I don't think lining your planting hole with ericaceous soil is a brilliant idea - you'd be better off digging it in to the planting area generally, otherwise, as the roots of your Acer begin to hit something altogether different than the compost (your soil) trouble will occur. Japanese Acers don't like limey soils rather than needing an acidic soil - yours may be chalky, not limey. Dig in the ericaceous compost to the area generally together with plenty of well rotted compost, feed liberally in spring and every 6 weeks with a general/compound fertiliser such as Growmore up to end of June and see how it goes.

An alternative to planting in your slightly alkaline soil would be to carry out some judicious root pruning - as you would to bonsai the tree - and replant in a big pot. Along with some top pruning you could completely rejuvenate your acer.

Thank you to the two advices As I have already dig the hole I do want to put it in the garden.So I ,ll carry on with the first advice. I will still have to do some pruning to make it look a bit better How about I mix the ericaceous with the dig out soil to back fill would this be less of a shock.I say this because the container it sits in at the moment was filled with a mix of multi purpose and ericaceous composts and just grew and and grew.

I sort of hope you're digging a hole much bigger than you actually need - adding well rotted compost will be good as well as ericaceous, so what I'm saying is to dig it all in in, say, an area twice the size you need, then dig your hole and plant the Acer.

And a lot deeper as well! I feel for you with clay as I had the idea that I would demolish the raised beds in my yard until I discovered completely undisturbed clay at ground level - I cleared as much of the rank, sterile soil out of the beds as I could in the areas where I was planting but nothing has more than 16" depth in which to grow before it will get to the clay - the camellia I planted will be cosseted with extra ericaceous feed, tea bags and coffee - if it survives the winter.

I was puzzled by the "plastic bag the plant sits in". Not sure what you meant. If it is still in a plastic bag you need to remove it before planting it again.

I expect, Steragram, that the plastic is merely a liner between the wooden container and the compost, probably in an attempt to protect the wood on the inside a bit.