Bigleaf Hydrangea (Hydrangea macrophylla) care guide

Bigleaf Hydrangea is the common name for Hydrangea macrophylla, a deciduous shrub grown for its large mophead or lacecap flower clusters. It belongs to the Hydrangeaceae family and is widely grown in U.S. gardens.

Give Bigleaf Hydrangea morning sun and afternoon shade for the best balance of flowering and moisture retention. In cooler climates it may tolerate more sun, while hot afternoon sun can scorch leaves and shorten bloom life.

Water Hydrangea macrophylla whenever the soil surface begins to dry, keeping the root zone evenly moist but not waterlogged. During hot or dry weather, it may need deep watering several times per week.

Plant Bigleaf Hydrangea in organic-rich, moisture-retentive, well-drained soil. Heavy clay or very sandy soil should be improved with organic matter, but avoid sites where water remains around the roots.

Hydrangea macrophylla commonly grows about 3 to 6 feet tall and wide, although mature size varies substantially by cultivar and growing conditions. Check the plant label for the specific variety’s expected dimensions.

Bigleaf Hydrangea can grow in full sun if the climate is mild and the soil stays consistently moist, but afternoon shade is usually safer. Full, hot sun increases the risk of wilting, leaf scorch, and reduced flowering.

Many Hydrangea macrophylla cultivars grow best in USDA Zones 5 through 9, but hardiness varies by cultivar. In colder areas, winter protection is important because flower buds on older stems are vulnerable to freezing.

Yes, Bigleaf Hydrangea grows well in a large container with drainage holes and moisture-retentive potting mix. Containers dry out and freeze more quickly than garden soil, so they require closer watering and extra winter protection.

Afternoon shade is recommended, especially in hot or humid parts of the United States. Protection from intense afternoon sun helps prevent wilting, scorched leaves, and rapid drying of the soil.

Apply mulch over the root zone and protect the stems from drying wind and severe cold with a loose covering when needed. Winter protection is most important for traditional cultivars that form flower buds on old wood.

The most common causes are winter-killed flower buds, pruning at the wrong time, insufficient light, and excessive nitrogen. Bigleaf Hydrangea often blooms on old wood, so cutting stems in fall, winter, or early spring can remove the next season’s flower buds.

Prune traditional Bigleaf Hydrangea immediately after flowering, removing only weak, damaged, or overcrowded stems as needed. Some reblooming cultivars flower on both old and new wood, but the specific cultivar should be confirmed before making a hard cut.

You may deadhead Hydrangea macrophylla for appearance, preferably soon after the flowers fade. Cut just above healthy buds, because late-season removal of stems can eliminate flower buds formed for the following year.

Brown leaves are commonly caused by drought stress, hot afternoon sun, wind, or fertilizer injury. Keep the soil evenly moist, provide afternoon shade, and avoid applying concentrated fertilizer to dry soil.

Wilting usually indicates water stress or heat stress, especially when the plant receives intense afternoon sun. Check the soil before watering; if it is moist and the plant recovers in the evening, temporary heat stress may be the cause.

Fertilize Bigleaf Hydrangea lightly in spring with a balanced, slow-release fertilizer if growth is weak or soil fertility is low. Avoid heavy nitrogen applications, which can produce leafy growth at the expense of flowers.

Common pests include aphids, scale, spider mites, and Japanese beetles, while slugs may damage young foliage. Inspect leaves regularly and use the least-toxic control appropriate for the pest and severity of the damage.

Bigleaf Hydrangea can develop leaf spot, powdery mildew, gray mold, or root problems in persistently wet conditions. Improve air circulation, water at the soil line, remove severely affected leaves, and correct poor drainage.

Plant Hydrangea macrophylla in spring or fall when temperatures are moderate and the soil is workable. Spring planting is preferable in colder areas because it gives the roots more time to establish before winter.

Dig a hole about twice as wide as the root ball and no deeper than the existing soil level, then backfill with the native soil improved with organic matter. Water thoroughly and apply a 2- to 3-inch layer of mulch without touching the stems.

Space Bigleaf Hydrangeas according to their mature width, commonly about 3 to 6 feet apart. Allow additional room for large cultivars and provide enough air circulation to reduce foliar disease.

Yes, transplant Hydrangea macrophylla during dormancy in early spring or fall, keeping as much of the root ball intact as possible. Water consistently after transplanting because temporary root loss can cause wilting.

Yes, Hydrangea macrophylla tolerates and often performs well in moderately acidic soil. Soil pH also affects flower color in many cultivars, but it should be tested before applying amendments.

Take softwood cuttings in late spring or early summer, remove the lower leaves, and place the cuttings in a sterile, consistently moist rooting medium. Rooting success varies by cultivar, so use several cuttings rather than relying on one.

Yes, layering is a practical way to propagate Hydrangea macrophylla. Bend a low, flexible stem to the soil, lightly wound or pin part of it beneath the soil, and separate the rooted section after it develops a strong root system.

Yes, Bigleaf Hydrangea is considered toxic to dogs, cats, and horses if chewed or swallowed. Keep pets from eating the plant and contact a veterinarian or animal poison service if ingestion occurs.

Hydrangea macrophylla is moderately toxic if chewed or swallowed and may cause gastrointestinal upset. Keep leaves, flowers, and plant parts away from children, and seek medical advice if a significant amount is ingested.

Blue flowers are more likely when the soil is acidic and aluminum is available to the plant, but cultivar genetics also matter. Test the soil before using an acidifying or aluminum-containing amendment, and do not expect reliable color changes in every cultivar.

Pink flowers are favored by less-acidic or alkaline soil, although the result depends on the cultivar and available soil minerals. A soil test should guide any amendment, because changing pH too aggressively can harm the plant or nearby plants.

Most white-flowered Bigleaf Hydrangea cultivars do not turn blue or pink simply because soil pH changes. Some flowers may age to green, pink, or burgundy depending on the cultivar and weather.

Bigleaf Hydrangea generally blooms from late spring through summer, with timing varying by cultivar and climate. Reblooming cultivars may produce additional flowers later in the season on new growth.

Mophead cultivars have rounded clusters made mostly of showy sterile florets, while lacecaps have a flatter arrangement with larger sterile florets around smaller fertile flowers. Both forms belong to Hydrangea macrophylla and have similar basic care needs.