Oakleaf hydrangea

Sun

Partial shade, ideally morning sun and afternoon shade. Tolerates full sun in cooler climates if the soil stays moist; provide afternoon shade in hot regions.

Water

Keep evenly moist while establishing. Established shrubs tolerate short dry spells, but water deeply during prolonged drought, especially in sunny positions.

Soil

Humus-rich, well-drained soil, preferably slightly acidic to neutral. Avoid waterlogged ground; flower colour does not turn blue with acidic soil.

Height

6-8 ft (1.8-2.4 m)

Spread

6-8 ft (1.8-2.4 m)

Flowers

Late spring to midsummer, depending on climate. Conical clusters open white, often age pink, then dry to tan or brown.

Foliage

Large, deeply lobed green leaves with softly hairy undersides; turns red, burgundy or purple in autumn, with colour varying by climate and position.

Growth

Moderate; may gradually form a wider clump through suckering.

Care needed

Low

• Water deeply during dry weather for the first two growing seasons; check the root ball rather than relying on surface dampness.
• Apply 2-3 in (5-8 cm) of organic mulch, keeping it clear of the stems.
• Top-dress with compost in spring; use a modest amount of balanced shrub fertiliser only if growth is poor.
• Allow room for its mature width rather than repeatedly clipping it to fit.
• Remove unwanted suckers at their point of origin if you need to contain the clump.

Pruning. Flowers form on old wood, so prune only if needed, immediately after flowering, shortening wayward stems to a healthy pair of buds. Remove dead wood in spring once live buds are visible; avoid routine autumn or winter cutting, which removes the next flower crop.

Spring

Plant once the soil is workable, water thoroughly and mulch; avoid planting into saturated ground.

Mid-spring

Check emerging buds before removing dead or winter-damaged stems.

Late spring

Top-dress with compost and check soil moisture as leafy growth develops.

Summer

Water deeply during extended dry spells, particularly around newly planted shrubs.

After flowering

Do any necessary shaping promptly; leave some flower heads for autumn and winter interest.

Autumn

Plant in mild regions while the soil is warm and moist; remove badly spotted fallen leaves.

• Plant along a woodland edge with ferns and sedges, using its broad leaves to contrast with finer foliage.
• Use in a mixed shrub border for white summer flowers followed by strong autumn colour.
• Group several shrubs as an informal screen in partial shade, allowing enough width for their spreading branches.
• Place where winter light catches the peeling bark and dried flower heads.

Garden styles it suits: Woodland, Southern, English country, Autumn colour, Winter interest and Low-maintenance.

Plant it with: Christmas fern, Japanese painted fern, Hosta, Coral bells, Virginia sweetspire and Pennsylvania sedge.

Wildlife: The small fertile flowers provide pollen and nectar for visiting insects, though cultivars with mostly sterile flowers offer less. Dense branches provide cover for small birds.

• Few or no flowers: winter-damaged buds, late pruning or deep shade are common causes. Preserve old stems, prune only after flowering and choose a sheltered position with some sun.
• Root rot in wet soil: improve drainage or move the shrub to a raised planting area; do not keep the root zone constantly saturated.
• Leaf spots or powdery mildew: allow space for airflow, water at soil level and clear affected fallen leaves. Mild late-season damage usually needs no treatment.
• Scorched or wilting leaves: check soil moisture and water deeply if dry; provide afternoon shade in hot climates rather than repeatedly giving shallow drinks.

Toxic if eaten by cats, dogs, horses or people. Leaves, buds, flowers and other parts contain cyanogenic compounds; ingestion most often causes vomiting, diarrhoea or abdominal discomfort, while serious poisoning is uncommon. Keep clippings away from livestock and seek veterinary or medical advice after ingestion.

• Panicle hydrangea (Hydrangea paniculata)

  Also has cone-shaped flower clusters, but its leaves are oval and unlobed. It flowers on new growth rather than old wood.

• Bigleaf hydrangea (Hydrangea macrophylla)

  Has broad, unlobed leaves and rounded mophead or flatter lacecap flower clusters, rather than oak-shaped leaves and elongated cones.

• Smooth hydrangea (Hydrangea arborescens)

  Has unlobed, oval to heart-shaped leaves and rounded or flattened flower clusters. It lacks the distinctive oak-like foliage.

The epithet quercifolia means oak-leaved, referring to the lobed leaves that also give oakleaf hydrangea its common name.

Propagation. Take softwood cuttings in early summer, layer a low branch, or lift rooted suckers during dormancy. Seed-grown plants may differ from the parent; use vegetative propagation to preserve a named cultivar.

Accepted botanical name

Hydrangea quercifolia

In the US and Canada

Native in the lower 48 states.

Native range

Alabama, Florida, Georgia, Louisiana, Mississippi, South Carolina and Tennessee.

Measured

Soil pH 4.6 to 7.5. Average height 183 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.