Oakleaf hydrangea (Hydrangea quercifolia) is a flpwering deciduous shrub with large clusters of flowers and large distinctive leaves with lobes like those of an oak tree. (Quercifolia means "oakleaf" in Latin). This shrub is prized for its long-lasting flowers that emerge white but gradually transition to purplish pink. Typically growing 4 to 8 feet tall, this multi-stemmed shrub spreads by suckering, and has a rounded upright growth habit.
Oakleaf hydrangea makes a good specimen plant, and it also works well as a foundation plant or when massed in shrub borders or open woodland gardens. The big leaves give these plants a coarse texture, providing contrast with plants with more delicate features. Fall foliage color is attractive—the leathery leaves turn purple, orange-bronze, or red. The peeling, exfoliating branches also provide winter color and texture.
The flowers can be dried for use in crafts, while the fresh ones make good cut flowers.
|Botanical Name||Hydrangea quercifolia|
|Common Name||Oakleaf hydrangea|
|Plant Type||Deciduous flowering shrub|
|Mature Size||4 to 8 feet tall, similar spread|
|Sun Exposure||Full sun to part shade|
|Soil Type||Rich, well-drained soil|
|Soil pH||5.0 to 6.5 (acidic)|
|Bloom Time||May to July|
|Flower Color||White transitioning to purplish-pink|
|Hardiness Zones||5 to 9 (USDA)|
|Native Area||Southeastern U.S.|
How to Grow Oakleaf Hydrangea
This shrub will do best when planted in a slightly acidic, rich, well-draining soil in full sun or part shade. It thrives in moist soil; a thick layer of mulch over the root zone will help retain soil moisture.
At the northern end of its hardiness range (zone 5), young plants should be given some winter protection, such as a burlap wrap. Oakleaf hydrangea suffers from no serious pest or disease issues, but non-threatening powdery mildew or leaf blight may occur. Aphids and spider can also sometimes appear.
In their native habitat, oakleaf hydrangeas are understory plants, thus they appreciate some afternoon shade, especially in southern climates, where nearly full shade may be needed. In the North, oakleaf hydrangeas can get by with full sun. Too much shade may reduce the intensity of the fall color.
Grow oakleaf hydrangea in well-drained soil with a slightly acidic soil pH, amended with plenty of compost.
These plants appreciate moist soil, and the more sunlight they receive, the more water they need. Blanketing the ground with a thick layer of mulch will help maintain soil moisture.
Temperature and Humidity
Oakleaf hydrangea generally does well in climate conditions throughout its hardiness range (zones 5 to 9), but winter damage to flower buds may occur in the colder part of the range, especially with young shrubs.
This plant generally requires no feeding, especially if you are mulching over the root zone. When growing in alkaline soils, occasional feeding with an acid fertilizer may be beneficial.
Pruning Oakleaf Hydrangea
Oakleaf hydrangea shrubs usually require little pruning, unless you are trying to fit them into a location that is too small. In ideal conditions, this plant may shoot up to 10 feet, which may require that you trim it down. This is a shrub that blooms on old wood, so when pruning is necessary, do it immediately after it is done flowering. Damaged or diseased branches can be cut away whenever they appear.
This plant spreads through suckering, so you may want to remove spreading ground shoots to control the spread of the shrub.
Propagating Oakleaf Hydrangea
Oakleaf hydrangea shrubs can be successfully propagated through stem cuttings. Snip two to four cuttings from green stem tips that have no flowers. Make sure the cuttings have at least one growth node (a knobby line across the stem).
Trim the top half off the leaves, dip the end of the cutting into rooting hormone, and plant the cuttings in moist, sterile potting mix. Place the planted cuttings in a plastic bag and keep it out of direct sunlight. Make sure the soil remains moist but not soggy. Within about 12 weeks, root growth should be sufficient to transplant the plant into the garden or into a larger pot for continued growth.
Varieties of Oakleaf Hydrangea
One of the most popular cultivars of oakleaf hydrangea is 'Snow Queen', which produces panicles of white flowers in early summer that gradually fade to pinkish-brown by fall. The floral display is very long-lasting.
Another cultivar is '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 it stays more compact at 3 to 4 feet tall and wide. The flowers of 'Ruby Slippers' age to reddish color, true to its cultivar name.