Oakleaf hydrangea is a flowering deciduous shrub with white flowers and distinctive leaves shaped like those of an oak tree. It is prized for its long-lasting flowers and its beautiful fall foliage colors. A popular cultivar of this plant, called 'Snow Queen,' can be grown in USDA plant hardiness zones 5 through 9.
Plant Taxonomy and Types
Plant taxonomy classifies oakleaf hydrangea as Hydrangea quercifolia. This is a case where the Latin genus name, Hydrangea, is so widely used that it doubles as a common name. As for the species name, quercifolia means "oakleaf" in Latin.
The cultivar 'Snow Queen' is named for the white flowers produced by the plant during the summertime. It is often confused with 'Snowflake,' which is preferred by some growers since it has double flowers. Another cultivar, 'Ruby Slippers,' may be more suitable for those who garden in small spaces, as they stay more compact at 3 to 4 feet tall and wide. The flowers of Ruby Slippers age to reddish color, true to its cultivar name.
To break down the scientific name, Hydrangea quercifolia, we are all familiar with the Greek root hydr- as a reference to water, as in "hydrate." Meanwhile, angeon comes from the Greek for "vessel." Some people see a resemblance between a hydrangea seed pod and a water vessel. Most species do require a lot of watering (oakleaf hydrangeas often need a bit less water than some other kinds, though).
Traits of 'Snow Queen' Oakleaf Hydrangea
In summer, Snow Queen oakleaf hydrangea flowers in clusters, and the white flowers fade to a pinkish-brown in fall. Their floral display is very long-lasting. But the plant's best-known trait is its oak-leaf-shaped foliage. The leathery leaves are large and turn purple, orangey-bronze, or red in the fall, making the plant a great pick for autumn color.
Snow Queen shrubs typically reach a height of four to six feet and a similar spread, but they can grow to be larger than that. They are multi-stemmed shrubs, and the branches can shoot out from the center in any direction. Peeling bark on the branches offers some winter interest, as well as spring interest. Before the plant fully leafs out in the spring, it offers little visual interest other than the bark.
Sun and Soil Needs
Oakleaf hydrangea shrubs are understory plants in the wild. In southern climates, give them afternoon shade. In the North, oakleaf hydrangeas can get by with less shade. Too much shade may reduce the intensity of their fall-foliage color. Grow them in well-drained soil with a slightly acidic soil pH and plenty of compost. The more sunlight they get, the more you should be watering them.
Pruning and Care
Oakleaf hydrangea shrubs usually require little pruning, unless you are trying to fit them into a location that is too small for them. In such cases, you may want to re-think your plant selection for that spot and simply transplant your Snow Queen to a location where it has more room to grow.
But sometimes, even if you've chosen the right location for the bush, you may be forced into pruning. For example, you should prune if the plant suffers damage (such as from winter die-back). In this case, wait until spring, then cut the affected branches down to just below the damaged areas.
If you do wish to prune to control the plant's size and/or shape, do so right after the blooming period since this type of bush blooms on old wood. Mulch your bushes to keep the roots cool in summer, especially in hot regions.
Best Features of 'Snow Queen' Oakleaf Hydrangea
Technically speaking, the floral display on oakleaf hydrangea comes from sepals rather than flower petals. Sepals are like petals, but they're sterile. Since they can't be pollinated, they can't go to seed. Playing no part in the reproduction process, they give your yard color all summer long. The true flowers on oakleaf hydrangeas are the tiny ones that you see behind the sepals if you look very closely.
With their brilliant fall foliage and long blooming period, oakleaf hydrangea shrubs are attractive enough to function as specimen plants. As understory shrubs in the wild, they are also appropriate in woodland gardens. Their big leaves give them a coarse plant texture, providing contrast with plants with more delicate features. Their flowers can be dried for use in crafts, while the fresh ones make good cut flowers.