Acer Problems

sorry I keep going on..... sounds like the clay has dried out as well

4 years its got a better chance of coming back to life Woo

 

Soak it well-and-truly Woo, and repeat once or twice a week until Autumn. Even on clay ... my clay is definitely still plenty damp enough, tot he feel and the eye, once you get down 6" or more, but I have plenty of plants with deep enough roots that are not looking happy, but are perking up with irrigation. Fingers crossed for your Acer too. Even if it loses all its leaves I, too, would leave it until next Spring to see if it makes a come-back (although mediocre come-backs tend to be followed by up-curled-toes the following year )