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. Like all hydrangeas, the shrubs are toxic to humans, dogs, cats, and horses.
Light
In their native habitat, oakleaf hydrangeas are understory plants, so they appreciate afternoon shade, especially in southern climates where nearly full shade may be necessary. In the North, oakleaf hydrangeas can get by with full sun. Too much shade may reduce the intensity of the fall color.
Soil
Grow oakleaf hydrangea in well-drained soil with a slightly acidic soil pH (5.0-6.5), amended with plenty of compost.
Water
These plants appreciate moist soil, and the more sunlight they receive, the more water they need. Blanketing the ground beneath the shrub 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.
Fertilizer
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.
Oakleaf Hydrangea Varieties
‘Snow Queen’: 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. ‘Snowflake’: This cultivar is preferred by some growers since it has double flowers. ‘Ruby Slippers’: This cultivar 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 a reddish color, true to its cultivar name.
Pruning
Oakleaf hydrangea shrubs tend to spread out and often do so unevenly with branching in all directions. Annual pruning or trimming back unruly branching every two years will keep your hydrangea shapely and healthy. In ideal conditions, this plant may shoot up to 10 feet, which may require that you trim it down. Since it blooms on old wood, wait to prune until after flowering when blooms start to fade, usually late summer into September or even October. 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. Follow these propagating steps:
How to Grow Oakleaf Hydrangea From Seed
Propagating a popular cultivar such as ‘Snow Queen’ from seed does not produce a plant true to type. Therefor it is recommended to propagate it from stem cuttings as described above.
Overwintering
At the northern end of its hardiness range (zone 5), young plants should be given some winter protection, such as a burlap wrap.
Common Pests & Plant Diseases
Oakleaf hydrangea suffers from no serious pest or disease issues, but non-threatening powdery mildew or leaf blight may occur. Aphids can also sometimes appear.
How to Get Oakleaf Hydrangea to Bloom
Failure to bloom can have several reasons. The shrub might not get sufficient sunlight. While hydrangeas prefer dappled shade, they do need sun to bloom. Lack of water might be another reason. Keep the soil moist and add a generous layer of mulch to prevent the soil from drying out. Avoid fertilizers high in nitrogen, which results in lush foliage but no flowers. Switch to a bloom-boosting fertilizer that is high in phosphorus (P). Be careful when pruning to avoid removing flowerbuds which can also be killed by a late freeze in Spring. If you tried all of those options and your hydrangea still does not bloom, it might be simply too young. Continue to give it the proper care and keep your fingers crossed that you will see it bloom next year.
