How to Plant, Grow, and Care For Bigleaf Hydrangeas

Classic beauties of the summertime garden, Hydrangea macrophylla boasts the big, colorful blooms and lush leaves we dream of in the warm season. Bigleaf hydrangeas are the signature bloom of seaside towns, cottage gardens, woodland respites—and everything in between. 

With so many gorgeous varieties available, there’s likely a fitting bigleaf for any dappled garden arrangement. If you have a partially shaded spot, whether in the ground or a container, these long-lived bloomers grace the display with distinctive flowers in shades from pale pink to magenta and periwinkle to violet blue. 

What are Bigleaf Hydrangeas?

Bigleaf hydrangeas feature showy flat-topped lacecap or rounded mophead flower clusters in rich blues, pinks, purples, reds, and white. Large leaves are deep green and glossy for a lush backdrop to the ornamental blooms.

These deciduous shrubs grow upright with a rounded form, reaching an average of three to six feet tall, depending on the variety. Their size range makes them easy to tuck into various garden spaces, from containers to garden beds. With their profusion of blooms and leafy backdrops, bigleaf types make exceptional mass plantings, hedges, foundation plantings, accents, and specimens. 

These bloomers set buds on old wood, with varieties that rebloom and develop buds on both old and new growth. Old and new wood growers offer an extended bloom season, increased flowering, and showy color from early summer to frost.

Hydrangeas shine among shade-loving perennials like hosta, ferns, tiarella, and astilbe for gorgeous multi-season combinations. They grow beautifully with roses in cooler climates where they tolerate more sun or with roses that tolerate partial shade.

Bigleaf selections are low-maintenance and easy-care, growing best in partial to full shade, depending on climate. Plants are durable with multi-season appeal, and cultivars in unique colors and forms bring grace and elegance to shady garden spots.

Characteristics

The showiest characteristic of this vigorous hydrangea is its bountiful blooms. The large lacy or ball flowers are white or cool blue, violet, magenta, or delicate pink, depending on the soil pH. Acidic soils produce bluer flowers, while alkaline soils yield pinker blooms. You can adjust your soil pH to get either blue or pink blooms by adding sulfur for blue or lime for pink. Soil pH levels don’t impact white-flowering varieties.

Bigleaf hydrangeas feature glossy, deep green, serrated leaves. Small fruit capsules emerge after flowering. The foliage turns bronze burgundy red in fall and adds seasonal interest. Flowers left on the plant persist in dried form into winter.

These woody shrubs are durable in the landscape and have few pests and diseases. With essential cultural growing requirements met, they’re long-lived garden performers.

Hydrangea macrophylla ‘Bailmer,’ sold as ‘Endless Summer The Original,’ changed the landscape by giving the classic bigleaf hydrangea a broader growing range and the capacity to rebloom.

Hydrangeas that bloom on old wood (the previous year’s growth) set their buds for the next season in late summer and early fall. In frigid climates, this exposes young buds to potential winter damage and subsequent loss of flowering in the following seasons. 

Hydrangeas that bloom on new wood (the current year’s growth) develop buds in the spring before blooming. Reblooming macrophyllas set buds on old wood and continue budding on new growth means blooms even if old wood buds don’t withstand winter.

Native Area

Bigleaf hydrangeas are native to Asia. They grow in woodlands along stream banks and rocky areas on the seaside and mountains of Japan, Korea, China, and Southeast Asia.

Planting

Fall and spring are the best time to plant hydrangeas. The mild conditions pose the least stress on new plants as they become established in the garden. For fall additions, don’t add fertilizer at planting time. Plants enter winter dormancy to conserve energy, and fertilizer counters this by encouraging new growth. Wait until spring to fertilize for the growing season.

Dig a hole roughly twice the size of the nursery pot when planting. Gently loosen any tightly packed roots and place the plant in the hole. For the best growth and flowering, shrubs benefit from a level crown rather than being planted too high or too low. Ensure the crown (where the base of the stems meets the roots) is at soil level when tucking plants in. Water new hydrangeas thoroughly at the plant’s base.

Bigleaf hydrangeas make excellent container features given plenty of water, a quality potting mixture, and appropriate light conditions. When planting, choose a container larger than the nursery pot. Add soil so the shrub is at least two inches below the pot’s rim, and infill accordingly.

Transplanting 

If you need to transplant or move a hydrangea to another garden location, it’s best to do so when plants are dormant. Late fall and late winter/early spring are optimal. Dig a wide berth and go deep around established plants to lift as many roots as possible for transplanting. Water deeply after installing the hydrangea in its new spot.

How to Grow

Hydrangeas are carefree, unfussy plants with low maintenance requirements. However, they have specific cultural requirements that promote plant health and vigor, which relate to your garden’s climate and growing zone.

Light

H. macrophylla grows best in partial shade. Morning sun with afternoon shade protection is ideal in most planting areas.

In northern growing areas with cool climates (like zone 6), the bloomers grow best in four to six hours of sun as long as soil moisture is consistent. In hot, southern climates (including but not limited to zones 10 and 11), two to three hours of morning sun or dappled sunlight is sufficient. Plants thrive with more shade – even full shade –  as heat and sun intensity increase.

Direct afternoon sun can burn and scorch leaves and flowers. Provide shade or canopy cover to protect plants from bright rays.

Water

The genus Hydrangea comes from the Greek “hydor,” meaning water, and they require ample water to thrive. Bigleaf varieties are among the thirstiest, with large leaves quickly wicking away moisture through transpiration. Foliage wilts with a lack of moisture. 

About one inch of water per week is sufficient for the reliable bloomers, with more needed during dry spells. Water until frost to prepare hydrangeas for winter dormancy.

Even moisture ensures the plant’s overall health and vigor, but too much water and saturated soils lead to a decline in flowering and fungal issues. To check the soil’s moisture, the best test is to touch the soil and feel one to two inches below the surface. Wet soil means to hold off on watering, and dry signals time to water.

Water hydrangeas in the morning to retain the most moisture before evaporation. Watering deeply, rather than frequently and shallowly, is best for root growth and moisture uptake.

Watering hydrangeas at the plant’s base avoids splashing the leaves and is best for preventing the spread of fungal and bacterial diseases. Drip irrigation, soaker hoses, or direct hand watering accomplish this. If using spray heads or overhead irrigation, water early in the day so plants have a chance to dry out.

For bigleaf growing in pots, ensure the containers are well-draining and check the moisture level regularly. Reduce watering sessions in the winter, watering overwintered containers only when the soil feels dry.

Soil

These summer beauties prefer organically rich, well-draining soils with medium moisture. They grow in acidic, neutral, and alkaline soils, influencing bloom color except for white cultivars, which are unchanged by soil elements.

Blue hydrangea blooms need highly acidic soils with a pH of less than 6.0. Add sulfur or decaying oak leaves to the surrounding soil to increase acidity. Pink blooms occur in more alkaline soils with pH levels above 6.0. To achieve pinker tones, add lime or wood ashes to the soil. A soil test helps determine your soil pH levels and how much you’ll need to adjust them.

Add these amendments in advance of blooming for soil and plant absorption. Fall or late winter is prime for soil amending. A neutral soil yields a purplish-mauve bloom.

For poor soils like clay and sand, generously add composted organic material to the native soil to improve aeration, moisture retention, drainage, and nutrition. Spread a generous three to six-inch layer over the entire planting area.

Temperature and Humidity

Hydrangeas tolerate a range of summer and winter temperatures in zones 6-11, depending on variety. While reblooming varieties tend to be more winter hardy, measures help ensure better flowering and growth for other bigleaf selections in lower zones. Buds on old wood are susceptible to damage in winter extremes, resulting in less flowering in spring.

To prepare hydrangeas for winter, add a three-inch layer of mulch for insulation. Compost, pine bark, straw, and leaf litter work well. Mound leaf litter or straw to 12 inches high around stems to protect the base of plants and buds on old wood. Remove mounded straw or leaves after the final frost passes in late winter or spring.

Plants thrive in regions with heat and humidity, provided there is plenty of air circulation, and moist but not overly wet soil. Bigleaf hydrangeas may wilt in the afternoon heat, even with moist soil, but they’ll revive in cooler evening temperatures.

Provide a sheltered location for overwintering container-grown plantings. For best success, overwinter pots in an unheated garage or basement.

Fertilizing

Macrophyllas benefit from compost amendments at planting and each fall or spring. As heavy bloomers, they’ll appreciate a spring fertilizer application. Look for an organic granular slow-release high in phosphorous, like 10-30-10, to promote growth and flowering.

Avoid overfertilizing, as too much nitrogen produces leafy growth with less flowering. Stop fertilizing in the fall as plants stop actively growing and prepare for winter dormancy.

Maintenance

Bigleaf hydrangeas generally don’t need pruning. If you choose to prune for shaping, do so right after plants finish flowering, cutting no more than one-third of the plant. Prune out dead, weak, or winter-damaged stems in late winter or early spring. Avoid pruning in the fall to retain old wood buds.

Enjoy fresh or dried hydrangeas in floral arrangements by clipping stems back to a pair of healthy buds. Deadhead spent flowers to tidy the plant’s appearance or allow flowers to remain for continued seasonal interest.

As regular maintenance, keep plants mulched with a healthy three-inch layer of pine bark, compost, pine needles, or leaves.

Propagation

These woody shrubs propagate best through stem cuttings and layering. Before creating new plants, ensure a plant patent doesn’t prevent your bigleaf variety from propagation.

Cuttings

Ground Layering

Ground layering is an easy method of propagation that uses existing branching. Choose a low-growing branch and dig a trench beneath it. Scuff a portion of the stem and lay it in the trench, exposing the leafy end of the branch. Cover the stem and weigh it down with a stone or brick. Cut the branch from the mother plant after new roots develop on the stem.

Popular Varieties

Between mopheads, lacecaps, pinks, blues, and whites in various swirling shades and sizes, there’s no shortage of gorgeous H. macrophylla options. Reblooming selections offer a long bloom time that lasts into fall, and some boast autumnal foliage in golds, deep reds, and purple.

‘Big Daddy’

‘Big Daddy’ welcomes the heat of summer with gorgeous mophead blooms in blue or pink depending on soil acidity (blue) and alkalinity (pink). Blooming on old and new wood, plants bear an early season flush of blooms from last year’s stems and continued flowering from buds set on fresh growth. 

This vigorous producer reblooms throughout summer until fall for a long-lasting display. Plants reach five to six feet tall and are hardy in zones 6-9.

‘Blushing Bride’

‘Blushing Bride’ brings pure white double blooms to the ‘Endless Summer’ collection. As they age, the flowers transition to blush pink. The large mopheads are beautiful on the bush and in bouquets.

‘Blushing Bride’ is a reblooming selection with buds on both old and new wood. It’s hardy in zones 5-9 and reaches three to six feet tall and wide. The white blooms of ‘Blushing Bride’ aren’t affected by soil pH levels for coloration.

‘Mariesii Variegata’

This variety features unique foliage with pretty variegation and rich lacecap blooms. Its dark green leaves have brushed creamy white margins to cool the look of the summer display. 

Flat-topped flower clusters have blue or pink centers with light florets and make lovely container specimens to enjoy the flowers and foliage up close. Plants grow four to six feet tall and are hardy in zones 5-9.

‘Endless Summer The Original’

Hydrangea macrophylla ‘Bailmer’ (also called ‘Endless Summer The Original’) is the first hydrangea bred to bloom on both old and new wood, offering extended bloom time, increased flowering, and reblooming from early summer to frost. Plants are more cold-hardy than other bigleaf types, growing in zones 4-9.

The rounded flowers in large clusters are rich, cool blue or delicate pink. The big, glossy leaves turn burgundy red in fall. The versatile size of ‘Endless Summer The Original’, three to four feet tall, makes it a perfect fit for many garden spaces.

Common Problems

Hydrangeas are free of most pests and diseases, though aphids are occasional visitors. Fungal diseases like leaf spot and powdery mildew are sometimes problems. The best prevention is ensuring proper cultural conditions through even watering, partial shade, air circulation, and healthy soils.

Pests

The best way to control insects is through early detection. Aphids are common sap-sucking garden insects that feed on a variety of plants. They don’t often cause a severe threat, but they can cause stress and leave behind a sticky honeydew that can lead to black, sooty mold. 

If you notice curled leaves, stunted growth, or signs of the insect itself, spray plants with a stream of water early in the day to knock them off the stems and deter further damage. A simple horticultural soap or neem oil treats infestations where water isn’t enough.

Diseases

As with pests, the best disease control is prevention through cultural conditions. Common fungal diseases may be an issue with water fluctuations or humid conditions in hot climates.

Cercospora leaf spot is a fungal disease commonly affecting bigleaf, smooth, panicle, and oakleaf hydrangea types. Brown dots on leaf surfaces indicate it, and rainfall and overhead watering promote the spread. Cercospora rarely kills an established hydrangea, though heavily impacted plants may show less blooming and vigor.

To prevent the spread of Cercospora, remove affected leaves and any fallen leaves from the plant during the growing season.

Powdery mildew is another common fungal disease that impacts bigleaf varieties. A gray-white powdery substance appears on leaves, stems, and buds, which may distort and drop.

Remove affected plant parts and any dropped leaves. Horticultural oils like neem can treat fungal diseases early on (but these impact beneficial insects, so be sure to follow application requirements).

Wilts can also affect hydrangeas and there generally is no treatment for these diseases. If you notice large portions of your plant wilting, you may need to remove the entire plant and dispose of it. Prevent wilts by following proper pruning and care practices.

Frequently Asked Questions