Oakleaf hydrangeas have massive flower heads and boldly sculpted leaves. Flower color includes pink, white, green and burgundy, with some varieties changing colors as the blooms age. In fall, the foliage also changes to some of the most favored autumn shades. Oakleaf hydrangeas can grow up to 10 feet tall, depending on variety. If your hydrangea needs a trim, do so after it's done flowering at the end of summer. These bloom on old wood and need time for buds to set for the following spring. Make these vigorous beauties a focal point in your landscape. Plant in full sun to part shade and watch the display.