Sorry to say, but digging a three foot deep hole was unnecessary and potentially a big problem. When you create a deep excavation, some subsidence is inevitable. You want your azalea to remain slightly above the soil surface, not below it. As the subsidence occurs, you will have a sort of sump which will be much too wet for good growth. When faced with soil containing a good deal of clay, it is almost always better to plant above the surface rather than in the underlying soil. Even if there is good drainage - a distinct rarity with clay - there is not sufficient airspace in clay soils for good growth.

Unless it is being used to increase the water holding capacity of extremely sandy or gravelly soil, the kind of peat moss sold by the millions of bales is pretty much useless as a soil amendment. It is too fine and dust like to provide the airspace azaleas and rhododendrons need and will hold way to much water, especially in clay soil..

So, what to do. Avoid the three foot deep hole.. Near it, make a wide shallow - no more than 6" - depression in undisturbed soil. Use conifer bark, partially decomposed, if available, to create a planting area for the azalea. Keep the rootball slightly above grade and cover it with the bark. The bark is acidic, will decay slowly and provide nutrients, hold water, but also allow lots of oxygen to reach the azalea roots.

Thanks for the help,unfortunately this is the only spot I could put it so I used some peat moss and some Scott's premium top soil and planted it at the soil line.It was only $14.95 so I will keep my fingers crossed it does well in the spot but if not I won't be out much.