PeeGee hydrangea

Sun

Full sun to partial shade. Give it afternoon shade in hot climates; in cooler regions, more sun usually produces stronger flowering.

Water

Keep the root zone evenly moist but not waterlogged. Water deeply during dry spells, especially during the first two growing seasons and while flower heads are developing.

Soil

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

Height

10-20 ft (3-6 m)

Spread

8-15 ft (2.4-4.6 m)

Flowers

Mid- to late summer into autumn; large, dense, cone-shaped heads open creamy white, age pink and finally dry to tan. Pink colouring varies with weather and growing conditions.

Foliage

Broad, pointed green leaves with toothed edges; autumn colour is usually modest, sometimes yellow.

Growth

Moderate to fast once established.

Care needed

Medium

• Cold hardy
• Wildlife
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Moderate

Toughness

Fairly tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1.8 ft (0.54 m)

2. After 1 year

   5 ft (1.5 m)

3. After 2 years

   8 ft (2.5 m)

4. After 3 years

   12 ft (3.5 m)

5. After 5 years

   15 ft (4.5 m)

   full size

About 4 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Toxic

Growth rate

Fast

• Water deeply when the upper soil begins to dry; do not let newly planted shrubs repeatedly wilt.
• Spread 2-3 in (5-8 cm) of organic mulch over the root zone, keeping it clear of the stems.
• Apply a light dressing of balanced shrub fertiliser in spring only if growth is weak or the soil is poor; excess nitrogen encourages floppy growth.
• Allow space for the mature crown rather than repeatedly cutting it back to fit a narrow bed.
• Stake a newly planted tree-trained specimen until its trunk is stable, and remove shoots that develop below the crown.

Pruning. In late winter or early spring, remove dead, damaged and crossing branches, then shorten last year's shoots as needed to maintain a strong framework; flowers form on new growth. Avoid severe annual cutting, which can produce oversized flower heads on weak stems.

Late winter

Prune before new growth starts, retaining sturdy main branches to support the heavy flowers.

Spring

Plant when the soil is workable, water thoroughly and mulch the root zone.

Late spring

Check tree-trained plants for shoots below the crown and remove them promptly.

Summer

Water deeply during dry periods, checking soil beneath the mulch rather than relying on surface appearance.

Autumn

Leave fading flower heads for winter structure, or remove them if they weigh branches down.

Winter

Where heavy snow is common, remove large dried flower heads before snowfall to reduce branch breakage.

• Use at the back of a deep mixed border, with lower perennials hiding its bare lower stems.
• Plant as a loose flowering screen where its full mature width can develop.
• Train as a small specimen tree beside a lawn or broad path, leaving clearance for arching flower-laden branches.
• Combine with dark evergreen shrubs to make the white and pink flower heads stand out.
• Use in a white garden with hostas and Japanese forest grass in lightly shaded positions.

Garden styles it suits: English country, Traditional, Cottage garden, Romantic rose garden, White garden and Winter interest.

Plant it with: Hostas, Japanese forest grass, Astilbes, Japanese anemones and Black-eyed Susans.

Wildlife: The dense heads consist mostly of showy sterile flowers, so this cultivar offers less nectar and pollen than open-headed panicle hydrangeas with more fertile flowers. Its branches provide cover for small birds.

• Flopping or broken branches: heavy flower heads can overwhelm weak growth; avoid excessive feeding and hard pruning, and retain a sturdy framework.
• Wilting and scorched leaf edges: check soil moisture and water deeply; provide afternoon shade in hot sites rather than allowing repeated drought stress.
• Powdery mildew or leaf spots: improve air circulation, water at soil level and remove fallen infected leaves; minor late-season damage rarely needs treatment.
• Aphids: wash small colonies off young shoots with water; if persistent, use an insecticidal soap labelled for ornamental shrubs.

Toxic if eaten by cats, dogs, horses or people. All parts contain cyanogenic compounds, with leaves and flower buds a particular concern; ingestion usually causes digestive upset, while serious poisoning is uncommon but possible after substantial ingestion. Contact a veterinarian or poison service if any is eaten.

• Limelight hydrangea (Hydrangea paniculata 'Limelight')

  Its flower heads usually open distinctly lime green before becoming cream and pink; 'Grandiflora' opens creamy white and generally develops a larger, looser overall shrub.

• Annabelle smooth hydrangea (Hydrangea arborescens 'Annabelle')

  It has rounded, ball-shaped white flower heads rather than cones and forms a shorter, often suckering shrub.

• Bigleaf hydrangea (Hydrangea macrophylla)

  It usually has broader, thicker leaves and rounded mophead or flat lacecap flowers; many cultivars have pink or blue flowers influenced by soil chemistry.

PeeGee comes from the initials of paniculata 'Grandiflora', while paniculata refers to the branched flower clusters and Grandiflora means large-flowered.

Propagation. Take softwood cuttings in late spring or early summer, or layer a low branch. Vegetative propagation preserves 'Grandiflora'; seedlings will not reliably match it.

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.