Hydrangea, Endless Summer® Bloomstruck® HydrangeaBloomstruck Hydrangea is a compact deciduous shrub able to bloom on both old and new wood. Its serrated dark green leaves with red veins grow on red purple stems and turn red purple in fall. The color of the large panicles of mophead flowers depends on the soil PH acidic soils produce violet blue flowers, while alkaline soils produce deep rose flowers. While not fragrant, the flowers attract butterflies and pollinators. Best bloom in partial sun and