There is nothing quite like finding a large stand of native oakleaf hydrangeas along a rocky-river shoreline or moist ravine in the South. Though you might not have such a picturesque setting, those same monolithic-size panicles of glistening white blossoms can show out in your shady landscape, too.
The oakleaf hydrangea is native from the Gulf Coast as far north as the Tennessee/Kentucky line, but don't let that throw you. It is recommended for zones 5-9, (Lexington is in 6A) meaning that even parts of Michigan and Maine can relish its beauty.
The oakleaf hydrangea has the ability to make a dramatic statement in the garden with its huge deeply-lobed palmate leaves. This coarse texture allows it to fit nicely with ferns, elephant ears and even bananas for a tropical look.
Yet this large shrub screams woodland border, where it can be combined with ferns, hostas, and colorful French or mophead type hydrangeas. In the South they should be combined with Satsuki azaleas for a terrific spring season extender. If you aren't familiar with Satsuki, this means fifth month, which is their season of bloom.
At the Coastal Georgia Botanical Garden we have several. Some are combined with a shorter drift of spreading yew for a terrific contrast in texture. In another area they are understory to a tall bald cypress draped in Spanish moss, which is a portrait of the Deep South.
To grow yours, select a site in partial shade. Keep in mind that these are large shrubs reaching 6 to 8 feet in height with an equal spread. Our oldest ones are approaching 10 feet.
Prepare a bed for your hydrangeas and companion plants by incorporating 3 to 4 inches of organic matter and 2 pounds of a 5-10-5 fertilizer per 100 square feet of planting area, tilling deeply. Dig the planting hole two to three times as wide as the rootball but no deeper. The wide hole allows for the quickest root expansion and acclimation into your garden.
The oakleaf hydrangea blooms on old wood, so if you want to do some pruning, do so immediately after bloom. There is not typically any regimental pruning needed, just a little shaping. Extra-cold winters, however, can cause damage. Let the growth resume in the spring and thus show you the damaged branches to remove.
One other attribute that is often overlooked is the fall burgundy color in the large oak-shaped leaves. This color often will persist late into winter. The Virginia willow or sweetspire also is a nice companion with fragrant white blooms and a similar fall color. The variance in flower and leaf texture makes for a wonderful woodland mix.
There are several choice varieties:. Snow Queen might be the most famous for its upright habit and large blooms that hold up after rain. The U.S. National Arboretum released Ruby Slippers, which is somewhat shorter and more compact. The flowers start off white, age to pink and finish to a deep rose. The fall leaf color is superior. Even more compact is the arboretum's Munchkin, which tops out at 4½ feet with flowers that mature to a medium pink.
Norman Winter is director of the Coastal Georgia Botanical Gardens at the Historic Bamboo Farm, University of Georgia Cooperative Extension, and author of Tough-as-Nails Flowers for the South and Captivating Combinations Color and Style in the Garden.