Tuff Stuff Ah-ha HydrangeaTuff Stuff Ah Ha' is grown for its HUGE double florets that cover the plant for spring and most of the summer! Proven Winners says, "this is one of the most prolific reblooming hydrangeas we've ever seen!" Plants bloom on both old and new wood, meaning you'll get flowers even if we've had an unusally cold winter or late frost. NOTE: Soil pH affects H. serrata flower color. Our acidic soil produces blue to purple flowers, while soil amended with lime