Transporting an acer tree

I can wait until the autumn, but what is the significance of it being root bound or the soil falling away in relation to best time to re-plant it?

 

Well, you don’t really want to disturb the rootball too much in the growing season hoofy.
If it happened in the dormant season it wouldn’t really matter too much ...although autumn isn’t exactly dormant time it is a good time to move plants ​

 

I've just noticed that a few leaves at the end of one of the branches have gone brown and shrivelled. Is this a sign there's something wrong or would the problem be more uniform around the tree rather than in just one place if something was wrong?

I suspect slight damage when I was transporting the tree but I thought I'd ask here just to be sure.

 

It will have been affected somewhat by the transport, the new site and new conditions hoofy. Not the ideal time of year to change things for it plus, if your summer is anything like mine, the sun will have been pretty strong.
Have you kept it watered?
I would accept it looking a tad below par for this year but expect it to have settled by the time new foliage forms next spring
Relax I think hoofy

 

Thanks for the reassurance Verdun. I have kept it watered so that shouldn't be an issue.

My concern really is that right now it is in the half barrel container in pretty much full sun and that's where I intend to plant it come the autumn, but if it won't tolerate the spot now is the time to decide before it's in the ground.

 

It won’t like full summer sun though hoofy
I have a very sunny garden here and grow only one Japanese acer. This is protected from mid day and afternoon sun partly by tall plants. Miscanthus Variegatus for example grows 8’ tall and helps cover my acer. Maybe you could do the same or find a protected corner somewhere!

 

I planted a small one around 5 years ago. It’s huge now. Going to be a very big tree.

It seems to love the sun.