4-3-6 Specially blended fertilizer for acid loving plants like blueberries, strawberries, rhododendrons, azaleas, camellias, hydrangeas, evergreen trees, and other plants that need a low pH. Apply early in the spring to encourage vegetative growth and again when blooms appear. 100% natural. Apply 5 pounds per 100 square feet or 1 cup per 2 inches of a shrub's trunk diameter.