Recently I visited a home where azalea plants, which had only been planted less than 6 months ago, were dead or dying.  Normally we would suspect insufficient watering, but this was not the case.  I dug up several plants and discovered several problems among which were that the root balls were still intact, showing little if any signs of new root growth, which indicated that they were still pot bound.  This is a common problem, due in part to the way nurseries grow azaleas.  To correct this problem, all that you must do before placing in the ground is, with a sharp knife, make a vertical slice approx. ½” deep every 3-4” around the outside of the root ball and across the bottom of the ball.  With your hands, slightly open these cuts before planting.  A second problem I discovered was that the plants had been planted too deep.  Because of the compacted root ball, new roots had been trying to develop above the top of the ball, but unfortunately not enough for these plants to survive.  Also remember, azaleas like water.  Make sure they receive sufficient water, otherwise they will become stressed and most likely die.