Letting it grow (at least til next early spring) would be a good idea, give you time to learn more (there's a ton of stuff online about them) and let you watch how it grows. Next spring would be the time to prune whatever you choose to - now is definitely not it.

Japanese Maple Bloodgood -

I just bought one about a month ago because of its nice red leaves it provides good tree!

Well this is what I know, as a Bonsai this tree is one of the most easiest trees to grow and develop into an amazing bonsai.

it is a lover of acidic soil so that is an option to consider taking care of.

Also it does not need a lot of light, it needs to receive on average 6 hours of light preferably in a well shaded area.
The tree at this time should bloom in red foliage, but will not if it receives to much light.

IF the tree gets shade it turns red if it gets to much light leaves go green, truly an amazing tree...

as far as the development of its trunk, and size pruning is always a good technique to keep the tree at a good size however I would let it grow so that it can develop a strong and sturdy root system.

once it is grown I would transplant into a smaller Bonsai pot for its new beginning, its done well I can see the red over lapping some leaves -

from here on out its patience, I would say about 2-3 years of growth until its ready, but remember the size is up to you, for example mine stands about 3 1/2 feet tall- this fall I will be designing it!!

GOOD LUCK AND EXECELNT CHOICE !! STAY SHADED!!

I think the best starting point is to find your local club.

Can't tell if the photo was taken the same day as potting or if has had time to get over the shock. I see big leaves on top growth and longs spaces between nodes (and no browning leaves).

Best time to repot would have been spring, just as buds open. But I'd leave it for now unless you think a *lot* of roots were damaged -- in which case I would clip the long branches now. Come spring, you'll replace the heavy 'ground-soil' with gritty bonsai soil and remove 1/3 to 2/3 of top growth and roots at the same time, to keep it in balance and encourage side branches. You'll want to decide on a style -- Look through lots of books for inspiration and ask your tree what it thinks about that.

Not sure why, but I never tried a Japnese maple until two years ago, given seedlings a fellow at work pulled from his lawn -- weeds to him. One died immediately, two more over the winter. (Pots too shallow (?) I think they like deeper ones.) And the two that remain are not quite ready to start shaping. Growing in the ground is the fastest way I know to fatten up the trunk and I should have done that -- again, I don't know why I didn't.

I am told the leaves will reduce greatly but there is a trick to it -- I need to consult my own club gurus...

Have fun with it.

Thanks everybody for your input, it is greatly appreciated! This tree was pulled out from a crack concrete steps, and I am assuming some of the roots were damaged or torn, so I will keep it in this larger pot for the rest of the season and into spring. I will then plan on cutting back some of the taller branches, however I think it might need another year in this pot to establish a new & stronger root system. Lets hope it survives, I would love to have a fully established jap maple bonsai someday from a random seedling growing out of concrete!
Thanks!

Well I did the same thing just a few weeks ago with my kashima, even though now is not the best time. It's my first serious bonsai attempt too. I posted some pics of mine in this forum -- search kashima. It's in a training pot now.

Obviously, I'm not an expert but my two cents is make sure thats really well drained container mix, let it grow. Can't make a cool bonsai until you have a nice trunk.

Hi, I'd like to correct a couple of things - maple roots grow sideways, so deep pots are not necessary, but wide ones are... and 6 hrs of shaded light are not at all enough for them - add at least 5 hrs to that and a lot of those in sun except maybe for midday in very hot areas! Do keep them in partial shade for a few wks after rootwork in spring, but otherwise, no problem.

This post was edited by moochinka on Thu, Jul 24, 14 at 21:39