ALT Oak Leaf hydrangea in sophisticated fall colors of pink, burgundy and purple, with dried flowers, photography. Seen while walking the grounds of Winterthur Museum. The Hydrangea quercifolia was declared the official state wildflower of Alabama in 1999. Fall is when the oakleaf hydrangea really makes an impact with its rich, deep burgundy/purple foliage that persists into winter. The dried tan or light brown flower heads add additional interest. In winter, the exfoliating tan bark provides an additional textural element to the snowy landscape.