Nothing takes the edge off a steamy summer day quicker than the cool white flowers of an oakleaf hydrangea (Hydrangea quercifolia). While not as familiar as billowy blue mopheads or crisp lacecap hydrangeas, these denizens of the southern shade offer four seasons of interest while demanding little more than proper placement, and a splash or two of water during their first year.
Oakleaf hydrangeas have a graceful, mounding habit. A single clump can grow from 6 to 10 feet tall and produce an equally wide spread. In spring, the leaf buds are covered with thick felt-like hairs. They unfold into bright-green deeply lobed oak-like leaves that grow to 8 inches long. When planted in deep shade, they expand to the size of dinner plates. From late spring into mid-summer, oakleafs boast showy 4-12-inch long cone-shaped, snowy white flower clusters. As the flowers age, they slowly turn from white to pink lending an interesting color and texture to the late summer landscape.
In fall, the leaves take on shades of bronze, crimson and purple. The stems have cinnamon-colored bark that peels back to reveal a rich brown inner bark. The combination of colorful bark and papery petals provides a stunning feature in the winter landscape.
Oakleaf hydrangeas are the perfect addition to a woodland garden or naturalized landscape. They look lovely planted singly as accent or specimen plants, make a bold statement when planted in a large group. They can also serve as an interesting and unusual hedge or foundation planting.
Grow oakleafs in full shade or morning sun with afternoon shade?in hot climates they suffer in the afternoon heat. They prefer well-drained, slightly alkaline soil rich in organic matter, such as Miracle-Gro® Moisture Control® Garden Soil, or Miracle-Gro® Organic Choice® Garden Soil. Unlike bigleaf hydrangeas, oakleaf flowers remain white regardless of soil pH.
These tough plants have few serious insect or disease problems and, once established, are remarkably drought-tolerant. Be sure to water during extended dry periods, though, especially during their first year. They require little pruning; just remove an occasional weak or damaged stem. Propagate oakleaf hydrangeas by dividing the clump in winter or, when they have finished flowering, by placing tip cuttings in a shady spot outdoors in pots of moist, sandy soil.
Oakleaf hydrangeas are native to the southeast from Tennessee to the Florida panhandle and west to the Mississippi where they are understory shrubs growing under oaks, hickories, magnolias, and beech in mixed hardwood forests. They are often found living on stream banks and north-facing hillsides. Just the kind of places most of us seek to keep our cool in the summer.