Oakleaf Hydrangea: Planting, Care & Pruning

The oak-leaved hydrangea, or oak hydrangea, inspires with its eponymous oak-shaped leaves and white flowers. We will show you what you should consider when planting and caring for this type of hydrangea.

The oak-leaved hydrangea is a real eye-catcher in the garden with its lush panicles of flowers and the characteristic oak-leaf-shaped leaves. The decorative leaves, which are reminiscent of the shape of the American red oak, take on a pretty coloration in autumn.

Oak-leaved hydrangea: origin, characteristics and flowering period

The Oakleaf Hydrangea (Hydrangea quercifolia), also called oak hydrangea, is a species of the hydrangea family (Hydrangeaceae). It originally comes from the southeastern United States, where it thrives in dry forests and steppes.

The oak-leaved hydrangea grows as an upright shrub about 1 to 2 m high. It also grows to a width of about 1 to 2 m, sometimes even wider with age due to the formation of runners. Its flowers open between July and September and are arranged in conical to rounded panicles of about 15 cm in size. They are composed of sterile pseudoflowers and fertile flowers. The pseudo flowers usually have 4 to 5 petals and are 3 to 4 cm in size. At the beginning of flowering they are pure white, later they turn reddish. The fertile flowers are densely packed between the pseudoflowers and are less conspicuous. While the sterile flowers serve to attract insects, it is the fertile flowers that provide pollinators with pollen and nectar.

The special feature of the oak-leaved hydrangea, which also gives it its name, is the striking shape of its leaves. The 10 to 20 cm long, about 15 cm wide leaves are pinnately lobed and are very reminiscent of the foliage of the American red oak (Quercus rubra), especially since they also turn red, dark red or even violet in autumn. In summer, the semi-evergreen foliage is deep green on top and grey-green on the underside. The upper side is wrinkled, the underside is felty hairy. The shoots also initially have a reddish felt, but this decreases with age.

Oak-leaved hydrangea: the most beautiful varieties

The varieties of the oak-leaved hydrangea differ in the structure of the flowers, in the autumn colors and in the growth height. The following varieties are extremely ornamental and will particularly enrich your garden:

the sort Hydrangea quercifolia 'Alice' grows to a height of 1.5 to 1.8 m and a spread of 0.5 to 1 m. It produces large numbers of luxuriant white and later soft pink colored panicles of flowers. The foliage initially appears in a strong green and contrasts wonderfully with the bright white flowers. Later the leaves take on a pretty fall color.

The 'Snowflake' variety forms filled pseudo-flowers and is therefore a real eye-catcher. It grows 0.8 to 1.5 m high and 0.6 to 1.2 m wide. The large, oak-leaf-shaped leaves turn reddish to bronze in autumn.

The 'Ruby Slippers®' variety grows somewhat more compactly. It reaches a growth height of 1 to 1.5 m. In the course of flowering, their flower spikes first take on a pink and later a dark red colour.

Planting oak hydrangea: location and timing

Oakleaf hydrangeas can be planted all year round. The prerequisite, however, is that no frosts are to be expected on the days around the planting.
The hydrangeas prefer a sunny to semi-shady and sheltered location in the garden or on the balcony. The soil should be fresh to moist and humus rich. On sites that are too nutrient-rich, the shoots only mature to a limited extent before the frost, so that they can be more frequently affected by frost damage. Large amounts of fresh compost before planting are therefore not appropriate for the oak leaf hydrangea.

The oak-leaved hydrangea is sensitive to waterlogging, which is why a drainage layer, for example made of gravel, should be introduced in the case of compacted or very heavy soil. Such a layer is also absolutely necessary for potted plants.
Compared to other Hydrangea Species, which are very sensitive to a high lime content in the soil, the oak-leaved hydrangea is lime-tolerant. The soil pH value can also be slightly higher for oak hydrangeas than, for example, for garden hydrangeas. It should be in the neutral to slightly acidic range. Nevertheless, the oak-leaved hydrangea also avoids lime and should therefore never be limed.

When you have found the right place, you can plant the oak-leaved hydrangea. Dig a sufficiently large planting hole in the flower bed. It should be about twice the size of the root ball. If the soil in your garden does not meet the above requirements, you can cover it mix one third with sand to increase the substrate permeability and mature compost mix in Alternatively, you can also buy peat-free potting soil and mix it with sand in the above ratio to get the optimal substrate. For example, our is suitable for this Plantura organic universal soil ideal – it contains all the important nutrients in a balanced ratio. The pH value of 6.1 to 6.9 is in the slightly acidic to neutral range and is therefore suitable for the oak-leaved hydrangea.
Put a small part of the substrate back into the planting hole and place the plant ball in the middle. By loosening the root ball with your hands or a spade, you will inflict small injuries on the roots, which will encourage root growth and branching. The planting hole is then completely filled with substrate, the soil is pressed down and generously watered. If you want to plant several hydrangeas next to each other, you should keep a planting distance of about 2 meters.

Tip: Freshly planted hydrangeas benefit greatly from a watering rim, which you can simply model from excess soil after planting. This is regularly filled with water and prevents the irrigation water from running away unused.

The oak-leaved hydrangea is also suitable as a potted plant for the balcony or terrace. Choose a sufficiently large planter with a drainage hole so that excess water can drain off when watering and no waterlogging can occur. In order to avoid the formation of waterlogging, potsherds should be placed on the bottom of the vessel.

Care of the oak-leaved hydrangea

As with all hydrangea species, a good water supply is the basic requirement for the successful development of hydrangea plants. Young plants in particular need to be watered daily. Apart from occasional fertilization and pruning, however, no special care measures are necessary.

Water and fertilize oak hydrangea

Newly planted hydrangeas need to be watered daily so they can grow well. In dry, hot periods of summer, you should also water oak-leaved hydrangeas once a day, and in pots maybe even twice a day. Even if oak hydrangeas are more lime tolerant than others Hydrangea-types, you should preferably use low-lime rainwater. Oakleaf hydrangeas love cool, moist soil. This is most easily achieved with a mulch layer of leaves or bark mulch. Such an overlay serves as protection against evaporation and keeps the moisture in the soil longer.

Tip: Water your hydrangeas in the mornings and/or evenings when the sun isn't really shining so that the water is used efficiently and doesn't evaporate immediately.

Potted hydrangeas in particular should be fertilized annually, preferably in spring, so that they can start the growing season well. Our is suitable for this Plantura organic hydrangea fertilizer optimal. With its long-term effect, it reliably supplies your hydrangeas with all the necessary nutrients and prevents typical deficiency symptoms and diseases. Work the fertilizer in flat and, if necessary, also cover it with a layer of mulch made of leaves or similar so that it starts to work quickly.

Tip: Fertilizing too late makes plants susceptible to frost, as this inhibits the ripening or hardening of the shoots at the end of the growing season. It is therefore recommended to fertilize for the last time in May/June. Further information can be found in our special article on Fertilizing hydrangeas.

Pruning oakleaf hydrangea

Oak-leaved hydrangeas have a beautiful, upright growth habit. They can be pruned if necessary, but the plants will develop splendidly even without pruning. Only the shoots and panicles that have frozen or dried up over the winter should be removed in the spring. Using clean pruning shears, cut the dried flowers off just above the new flower buds.

Oak-leaved hydrangeas overwinter

Oak-leaved hydrangeas are hardy here. When buying, it is best to make sure that you select well-hardened plants from specialist shops. Plants from nurseries are often preferable to plants from garden centers. Well-hardened hydrangeas are hardy down to -23 °C, provided they are not exposed to the cold and damp winter wind. Even young shoots survive temperatures down to -10 °C without damage. If you still want to be on the safe side, you can cover the ground around the base of the hydrangea plant with leaves or fir branches. In this way, their roots are not damaged by the effects of frost. Potted hydrangeas are a little more vulnerable due to the small volume of soil: the entire pot may freeze through. Therefore, you should wrap the planter in late autumn with plant fleece or jute bags and, if necessary, place it in a protected place, such as a house wall.

Propagating Oakleaf Hydrangeas

Oakleaf hydrangeas can be propagated from cuttings. These are cut in early summer. Cut off one-year-old, flowerless shoots from the plant and divide them into pieces about 10 to 15 cm long. The leaves are then removed except for the upper pair of leaves and the cuttings are placed at least 5 cm deep in planters filled with seed soil. For example, our nutrient-poor is suitable for this Plantura Organic Herb & Seed Soil, which mixed with at least a third of sand forms the right substrate for the cuttings. The substrate should be moistened daily. In a bright place without direct sunlight and at a temperature of around 15 °C, the cuttings can take root and grow into new young hydrangea plants.

If you would like to find out more about other hydrangea species, you can find out everything about them in our special article panicle hydrangea Experienced.