Ken, Here's a pic before I staked it: This is it almost exactly a year ago from pretty close to the same camera angle but much closer up (you can tell how much the foliage has increased by the sheer # of leaves): There are two main leaders at this point, both suffering from the same top-heavy problem and leaning in the same direction. So I used two 6' plastic stakes about 2 feet away and twine+velcro straps to pull them upright and slightly separate them. How long do you think I should expect to leave it staked? I'd rather not do it for long if I can help it . . . just long enough for the branches to strengthen. It didn't have this problem last year but I'd say it has >3 times the foliage now. It's definitely a JM but I can't guarantee how true to bloodgood it will be. It grew up under a mature bloodgood at my dad's house, presumably from seed? Either way I'm expecting it to be large for a JM . . . its parent tree is probably 15' high with an 8-10" trunk, and is at least 15-20 years old. This one is in a spot where that size would be fine, so I'm not worried about its growth potential . . . I just don't want abnormally fast growth to keep it from being the beautiful tree it has the potential to be. Thanks again.

It is very common for some Japanese maples to produce juvenile growth that consists of long, whippy shoots like you describe. Some cultivars are more prone than others. In the ground they tend to outgrow this practice with maturity. Although I grow a lot of JM's in containers, I've not had one do this under these conditions......maybe just not growing one of the more likely candidiates, I guess :-) And of course you can prune a Japanese maple! I know of several professional pruners that specialize in just Japanese maples. And there is always bonsai, which involves nearly continual pruning of these trees to perfect that art. The caution is that unless you know what you are doing, you do risk altering the form or growth habit into something that can be rather horrific. For example - other than bonsai, which is an art in itself - I would never suggest pruning one to maintain a specific smaller size. But you can freely remove any dead wood, conflicting branches, lighten or reduce the canopy or prune to accentuate the growth habit or form. In winter when the tree is dormant and before the saps starts moving is the suggested time for most pruning, or in early summer (June). With regards to the long shoots, if the tree was in the ground, I'd suggest leaving them alone. The rest of the canopy will catch up with them eventually. In a container, these can be headed back if you find them distracting in their appearance. Just prune back to a bud union.

thanks all. Upon further inspection in indoor light (it so happens I had to move plants indoors, then up to roof, while balcony floor is redone), it looks like more branches are brown than I recall in the past....I seem to recall that all branches were usually green...that it was just the trunk that could be brown in parts. Also, in the past my potted maples were kept on top of the ground...during the time I had a dirt yard. It's only been the past three years that I now live in an apartment with no yard...but rather, an elevated (3rd floor) balcony. I learned only recently that elevated balconies create additional concerns because cold winds can affect the pots not only from the top and sides, but from the bottom as well (since the bottom of the pot doesn't have the benefit of the warmer earth underneath it). So....perhaps as long as I continue to live with an elevated balcony, I can't have maples. I also recently searched online, and it seems most maples are only hardy to Zone 5? I saw none that were hardy to Zone 4 or below, and considering I am in Zone 6, I know that my POTTED plants must be hardy to at least Zone 4, and perhaps even Zone 3 due to my plants being on an elevated balcony

I agree. Remove the lower branches that are rubbing off the main trunk. Then try to keep a branch on each side of the trunk.. _ a similar technique is used on making bonsai and so perhaps you should just check out the formal and informal style of bonsai. Not that you should strictly adhere to the method, but it gives you a visual on what branches to keep and what to remain. I try to open up the trunk a bit more to show off its lovely shape and curve. Here's a link as a guide: http://www.bonsaimary.com/basic-bonsai-styles.html