Sadly it isnt unusual for hardy plants to die and maple death is quite common. When you say it did not have a large root ball what were the roots like-other than being brown. Did you try lightly pulling on a few to see if they were alive or dead? I trust this was a pot grown plant and not a "potted plant" by that I mean field grown and then lifted and potted this winter/spring which can often give you a plant with a small root system.
Dont be tempted to keep watering the tree. If it is damp that is good enough as you can easily overwater plants we have many customers who over water their plants causing root rot-the plant wilts due to the loss of root so they give it more because it looks dry which increases the problem.

Thanks for the reminder about overwatering. It's very tempting, when a plant starts drooping, just to assume that it needs more water. Yes, it was a pot-grown plant. Unfortunately I didn't see what the rootball looked like originally, because I didn't do the potting on myself. However, when I knocked the plant out of its new pot, the rootball was very small and there seemed to be lots of small white roots breaking off into the compost. The leaves are all completely wilted and browning. I wonder if there's any chance it will survive, if I reduce watering and leave it to recover? Should I prune back the affected leaves (i.e. all of them)?

My Japanese Maple in a huge pot (planted in early May by a nursery, so I am assuming it was pot grown)is having the same problem -- leaves browning and falling off. I had skipped 2 days of watering (had been advised to water every day until the water came out of the bottom of the pot). That is when I noticed the browning of the leaves. I then began watering every day, but the problem continues. This tree cost a small fortune -- and the nursery couldn't guarantee it's survival since it was to be planted in a pot. Any thoughts would be ENORMOUSLY appreciated.

Many thanks,

Marion

I too have a problem with my acer leaves turning brown!I bought mine a couple of years ago and it has looked beautiful till now. Mine is in the ground and is about 4 foot tall, it does not look at all happy! could this be because of the hot sun? would it stand a chance if I tried to move it at this stage

Marion: I can't imagine why the nursery advised you to water your maple every day. Roots need air as well as water, and the roots of a Japanese maple will start to die if they are sitting in soggy compost. Also, overpotting (moving a plant into a pot that's more than a size or two larger than the one it was in) can result in the roots being in contact with a mass of stagnant compost, which in turn can result in plant death (I have killed off a couple of acers myself, over a period of two years or so, by overpotting). I would hold off on the watering. In cases where the plant is of manageable size, it would be a good idea to tip it out of its pot to examine the roots (if they are brown and mushy, or breaking off, then they are dead), and maybe repot into a smaller container. However, by your comment about its cost, I'm assuming it's pretty big and this course of action isn't an option!

Sandie: Japanese maples have quite delicate leaves that can get burned in hot sun (some varieties will suffer badly, others much less so). Could you perhaps provide some temporary shade to keep the worst of the sun off it? Also, if the area where it is planted is dry, it may benefit from supplementary watering.

Hope this helps.

I had an Acer Palmatum which I planted in the garden, it thrived for 4 years then last year the leaves were scorched after a bout of rain then strong sun. This year it is doing nothing it usually has loads of buds on by now. Could the very wet winter have killed it off or should I give it a bit longer before I dig it up? Any advice would be appreciated

Acers that are red in leaf can take more direct sun longer, if green leaves, variegated, aka green, pink, white, etc, not so much, usually early morning sun but they need protection from noon and especially afternoon, hottest part of day sun. It makes where to plant them a pain. My red maple does fine potted in full sun, have a green acrer that is potted but the garage blocks the 3 pm western sun. My butterfly Acer which is delicate and variegated was planted at the front of my 3 story house northeast side, it can get some eastern sun rise but by 11 ish the house shadows it as does a neighbor's tall 2.5 story house. Does well there in clay soil, clay soil not being ideal, it is a good 15 foot tall. My theory is they dehydrate. And no, you should never water them in hot bright sun light in a way that get their leaves wet. Not sure why, they seem to hate it. Maybe when it rains in nature it is cloudy, no sun, LOL. I just know they are picky.