Dr. Earth Acid Lovers Rhododendron Azalea Camellia Fertilizer can be applied before planting. You will add 2 cups per 1/2 cubic foot (~ 5 gallons) of soil that will be added to the planting hole. Once planting is completed, add an additional 1 cup around the plant and mix into the soil then water thoroughly. 
 
The nutrients are released quickly so the results will be quick but will also continue to feed for several months to come.