Ericaceous potting compost, assuming you're putting them in pots.

And whether in pots or in the ground remember to feed them.

You do not need to feed in the ground, just in pots! unless you have alkaline soil in which case you'll need to constantly feed!

Mg I have to differ I always give my rhodis in the ground a feed in Spring and Autumn and I have excellent rhodies.

Works well for me.

And mine are all I the ground.

So do we Scotkat and none of them has ever been fed! With over 40 of them in the garden it would take far too long :)

I just have 16 Mg so it's not a problem to do.

Depends on the soil. My mother grew beautiful rhodies in her acid soil. I have to keep mine in pots or feed them regularly with ericaceous feed as my soil is very alkali.

Our soil is, near as damn it, neutral - just very slightly acidic. Our view is we prepare the planting hole for a shrub or tree well and, basically, that's it! We don't clear away any leaf litter around the shrubs so that all rots down nothing else.