Buy Endless Summer BloomStruck® Hydrangea online. Introducing the newest addition to the Endless Summer® collection of reblooming hydrangea, BloomStruck™ provides endless blooms and continues to live up to the Endless Summer promise.Blooms repeatedly on old and new growth producing flower heads measuring 3"? 5'' across. Flower blooms range in color from rose-pink to violet or blue flower heads are held upright on striking red?purple stems. As with other hydrangea, soil PH determines BloomStruck's flower color.Red petioles and red veins combined with glossy dark green leaves adds to this plant's allure, making it stand out in the garden well before flowers even open. Bred by Dr. Michael Dirr, Plant Introductions, Inc. in GA, BloomStruck has extremely strong stems, above average heat tolerance and great disease resistance, especially to powdery mildew.