The oakleaf hydrangea is a deciduous tree that thrives in sun or partial shade. It generally requires well-drained soil, and can grow to a height of up to 8 feet. Its thick, green, leathery leaves are large and help to keep the tree cool in warm weather. The oakleaf hydrangea is part of the Hydrangeaceae family, and thrives throughout much of the United States. Its delicate, small, white flowers have made it a popular tree in public parks as well as private gardens. This tree, which has a shrub-like appearance, is one of the largest members of the Hydrangeaceae family. It blooms throughout the spring, summer, and even into autumn.