Clean your shovel with a solution of one part chlorine bleach to 10 parts water to avoid spreading any disease spores from the shovel back to the soil.
Dig out to the drip line of the dead plant when removing it to ensure that you are removing as much of the root system as possible. Remove any remaining roots or debris from the hole.
Remove the diseased soil to a depth of 12 inches and as far out as the root span of the old plant. Do not reuse this soil to replant.
Sprinkle fungicidal powder into the hole at the rate of 1 cup per square foot.
Add enough clean soil to the hole to bring the crown of the new plant up to the level of the surrounding soil.
Place your new plant in the hole and fill the hole with water. As the water settles, slowly add clean, disease-free soil around the new plant. Continue adding soil and water until the hole is filled.
Poke holes all around the new planting hole with the handle of the shovel to be sure that there are no air pockets.
Sprinkle 1 cup Epsom salts around the top of the hole and water them in.
Gently spread 3 inches of mulch around the new plant.