Not for this season. It takes time for the chemical reaction in the soil to develop so products to alter the coloring of bigleaf hydrangeas should be applied at least 6 months in advance (ie., late fall) and continue periodically until buds are showing.

And a lot depends on what your current soil pH is and the aluminum concentration in the soil. That can either increase or decease the time frame necessary.

Thanks; I'm following the directions on the soil acidifier package but was wondering if I would get the desired effect this season; next year will be fine; the pinkish blooms are pretty anyway. Thanks for the info