Bigleaf Hydrangea

Hydrangea macrophylla

Also called french hydrangea, hortensia, mophead hydrangea, lacecap hydrangea and big leaf hydrangea

Also comes in pink.

Bigleaf Hydrangea blooms from June through September.

Bloom calendar

Bloom time

Jun–Sep

Hardiness

Zones 5–9

Sun

Part sun

Water

High water

Mature size

4.9 ft × 4.9 ft

Type

Shrub

Verification

Core facts checked

Mature size, hardiness zones, sun and the trait tags were checked against named botanical sources for this plant. The bloom months and water need on this page were not.

Plant it in part sun. It prefers high water. It is hardy in USDA zones 5–9. Expect it to reach about 4.9 ft tall and 4.9 ft wide at maturity, in roughly 4 years.

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When to plant Bigleaf Hydrangea

Plant Bigleaf Hydrangea in early spring as soon as the soil is workable, or in early fall at least six weeks before your first frost, so roots establish in cool weather. For the middle of its hardy zones 5 to 9 range, spring means March to May and fall means September or October. Once settled, it blooms from June to September.

Month-by-month timing for your zone is on the planting calendar: for the middle of its range, start with zone 7 in March.

7 more varieties in the Hydrangeas family

Same family, similar care - pick the one you are growing.

Good to know about Bigleaf Hydrangea

Curated from university extensions, botanic gardens and other primary sources, with the source named on every note.

Safety

Toxic to dogs, cats and horses; the leaves and buds hold a cyanogenic glycoside. Eating it mostly causes vomiting and diarrhea. per ASPCA

Worth knowing

Flower color really tracks aluminum, not pH. Soil pH matters only because it decides whether the roots can take up aluminum; without it, flowers stay pink. per NC State

When to prune

Old-wood mopheads and lacecaps: prune right after flowering, before about August 1. Reblooming cultivars flower on old and new wood, so prune them in spring. per University of Maryland

How to change color

Acidic soil (pH 5.0 to 5.5) turns flowers blue; alkaline soil (pH 6.0 and up) turns them pink. Sulfur for blue, lime for pink; it takes months. per Clemson

White cultivars stay white

White hydrangeas stay white at any soil pH: they never make the pigment the color change needs, so amending the soil only risks nutrient problems. per Mississippi State

Buds are cold-tender

The roots are winter-hardy but the flower buds are not. Winter cold, drying wind or a late spring freeze can cost you next year's bloom. per NC State

Siting fights two diseases

Two leaf diseases pull opposite ways: powdery mildew is worse in deep shade, Cercospora leaf spot worse in full sun. Morning sun with afternoon shade fights both. per UConn

What pairs well with Bigleaf Hydrangea

Good companions share its growing conditions and add something it lacks: an earlier or later bloom, a lower carpet in front, or structure through winter.

Bugleweed
Takes part sun to part shade and moderate to high water; opens in mid spring and overlaps into this one's season; low at 6 in, to carpet the ground beneath; evergreen, so the bed keeps its shape through winter.
Primrose
Takes part sun to part shade and moderate to high water; blooms in early spring, before this one opens; low at 8 in, to carpet the ground beneath; both offer pollinator forage, in different months.
Aster
Takes full sun to part sun and moderate to high water; overlaps, then carries the display into mid fall; its seed heads stand through winter, for structure and the birds; both offer pollinator forage.
Autumn Crocus
Takes full sun to part sun and moderate to high water; overlaps, then carries the display into mid fall; low at 6 in, to carpet the ground beneath; purple sits close to blue on the wheel.
Pansy
Shares part sun and moderate to high water; opens in early spring and overlaps into this one's season; low at 8 in, to carpet the ground beneath; purple sits close to blue on the wheel.
Hyacinth
Takes full sun to part sun and moderate to high water; blooms in early spring, before this one opens; lower at 10 in, for the front of the border; both offer pollinator forage, in different months.
Flowering Crabapple
Takes full sun to part sun and moderate to high water; blooms in mid spring, before this one opens; both offer pollinator forage, in different months; taller at 20 ft, for the layer behind it.
Sweet Alyssum
Takes full sun to part sun and moderate to high water; low at 5 in, to carpet the ground beneath; both offer pollinator forage; its white flowers settle the blue.