Hydrangea Care in South Carolina

Blue flower color of bigleaf hydrangea (Hydrangea macrophylla) occurs in acidic soil.
Joey Williamson, ©2008 HGIC, Clemson Extension

Quick Guide to Growing Bigleaf Hydrangea (Hydrangea macrophylla)

Plant Type: Deciduous flowering shrub
Height & Spread: 4 to 12 feet tall (varies by variety)
Light Requirements: Partial shade; morning sun with afternoon shade; avoid hot, exposed sites
Soil Requirements: Moist, well-drained soil rich in organic matter
Flower Colors: Blue in acidic soil; pink in alkaline soil
Soil pH Targets: 5.0 to 5.5 for blue flowers; 6.0 and up for pink flowers
Watering: High; water deeply once per week or more in heat
Fertilization: Light applications in March, May, & July (10-10-10)
Pruning Time: After flowering; avoid pruning after August 1
Uses: Foundation plantings, borders, containers, mass plantings

How to Grow Bigleaf Hydrangeas (Hydrangea macrophylla) in South Carolina

Hydrangea macrophylla, also called bigleaf or French hydrangea, typically has either pink or blue flowers, although a few cultivars have white flowers. Flower color is determined indirectly by the soil pH, which affects the availability of aluminum in the soil.

In acidic soil (pH 5.0 to 5.5), where aluminum is readily available, the flowers are blue, while in alkaline soils (pH 6.0 and up), they are pink. Research has determined that the actual mechanism of color variation is due to the presence or absence of aluminum compounds in the flowers.

How to Change Hydrangea Flower Color with Soil pH

Flower color is one of the most distinctive and controllable traits of bigleaf hydrangeas.

1. For blue flowers, maintain soil pH 5.0 to 5.5 (acidic) using sulfur or aluminum sulfate when new growth emerges in April.
2. For pink flowers, maintain soil pH 6.0 or higher (alkaline) using lime.

Tip: Always test your soil before applying sulfur or lime to avoid over-correction.

For application rates, refer to the tables in HGIC 1650, Changing the pH of Your Soil. Information on soil testing is available in HGIC 1652, Soil Testing.

Growth habit of bigleaf hydrangea (Hydrangea macrophylla).
Joey Williamson, ©2008 HGIC, Clemson Extension

Hydrangea Size, Growth Rate, & Landscape Uses

Bigleaf hydrangeas add long-lasting summer color and structure to South Carolina landscapes.

Hydrangeas are deciduous shrubs that grow from 4 to 12 feet in height, depending on the variety.

The growth rate of bigleaf hydrangea is relatively fast, making it a good choice for gardeners seeking quick results.

Bigleaf hydrangeas are versatile landscape plants and are effective when used:

• As single focal plants
• In mass plantings for bold color
• In containers on patios or terraces

Best Soil & Planting Tips for Hydrangeas

Hydrangeas are easy to grow in well-drained soil rich in organic matter or humus. Bigleaf hydrangea prefers morning sun and afternoon shade. Avoid planting in hot, dry, exposed sites.

Although most people purchase hydrangeas while they are in bloom, spring or fall is the best time to plant them.

When planting:

1. Dig a hole two to three times as wide as the root ball but no deeper than its height.
2. Backfill the root ball with the native soil removed from the hole.
3. Maintain a 2 to 3-inch mulch layer to retain soil moisture and moderate temperature.
4. Water thoroughly after planting.

Test soil pH every 2 to 3 years to maintain desired bloom color and nutrient balance.

How to Fertilize Hydrangeas

Regular fertilization promotes strong stems, vibrant blooms, and consistent color formation. Bigleaf hydrangeas respond well to light fertilizer applications during the growing season.

• Use a balanced fertilizer such as 10-10-10 (10% nitrogen, 10% phosphorus, 10% potassium).
• Apply at a rate of 2 cups per 100 sq ft in March, May, and July.
• Water immediately after fertilizing to move nutrients into the soil.
• It is not necessary to remove mulch before applying fertilizer.

Bigleaf hydrangeas (Hydrangea macrophylla) need ample moisture and afternoon shade to prevent wilting.
Karen Russ, ©2008 HGIC, Clemson Extension

Watering Considerations for Hydrangeas

Consistent watering is essential for preventing leaf scorch and maintaining bloom quality. Hydrangeas have large leaves that lose moisture quickly. Plants can suffer if set out during hot summer weather.

• Water deeply once per week, or more often during dry conditions.
• Maintain consistent moisture to prevent wilting and flower loss.

In South Carolina’s summer heat, hydrangeas often require deep watering twice weekly in sandy soils.

Tip: Drip irrigation reduces water waste and helps prevent leaf disease.

When & How to Prune Bigleaf Hydrangeas for More Blooms

Prune after flowering to allow the development of “old wood” that supports next summer’s blooms.

• Avoid pruning after August 1 to prevent removing next year’s buds.
• Use clean, sharp bypass pruners to reduce disease spread.
• Disinfect pruners between cuts to prevent disease transmission.

Proper pruning timing is key to maintaining next year’s blooms—hydrangeas flower on old wood.

Propagation Methods: Layering & Division

Hydrangeas propagate easily through layering or dividing mature clumps, making them ideal for expanding your garden naturally.

Layering Method

1. Dig a shallow trench near the parent plant.
2. Bend a flexible limb into the trench.
3. Remove a 1-inch ring of bark around the buried section.
4. Cover with soil, leaving 6 to 12 inches of tip growth exposed.

Dividing Mature Clumps

• In early spring, use a shovel to divide old established clumps into smaller plants.

Common Problems, Diseases & Pests of Hydrangeas

Why Hydrangeas Fail to Bloom

The most common reason hydrangeas fail to bloom is winter injury. Other possible causes include:

• Too much shade
• Poor soil fertility
• Excess nitrogen fertilizer

Fungal Leaf Diseases on Hydrangea

Hydrangeas are susceptible to Cercospora leaf spot, anthracnose, and powdery mildew.

To reduce fungal pressure:

• Remove and dispose of fallen leaves each season.
• Use drip irrigation or soaker hoses to keep foliage dry.
• If using sprinklers, water early in the morning so leaves dry quickly.

Fungicide Control Options

For cultural and chemical management:

• Cercospora Leaf Spot Control – Spray every 2 weeks with chlorothalonil, thiophanate methyl, mancozeb, or myclobutanil.
• Managing Anthracnose – Spray every 2 weeks with chlorothalonil or thiophanate methyl.
• Preventing Powdery Mildew – Spray weekly with 1% horticultural oil, or every 2 weeks with thiophanate methyl or myclobutanil.

Insect Pests on Hydrangea

Common insect pests include:

• Aphids – often on tender shoots
• Hydrangea leaftiers – webbing leaves together
• Rose chafers – chewing damage on foliage and flowers

See Table 1 for examples of pesticide brands and products available to homeowners in South Carolina. Always follow label instructions for safe pesticide use.

Table 1. Fungicide Products for Hydrangea Disease Control in the Landscape.

Cercospora leaf spots (Cercospora hydrangea) with purple margins and tan centers on bigleaf hydrangea.
Joey Williamson, ©2014 HGIC, Clemson Extension

The larger, necrotic (brown) areas are caused by anthracnose, a disease brought on by Colletotrichum gloeosporioides, on bigleaf hydrangea.
Joey Williamson, ©2014 HGIC, Clemson Extension

Best Hydrangea Varieties for South Carolina Landscapes

Each hydrangea species thrives in slightly different growing conditions, from full sun to deep shade. Different hydrangea species offer unique bloom forms, leaf textures, and seasonal color changes.

Variegated foliage variety of bigleaf hydrangea (Hydrangea macrophylla).
Joey Williamson, ©2008 HGIC, Clemson Extension

Bigleaf Hydrangea (H. macrophylla)

The cultivars of Hydrangea macrophylla are divided into two main groups:

1. Hortensias (Mophead Types) – Sterile flowers form solid masses, often heavy enough to bend the stems.

Hortensias Cultivars:

• ‘All Summer Beauty‘ – 3 to 4 feet tall; flower heads produced on current season’s growth (reblooming type).
• ‘Carmen‘ – 4 feet tall; large pink flower heads.
• ‘Nikko Blue‘ – 4 to 6 feet tall; rich blue flower heads (in acid soil).
• ‘Blue Prince‘ – 3 to 5 feet tall; sky blue flower heads.
• ‘Compacta‘ – More compact than ‘Nikko Blue’ with darker green foliage.

2. Lacecaps – A center of fertile, non-showy flowers surrounded by a ring of showy, sterile flowers creating a pinwheel effect.

Lacecaps Cultivars:

• ‘Blue Wave‘ – 6 to 7 feet tall with lacecap flowers.
• ‘Coerulea‘ – Deep blue fertile flowers with blue or white outer rays.
• Variegated Lacecaps – Cultivars such as ‘Quadricolor,’ ‘Silver Variegated Mariesii,’ and ‘Variegata’ feature silver or creamy variegated foliage for added ornamental appeal.

Climbing Hydrangea (H. anomala):

This deciduous vine climbs high using aerial rootlets that cling to walls or trees.

• Leaves: Roundish, 2 to 4 inches long
• Flowers: White clusters 6 to 10 inches wide in lacecap form
• Bark: Older stems develop peeling, cinnamon-colored bark

Oakleaf Hydrangea (H. quercifolia):

This deciduous shrub grows to approximately 6 feet tall, featuring deeply lobed, oak-like leaves that can reach up to 8 inches in length.

Leaves turn bronze in the fall.

• Flowers: White, turning pinkish with age
• Notable cultivars:
  • ‘Snow Queen’ – Large white flower clusters
  • ‘Snowflake’ – Double-flowered form
  • ‘Harmony’ – 3 ft tall × 6 ft wide; produces spectacular 12-inch cones of sterile flowers

A double-flowered oakleaf hydrangea (Hydrangea quercifolia).
Joey Williamson, ©2008 HGIC, Clemson Extension

Oakleaf hydrangea (Hydrangea quercifolia) fall color
Karen Russ, ©2008 HGIC, Clemson Extension

Smooth Hydrangea / Snowhill Hydrangea (H. arborescens)

This 5-foot-tall deciduous shrub has oval, grayish-green leaves (4 to 8 inches long).

• Flowers: Dull white, blooming late June through September
• Cultivars:
  • ‘Annabelle’ – Enormous 12-inch globes of sterile white flowers, 4 ft tall.
  • ‘Grandiflora’ – 6-inch flower clusters on a similar-sized plant.

Peegee Hydrangea (H. paniculata):

A larger hydrangea that can grow as a 10 to 15 ft shrub or a 25 ft small tree.

• Leaves: About 5 inches long, turning bronze in fall
• Flowers: 10 to 15 inch clusters, white fading to pink in autumn
• Excellent tolerance for urban and seaside conditions
• Cultivars:
  • ‘Tardiva’ – Late blooming (August–September)
  • ‘Praecox’ – Early blooming (June)

Flowers of smooth hydrangea (Hydrangea arborescens).
Joey Williamson, ©2008 HGIC, Clemson Extension

Peegee hydrangea (Hydrangea paniculata) flowering with white blooms in late summer.
Karen Russ, ©2008 HGIC, Clemson Extension

Lacecap-type flowers of Hydrangea serrata ‘Bluebird’
Joey Williamson, ©2008 HGIC, Clemson Extension

Mountain Hydrangea (H. serrata)

A compact shrub (to 5 ft tall) similar to H. macrophylla, but with smaller leaves and blooms.

• Foliage: Fine-textured and smaller than bigleaf types
• Cultivar Highlight: ‘Blue Billow’ – Only 3 ft tall with rich blue lacecap flowers

Pesticides are updated annually. Last updates were done on 08/24 by Jordan Franklin.

Document last updated on 10/25 by Jordan Franklin.

Originally published 04/02