Oakleaf Hydrangea (Hydrangea quercifolia) is a fast-growing, deciduous shrub native to the southeastern U.S. known for its large, cone-shaped white flower panicles in summer and deeply lobed leaves that turn brilliant red-purple in autumn. It thrives in USDA zones 5-9, growing 6-10 feet tall with exfoliating cinnamon-colored bark, providing year-round interest and partial shade, well-drained soil, and consistent moisture.