Panicle hydrangea

Sun

Full sun to partial shade. Give it afternoon shade in hot climates; in cooler climates, more sun generally produces better flowering.

Water

Keep the root zone evenly moist, especially during establishment and hot weather. Established plants tolerate brief dry spells, but prolonged drought reduces flowering and can scorch leaves.

Soil

Moist, well-drained soil enriched with organic matter; tolerates clay if drainage is adequate. Grows in mildly acidic to mildly alkaline soil, and flower colour is not controlled by soil pH.

Height

8-15 ft (2.4-4.6 m), sometimes taller; compact cultivars are much smaller

Spread

6-12 ft (1.8-3.7 m), depending on cultivar

Flowers

Summer into autumn; cone-shaped clusters open white or cream, often developing pink tones before drying tan. Colour changes vary with cultivar and climate.

Foliage

Broad, pointed green leaves with toothed edges, arranged in opposite pairs or groups of three; autumn colour is usually modest.

Growth

Moderate to fast once established.

Care needed

Low

• Water deeply during dry spells for the first two growing seasons, wetting the soil across the root zone.
• Apply 2-3 in (5-8 cm) of organic mulch, keeping it clear of the stems.
• In spring, top-dress with compost; use a modest application of balanced fertiliser only if growth is weak or soil is poor.
• Avoid heavy nitrogen feeding, which encourages leafy growth and weak stems.
• Choose a cultivar that fits the space rather than relying on severe annual pruning.

Pruning. In late winter or early spring, remove dead, damaged and crossing stems, then shorten the previous year's growth as needed to shape the shrub. Hard pruning produces fewer, larger flower heads that may flop; lighter pruning usually gives more flowers on a stronger framework.

Late winter

Remove dead or damaged wood and prune for shape before new growth begins.

Spring

Plant while the soil is workable, water thoroughly and renew the mulch.

Late spring

Check new plants regularly for dry soil and water deeply when needed.

Summer

Water during prolonged dry weather and check leaf undersides if foliage becomes stippled.

Autumn

Leave drying flower heads for seasonal interest, or cut a few for indoor arrangements.

Winter

If heavy snow regularly bends or breaks branches, remove the dried flower heads.

• Use as a flowering backdrop in mixed borders with coneflowers, catmint and ornamental grasses.
• Plant a loose flowering hedge along a boundary, allowing room for the mature spread.
• Place a compact cultivar near a terrace or entrance for late-season flowers without blocking access.
• Combine with white-flowered perennials and dark evergreens for contrast and interest into autumn.

Garden styles it suits: English country, Cottage garden, Traditional, New perennial (prairie), White garden and Autumn colour.

Plant it with: Catmint, Coneflower, Black-eyed Susan, Feather reed grass, Japanese anemone and Hosta.

Wildlife: Fertile flowers provide pollen and nectar for visiting insects. Open, lace-like flower clusters generally offer more accessible food than dense heads dominated by showy sterile florets; the shrub also provides cover for small birds.

• Wilting or brown leaf edges: check soil moisture and water deeply if dry; provide afternoon shade in hot sites and avoid waterlogged ground.
• Flopping flower heads: reduce severe pruning and nitrogen feeding; choose a sturdy-stemmed cultivar for exposed positions.
• Powdery mildew or leaf spots: improve airflow, water the soil rather than the leaves and remove badly affected fallen foliage.
• Spider mites in hot, dry weather: look for fine stippling and webbing, rinse leaf undersides and avoid broad-spectrum insecticides.

Toxic to cats, dogs, horses and people if eaten. All parts contain cyanogenic glycosides, particularly leaves and flower buds. Ingestion most often causes digestive upset; serious poisoning is uncommon but possible, so contact a veterinarian or poison service if any is eaten.

• Smooth hydrangea (Hydrangea arborescens)

  Usually has rounded or flattened flower heads rather than long cones, with broader, often heart-based leaves.

• Oakleaf hydrangea (Hydrangea quercifolia)

  Also bears cone-shaped flower clusters, but its large, deeply lobed leaves resemble oak leaves and often develop strong autumn colour.

• Bigleaf hydrangea (Hydrangea macrophylla)

  Has rounded mophead or flat lacecap flowers and generally thicker, glossier leaves; many cultivars develop pink or blue flowers according to soil conditions.

Hydrangea comes from Greek words meaning water vessel, referring to the seed capsules, while paniculata refers to the branched, cone-shaped flower clusters called panicles.

Propagation. Take softwood cuttings in late spring or early summer, or layer a low branch. Seed-grown plants vary and will not reliably match a named cultivar; check local plant breeders' rights or patent restrictions before propagating protected cultivars.

Accepted botanical name

Hydrangea paniculata

In the US and Canada

Introduced in Canada and the lower 48 states.

Native range

China North-Central, China South-Central, China Southeast, Japan, Kuril Is., Sakhalin and Taiwan.

Measured

Average height 580 cm.

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