I've got a small "12x12" in a pot that is in bloom right now. Of course living on the Oregon, azaleas pretty much grow like weeds here.

Sorry, I forgot to address the soil issue. Mine is in Al's 5-1-1 mix and it's awesome stuff once you collect the ingredients.

http://forums2.gardenweb.com/forums/load/contain/msg0214580016564.html?71

Here is a link that might be useful: Al's 5-1-1

5-1-1 should work great, but remember with Azalea's acid soil requirement not to put dolomite lime in. If you do require calcium and magnesium, use gypsum and epsom salts.

You might want to consider the gritty mix as 5-1-1 will break down, just not as quick as commercial soils. If you really want to have soil last, use the gritty mix, with appropriate adjustments for pH.