A new and distinct cultivar of Hydrangea macrophylla plant named ‘Show Stopper’, characterized by its remontant (reblooming) trait, flowering on old wood and new growth of the season dark pink mophead inflorescences or dark blue inflorescences in non-aluminum or aluminum based media, respectively compact, mounded growth habit lustrous, dark green foliage strong stems that hold the inflorescences upright and moderate resistance to powdery mildew.
