Hi-Yield Aluminum Sulfate, 4 lb. is specially formulated to create an acid soil condition i for plants like Azaleas, Camellias, Rhododendrons, Gardenias, Holly, blueberries, and others as listed on the label. This product is also effective in maintaining or changing the color of white or pink Hydrangeas to a beautiful blue. It comes in a convenient ready-to-use 4 lb. container and features a 16% sulfur analysis, making it a reliable choice for gardeners looking to enhance their acid-loving plants. Model Number: