose which ones went where. There is a sort of *formula* but that's for a little later on.

Thanks for the link. Interesting store. But I could not find the 12" pots or anything larger. I guess the larger ones will be harder to come by.

Oops, my mistake I didn't get the 12" I got the 10" -

http://tinyurl.com/zpkzwn5

Thanks for the advice, everyone. I think I would like to keep them on the small size but will transplant them into individual containers for a couple years and see if there are any surprises that would make me change my mind on the small grove arrangement.

Hi again everyone,

I let the little maples grow in a 6" pot outdoors since I last posted in Spring of 16. One has gained quite a bit of height but is definitely dominating the other. I am attaching a current photo.

Should I be doing anything to them at the moment? Pinching out or defoliating? Or should I repot them to a larger pot and let them keep going for another year? I think I am going to go for shohin size with these.

Also does anyone have a recommendation for a good bonsai book? I have The Complete Practical Encyclopedia of Bonsai, but being an encyclopedia it doesn't have any section that gives a more step by step of what to do when in order to get from tiny sapling to bonsai.

Thanks in advance!

-Jesse

IMHO and FWIW I would separate them and put each in a larger pot. But being its late to transplant, I would be very careful with the roots and after transplanting keep it semi-shaded and keep an eye on the watering.

Even if you want shohin, you'd still like the trunk near the nebari to be thick (the thickness is what mimics age). Once in these pot I would just care for them but leave them for a few years to thicken up. I wouldn't touch any growth near the bottom. This will also aid in thickening the seedling up Also feed with fert where the first of the 3 numbers is larger. This will help with leaf growth. HTH

If you can grow them in ground - they will grow much faster. You need to get the trunk to thicken and become woody. Getting them into a bonsai pot now is not very useful. And while it is growing for the next few years you can start reading and practising.

Your first goal is to keep them alive and healthy. And so you need to learn about soil, watering and fertilizing. Head over to container forum and read these two first:

http://forums2.gardenweb.com/discussions/1389927/trees-in-containers-iii

http://forums2.gardenweb.com/discussions/1403195/container-soils-water-movement-and-retention-xvii?n=160

The above two will get you started on a new journey.

There are a ton of good websites on bonsai. bonsaiempire has an introductory video and other online lessons. bonsaiboon also has online courses. I have not really taken the courses myself but they seem like good starting places to get an idea of the art and science of bonsai.

Thank you both for the advice!

I've had pretty good results sticking seedlings in a good-sized cardboard box full of fairly fluffy potting soil, if you're not looking to spend money on a big growing box. When you reply them properly (during dormant season) you might want to cut off the tap root to encourage lateral root growth.

I have also gotten good results from taking whips and planting them in shallow collandars to develop nebari. They will start off with a shallow root system rather than developing their tap roots, and it should improve when I move them into grow boxes to thicken up in a couple of years.

Tap roots?? Japanese maples do not produce any tap roots. In fact, very few tree species do.

As adults? No, because you can't tell them from the rest of the anchor roots.

As seedlings and saplings? Yes. Yes they do. I've had eyes on dozens of them.