Appearance

Growth form

A compact shrub that drops its leaves in fall, usually 2–4 ft (0.6–1.2 m) tall and wide.

Leaves

Oval, dark green leaves up to 6 in (15 cm) long with saw-toothed edges. The name serrata means "toothed."

Flowers

Many plants have flat lacecap clusters, with small seed-producing flowers in the center and larger showy flowers around the edge. Garden selections also include rounded flower heads, and color can vary with soil conditions.

Flowering time

Blooms in summer in North Carolina gardens.

Look-alikes

Bigleaf hydrangeaHydrangea macrophylla

Mountain hydrangea is usually smaller, with thinner stems and smaller leaves. Both species can have flat flower heads, so a round head alone is not a sure sign.

Why they get mixed up · Both come in pink, blue, and white garden forms.

Panicle hydrangeaHydrangea paniculata

Panicle hydrangea has tall, cone-shaped flower clusters. Mountain hydrangea usually has flatter or rounded heads.

Why they get mixed up · Both are planted in U.S. summer gardens.

Where it lives

Typical habitats

• shade gardens
• woodland plantings
• containers

Range

Native to East Asia and grown for its flowers in U.S. gardens, including North Carolina. It is not native to the United States.

Preferred conditions

Hardy in plant hardiness zones 6a–9b. It prefers rich, moist, well-drained soil and part shade.

Life cycle

Reproduction

In a typical lacecap cluster, the small central flowers can set seed while the larger outer flowers are usually sterile.

Cautions

Cautions

It's poisonous to cats, dogs, and horses.

Connected species

Pollinators

The flowers attract bees.

Pollinators

• beesAnthophila

  In U.S. gardens, the flowers attract bees.

Name and classification

About the name

Some botanists treat mountain hydrangea as a subspecies of bigleaf hydrangea (Hydrangea macrophylla), while others keep it as a separate species. Some botanists also separate certain western Japanese plants as Hydrangea acuminata.

Varieties and forms

U.S. gardens grow selections such as 'Blue Billow' and 'Annie’s Blue'. Some plants sold under older mountain-hydrangea names may be hybrids with bigleaf hydrangea.

Conservation

IUCN Red List

NENot Evaluated·Not yet assessed