With such a broad range of hydrangeas on the market, it's handy to have this display of species and cultivars side by side. Desired for their summer blooms and large white to pink/purple flower heads, hydrangeas range in size from 2' to 8' depending on the cultivar. Hydrangea paniculata cultivars are generally upright and flower best in full sun, while the mounded cultivars of the Japanese, H. macrophylla and H. serrata, do better in some shade. "Hydra" is Greek for "water or water serpent," so sun or shade, hydrangeas need moist soil. Those most drought-tolerant are our native H. arborescens. Their coarse leaf texture (from big leaves) is a useful design contrast to fine textured shrubs.