12 hours of sun a day is probably too much for any JM anywhere and even more so in a hot summer climate like NC :-) And this tree will get far too large for that location...eventually the tree could reach 20'x20' - 'Osakazuki' is a rather large growing selection of JM!! I would site it at a minimum of 10' away from any fence or other structure. I'd seriously consider relocating where it has more room and at least partial (afternoon) shade :-))

Thanks Gardengal! I planted it so close to the fence because my yard is small, and I plan on limbing it up so it grows over the fence. From what I have seen the Osakazuki grows pretty upright, so it may be good.

I was afraid about the sunlight. I do have a river birch that is still small but would eventually provide late afternoon shade. Should I provide shade with a stake and sheet so that the JM can establish, and then maybe it would have shade from the river birch by that time? I know the osakazuki is one of the most tolerant JM for sun, heat, and humidity.

Unfortunately I don't really have any other spot for this tree!

Yes that is too much sun for a little tree. Yes I would try and shade it for some time to help it recover.