How much aluminun sulphate should you apply to blue spruce?

To enhance the blue color of blue spruce (Picea pungens), you can apply aluminum sulfate at a rate of about 1 to 2 pounds per 100 square feet of soil around the tree, ideally in the spring or fall. It's important to evenly distribute the aluminum sulfate and water it in well to help it penetrate the soil. Before applying, it's advisable to test the soil pH to ensure it is suitable for the tree's needs, as blue spruce prefers slightly acidic conditions. Always follow the manufacturer's instructions for specific product recommendations.