Discovered in 1791 and grown in American gardens ever since, oakleaf hydrangea (
Hydrangea quercifolia) has proven itself to be a beautiful, low-maintenance native shrub (
figure A). Unlike the more familiar and perhaps more temperamental bigleaf hydrangea (
Hydrangea macrophylla), the oakleaf hydrangea is easy to grow and more tolerant of soil conditions.
Oakleaf hydrangea thrives best in a moist, slightly acidic soil. Unlike the bigleaf hydrangea whose flowers can change from pink to blue depending on the soil pH, oakleaf hydrangea flowers are white, regardless of pH (figure B). The blooms appear on the previous season's growth, so don't prune until after the plant has finished flowering. It also needs protection from afternoon sun, especially in the South, but in dense shade it may get a bit of mildew or leaf spot.
Oakleaf hydrangea is hardy in USDA Zones 5 to 9, but its root ball is slightly hardier. The top growth may die back in the winter, but new shoots should appear the following spring. However, don't expect flowers under those circumstances; simply enjoy the beautiful foliage.
Plant size generally ranges from six to 10 feet tall and as wide. Because it sends out suckers, it can be wider than it is tall. Several cultivars offer more compact growth habits; 'Pee Wee' reaches about two to three feet tall.
These shrubs are great for planting at the back of the border, and although they're deciduous, they make a fine three-season living fence.
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