Linda from Wheelersburg Oh writes
Per the product label: Recheck the pH two weeks after application. If needed, reapply only to those areas where the desirable pH is required to maintain vigorous plants. Hi-Yield Aluminum Sulfate helps create an acid soil condition which is desirable for hydrangeas (blue). By acidifying the soil, Hi-Yield Aluminum Sulfate can maintain or change the color of Hydrangea flowers. Blue Hydrangeas require Aluminum as an acidifier, to retain their blue color. They should not be fed a Phosphate fertilizer due to the fact that it has a tendency to “tie-up” Aluminum.
Answer last updated on: 06/24/2019