I planted a new azalea and it died. What did I do wrong?

It may have simply dried out. If you plant azaleas in late spring, it is very important to give them some extra water while they are growing new roots. Never let the soil completely dry out it’s best to keep the soil evenly moist. Too much water or poorly drained soil might be another explanation of sudden azalea death. Azaleas have very fine, fibrous roots that are easily damaged by waterlogging, even for short periods of time. Before you plant your azalea, dig a hole and fill it with water. If the water has not drained out of the hole within one hour, the soil is poorly drained and you must correct the drainage problem before planting. Install a perforated pipe or drain tile in the garden, making sure that the outlet is lower than the bottom of the planting hole, or build raised beds.