Field maple wilting

I have a field maple that has been growing happily for two years in a pot. I got it as a sapling, and it is about 2 feet tall. It came into leaf OK this spring, but over the last month the leaves have turned brown, limp and lifeless.

I tried changing the compost in the pot, to no avail. I was surprised to see that the root network was only about 6 inches long.

Is the maple beyond rescue now? Google suggests the culprit could be verticillium wilt.

 

Its a mystery without pictures of plant and roots.

 

I will try and post some photos. When I changed the compost I didn't notice any grubs.

 

Here's a picture of the frazzled foliage.

I hadn't thought about waterlogging, but it was quite dry here when the problems started, and it's in a clay pot, not plastic. Having said that, the old compost did look quite damp and mossy on top.

 

Doesn't look good, looks pretty dead to me.

 

Yes, it is about ten days since I changed the compost, and it's not showing any signs of life.