Complete Guide to Growing & Caring for Bigleaf Hydrangeas (Hydrangea Macrophylla)

Bigleaf hydrangeas (Hydrangea macrophylla) are beloved garden shrubs known for their spectacular blooms and remarkable ability to change flower color based on soil conditions. Whether you’re looking to add a splash of blue, pink, or purple to your landscape, these versatile plants offer long-lasting beauty from summer through fall. This comprehensive guide covers everything you need to know about successfully growing and caring for these stunning garden favorites.

About Bigleaf Hydrangeas

Bigleaf hydrangeas, also known as mophead or lacecap hydrangeas, are the quintessential Southern garden shrub that has gained popularity across many growing zones. With their large, glossy leaves and impressive flower heads, these plants make a bold statement in any garden setting. They’re versatile enough to be used as specimen plants, in mixed borders, or even in containers on a patio or deck.

Native to Japan, Hydrangea macrophylla has become a garden staple worldwide, with countless cultivars offering variations in size, bloom type, and color. What makes these hydrangeas particularly special is their chameleon-like ability to change flower color based on the soil’s pH level—a unique characteristic that fascinates gardeners of all experience levels.

Types of Bigleaf Hydrangeas

Bigleaf hydrangeas come in two main types, each offering distinct flower forms:

Mophead Hydrangeas

Mophead varieties feature large, rounded flower clusters comprised of showy florets that create a ball-like appearance. These are the classic hydrangeas most people envision, with dense blooms that can reach 6-8 inches in diameter. Varieties like ‘Big Daddy’ and ‘Nikko Blue’ exemplify the dramatic impact mophead hydrangeas can have in the landscape.

Lacecap Hydrangeas

Lacecap varieties display a more delicate, flattened flower head with small fertile florets in the center surrounded by a ring of showier sterile florets. This creates an elegant, lace-like appearance that adds a touch of sophistication to the garden. Popular lacecap varieties include ‘Blue Wave’ and ‘Light-O-Day’.

Planting Bigleaf Hydrangeas

Proper planting is crucial for the long-term success of your bigleaf hydrangeas. Taking the time to select the right location and prepare the soil will reward you with healthier plants and more abundant blooms.

When to Plant

The ideal time to plant bigleaf hydrangeas is during milder weather in early spring or fall. This gives the plants time to establish their root systems before facing the stress of extreme summer heat or winter cold. Avoid planting during periods of intense heat or freezing temperatures to prevent shock to the plant.

Where to Plant

Bigleaf hydrangeas thrive in locations that receive morning sun and afternoon shade, especially in warmer climates. In cooler northern regions, they can tolerate more sun as long as they have consistent moisture. When selecting a planting site, consider the following factors:

• Light requirements: Morning sun with afternoon shade is ideal in most regions
• Protection: Choose a location sheltered from strong winds
• Space: Allow enough room for mature size (typically 3-6 feet tall and wide, depending on variety)
• Drainage: Ensure the site has good drainage while still retaining moisture

How to Plant

Follow these steps for successful planting:

1. Dig a hole twice as wide as the root ball but no deeper than the container
2. Amend native soil with compost or rich organic matter if needed
3. Remove the plant from its container and gently loosen the roots
4. Place the plant in the hole, keeping the top of the root ball level with the soil surface
5. Backfill with soil mixture and firm gently around the base
6. Water thoroughly to eliminate air pockets
7. Apply 2-3 inches of mulch around the base, keeping it away from the stems

Hydrangea Macrophylla Features

Flowers

The most captivating feature of bigleaf hydrangeas is undoubtedly their spectacular blooms. These large showy flower heads are comprised of clusters of smaller florets and have either a rounded mophead or flat lacecap appearance. Flower colors typically range from pink to blue, depending on soil pH, but can also include white, purple, or red varieties.

Hydrangea macrophylla blooms can be solid, bicolored, or multi-colored, with single or double florets. The flowers are exceptionally long-lasting, making them excellent choices for both fresh and dried arrangements. Most traditional varieties bloom on the previous year’s growth (old wood), though newer reblooming varieties like the Endless Summer® series flower on both old and new wood, extending the blooming season.

Foliage

Even when not in bloom, bigleaf hydrangeas offer attractive foliage that provides garden interest. The leaves are typically green or occasionally variegated, with an oval, pointed shape featuring pronounced veining and serrated edges. The foliage is quite substantial, giving the plant a lush appearance throughout the growing season. However, fall color is generally insignificant, as these plants focus their energy on flowering rather than dramatic autumn displays.

Care for Bigleaf Hydrangeas

Soil Requirements

Hydrangea macrophylla prefers moist, well-drained soil rich in organic matter. If your native soil is poor, consider amending it with compost or other organic materials before planting. These hydrangeas perform best in soil with a slightly acidic to neutral pH, though they can adapt to various soil conditions—which will affect their flower color.

Apply several inches of bark mulch or compost around the base of the plant to suppress weeds, retain moisture, and gradually add nutrients to the soil as it breaks down. Reapply mulch each spring as needed. For container-grown bigleaf hydrangeas, use a high-quality all-purpose potting mix and add a layer of mulch on top.

Soil pH and Flower Color

One of the most fascinating aspects of bigleaf hydrangeas is how flower color changes based on soil pH. This color-changing ability applies to many (but not all) varieties. Here’s how soil pH affects bloom color:

White-flowering varieties maintain their color regardless of soil pH. To change your hydrangea’s color, apply soil amendments in early spring and again in fall. Be patient—color changes may take several months to fully develop. Remember that container plants are easier to manipulate for color than those planted in the ground.

Watering

Consistent moisture is crucial for bigleaf hydrangeas, especially during their establishment period and throughout the growing season. Their name “hydrangea” derives from Greek words meaning “water vessel,” highlighting their moisture needs.

Water deeply once or twice weekly, providing about 1 inch of water each time. During hot, dry periods, you may need to increase watering frequency. These plants will signal their thirst by wilting, but try to water before they reach this stress point. Morning watering is preferable to allow foliage to dry before evening, reducing disease risk.

For container-grown plants, check moisture levels more frequently as pots dry out faster than garden soil. Established plants (3+ years) develop deeper root systems and become somewhat more drought-tolerant, though they still prefer consistent moisture.

Fertilizing

Bigleaf hydrangeas benefit from regular fertilization to support healthy growth and abundant blooms. Apply a balanced, slow-release fertilizer formulated for flowering shrubs in early spring as new growth begins. A second light application in early summer can support continued flowering.

If you’re adjusting soil for color, use specialized hydrangea fertilizers designed to maintain blue or pink blooms. Avoid high-nitrogen fertilizers that promote lush foliage at the expense of flowers, and never fertilize after August in most regions, as this can stimulate tender new growth vulnerable to fall frosts.

Pruning

Proper pruning is essential for maintaining healthy bigleaf hydrangeas with abundant blooms. The timing and method depend on whether your variety blooms on old wood, new wood, or both:

Traditional Varieties (Old Wood Bloomers)

For varieties that bloom on old wood (last year’s growth):

• Prune immediately after flowering finishes in summer
• Remove no more than one-third of the older stems to ground level
• Cut spent blooms back to first set of healthy buds
• Avoid pruning in fall, winter, or spring as you’ll remove flower buds

Reblooming Varieties (Old and New Wood)

For newer reblooming varieties that flower on both old and new growth:

• Deadhead spent blooms throughout the season to encourage more flowers
• Light pruning can be done almost anytime, though early spring is ideal
• Remove no more than one-third of the plant’s height

Winter Protection

In colder regions (especially zones 5-6), bigleaf hydrangeas may need winter protection to preserve flower buds for the following season. After the first hard frost, apply 3-4 inches of mulch around the base of the plant. In particularly harsh climates, you can create a protective cage around the plant using chicken wire filled with dry leaves, or cover with burlap or frost cloth.

Common Problems and Solutions

While generally robust, bigleaf hydrangeas can encounter several issues:

Pests

Common pests include aphids, spider mites, and scale insects. Regular inspection and treatment with insecticidal soap or horticultural oil can keep these populations in check. Japanese beetles may also feed on foliage; handpick them early in the morning or use appropriate insecticides if infestations are severe.

Diseases

Powdery mildew, leaf spot, and botrytis blight can affect hydrangeas, especially in humid conditions with poor air circulation. Prevent these issues by avoiding overhead watering, ensuring adequate spacing between plants, and promptly removing affected foliage. Fungicides may be necessary in severe cases.

Other Issues

The most common complaint with bigleaf hydrangeas is lack of blooms, typically caused by:

• Improper pruning (cutting off flower buds)
• Winter damage to buds
• Too much shade
• Excessive nitrogen fertilizer

Landscape Uses

Bigleaf hydrangeas are incredibly versatile in the landscape:

• Foundation plantings
• Mixed borders
• Woodland garden edges
• Mass plantings for dramatic effect
• Container specimens for patios and porches
• Cutting gardens for fresh and dried arrangements

Their ability to thrive in partial shade makes them excellent choices for brightening dimmer areas of the garden where other flowering shrubs might struggle.

Frequently Asked Questions

Q: Why isn’t my bigleaf hydrangea blooming?

A: The most common reasons include improper pruning (removing flower buds), winter bud damage, insufficient sunlight, or excessive nitrogen fertilizer. Consider switching to a reblooming variety if winter bud damage is a recurring issue in your climate.

Q: How do I change my hydrangea’s color from pink to blue?

A: To achieve blue flowers, you need acidic soil (pH below 5.5). Apply aluminum sulfate according to package directions in early spring and again in fall. Maintain consistent moisture, as the aluminum needs to be in a soluble form to be absorbed by the plant.

Q: Can bigleaf hydrangeas grow in full shade?

A: While they can survive in full shade, flowering will be significantly reduced. Morning sun with afternoon shade provides the ideal balance for abundant blooms and healthy foliage, especially in warmer climates.

Q: When is the best time to transplant a bigleaf hydrangea?

A: Early spring before new growth emerges or fall after the heat of summer has passed are the best times for transplanting. Water thoroughly before and after moving the plant, and prune back by about one-third to compensate for root loss.

Q: How long do bigleaf hydrangeas live?

A: With proper care, bigleaf hydrangeas can thrive for 50+ years in the garden, making them a long-term investment in your landscape. Many gardeners have specimens that have been passed down through generations.

With their stunning blooms, color-changing abilities, and relatively easy care requirements, bigleaf hydrangeas deserve their place as garden favorites. By understanding their specific needs and providing the right growing conditions, you can enjoy these magnificent flowering shrubs for many years to come.

Author

Anjali Sayee

 

Anjali is an Associate Editor at StyleCraze with 7 years of experience specializing in hairstyles, hair care, and skin care. She has authored over 300 articles and offers expert advice on hair styling techniques, effective skin care routines, and tips for maintaining healthy hair and skin.

Read full bio of Anjali Sayee