HORTICULTURE

Detailed explanation-1: -To obtain a blue hydrangea, aluminum must be present in the soil. To ensure that aluminum is present, aluminum sulfate may be added to the soil around the hydrangeas. Authorities recommend that a solution of 1/2 oz (1 Tbsp) aluminum sulfate per gallon of water be applied to plants throughout the growing season.

Detailed explanation-2: -Because aluminum is toxic to plants, bigleaf hydrangeas sequester the aluminum in its flowers, turning the petals blue. The pH of the soil affects the availability of aluminum uptake, which is why acidic soils promote blue hydrangeas since there is more aluminum available to absorb.

Detailed explanation-3: -We can temporarily overcome soil pH limitations to influence hydrangea flower color; as every gardener knows, adding lime raises soil pH and might induce pink flowers, while ammonium sulfate can acidify the soil and enhance hydrangea bluing.