Jacks Classic

This formula contains aluminum sulfate, which lowers the soil pH. Hydrangeas require acidic soil to absorb the aluminum necessary to produce blue pigments in their petals.

It is specifically designed for bigleaf hydrangeas (Hydrangea macrophylla) and mountain hydrangeas, which are the varieties capable of changing color based on soil pH. It will not change the color of white-flowering varieties.

For best results, apply the water-soluble mixture throughout the growing season. Always follow the specific dilution instructions on the label to avoid over-fertilizing your plants.

While it is formulated for hydrangeas, the acidifying properties can benefit other acid-loving plants. However, monitor your soil pH levels to ensure you are not making the environment too acidic for those specific species.

This is a synthetic, water-soluble fertilizer. It is designed for quick nutrient uptake and precise control over soil acidity, which is essential for achieving consistent blue blooms.