How to Plant, Grow, and Care for ‘PeeGee’ Hydrangeas

‘PeeGee’ hydrangeas showcase massive, fluffy white bloom clusters that refresh the garden by bursting into flower in the heat of summer while other bloomers rest. These impressive deciduous shrubs boast prolific flowering to match.

Also named Hydrangea paniculata ‘Grandiflora’, these adaptable flowering shrubs are exceptionally cold hardy. They’re more sun-tolerant than other hydrangea species and thrive in summer heat and humidity. Introduced in the 1860s, ‘PeeGee’ hydrangeas are charming bloomers with an old garden feel and long-standing garden history.

Panicle hydrangeas grow across a wide range of climates and temperatures. ‘PeeGee’ is winter hardy to USDA zone 3, with an upper-temperature range to zone 8 and borderline in 9. Blooms occur on the current year’s growth (new wood), ensuring summer flowering even after harsh winters. Since buds develop on fresh growth, they’re not susceptible to winter freezing like hydrangeas that bloom solely on old wood.

What are ‘PeeGee’ Hydrangeas?

Hydrangea paniculata ‘Grandiflora’, or ‘PeeGee’ hydrangea (also ‘Pee Gee’ or ‘PG’), is a grand-scale deciduous shrub or small tree with a profusion of huge, creamy white panicle blooms in summer and into fall. The large plants are robust growers in a variety of garden conditions, making them among the hardiest and most adaptable of the hydrangea group.

‘PeeGee’ is an old garden favorite with a rich history. The identifier ‘PeeGee’ is likely from shortening the plant’s scientific name to the first initials of paniculata and ‘Grandiflora’. 

Philipp Franz von Siebold named H. paniculata ‘Grandiflora’ in 1829. A botanist and physician, Siebold observed the plant while stationed with the Dutch East India Company on Deshima Island in Nagasaki harbor in Japan. Decades later, he returned to the island to retrieve the plant for European cultivation. Introduced in 1862, ‘Grandiflora’ became a favorite in Victorian gardens.

‘PeeGee’ is a low-maintenance, easy-care hydrangea that grows in full sun to partial shade, preferring afternoon shade in hot climates. These booming bloomers tolerate salty conditions, withstand pollution, and thrive in urban settings.

‘PeeGee’ hydrangea’s durable garden performance, stately form, and grand flowering earned it the Royal Horticultural Society’s Award of Garden Merit. Enjoy their summer glory in a mass planting, mixed border, or as stand-alone specimens. They shine in an open woodland garden location. 

Characteristics

The supreme draw of ‘PeeGee’ is the bundles of tightly packed conical blooms that emerge in late summer to early fall. Usually appearing in July through October, the pyramidal flower panicles begin as pinkish-red buds. They open to lime green fertile flowers (small florets) mixed with infertile star-shaped flowers in creamy white. As the season progresses, the flowers transition to dusky pink. 

The panicle blooms measure six to eight inches long but may grow as long as 18 inches. They last well into fall and eventually turn a buff tan. The flowers attract butterflies, bees, and other beneficial insects.

‘PeeGee’s’ leaves are medium green and ovate with toothed margins. In the fall, the foliage turns tones of yellow and purple-red before dropping. Stems are stout and a rich reddish brown with gray streaking. Flowers left on the plant persist in dried form into winter.

‘PeeGee’ hydrangeas grow large and have the potential to reach 25 feet tall, though they typically grow at lower heights and are amenable to pruning. Their prettiest form is as a multistemmed shrub, whose stems arch under the weight of flowers in full bloom. Growers also train them as small, single-trunked trees.

Panicle hydrangeas contain irritants that may cause skin allergies. They are toxic to dogs, cats, and horses.

Numerous cultivars of panicle hydrangeas feature improved forms, habits, and varying sizes and bloom colors. But for old garden appeal in a statuesque blooming form, ‘PeeGee’ is the classic panicle hydrangea.

Native Area

‘PeeGee’ hydrangeas are native to cool, temperate, and subtropical regions of Asia. They grow wildly in Japan, Korea, China, and Russia’s Sakhalin and Kuril Islands.

Panicle types grow in a range of habitats, from woodlands to thickets and rocky outcrops at varying mountain elevations.

Planting

The optimal time to plant ‘PeeGee’ hydrangeas is in late winter and early spring before new growth emerges. Fall and spring are also suitable for planting, with mild temperatures and adequate moisture for the least stress on new plants as they become established in the garden.

These are large shrubs that benefit from ample air circulation. Spacing plants six to twelve feet apart gives room for mature growth. This hydrangea spacing keeps the shrubs from becoming overcrowded.

When planting, dig a hole large enough to accommodate all roots and loosen the surrounding soil. When tucking plants in, ensure the plant’s crown, where the base of the stems meets the roots, is at the soil level. Hydrangeas grow and flower best when their crown is level with the soil rather than planting high or settling low. Water the new plants thoroughly at ground level.

Transplanting 

‘PeeGee’ hydrangeas have shallow roots and transplant relatively easily. If you need to move a hydrangea to another garden location, it’s best to do so when plants are dormant. Late fall, even after frost, and late winter/early spring are ideal. 

Dig a wide berth 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

‘PeeGee’ hydrangeas are versatile garden shrubs with low-maintenance growing requirements. They are more drought—and sun-tolerant than other hydrangeas and grow in various soil types. For the healthiest ‘PeeGees’, meeting a few vital cultural conditions provides the foundation for the best vigor.

Light

Panicles are adaptable hydrangeas that tolerate sunny conditions, even in warm climates. In northern growing areas with cool climates, ‘PeeGee’ hydrangeas grow best in six hours of full sun with medium soil moisture. In hot, southern climates, morning sun and afternoon shade or dappled sunlight is preferable.

Water

Hydrangeas rely on regular water to thrive (their name, from the Greek “hydor,” literally means water). While ‘PeeGee’ hydrangeas withstand periods of drought better than other selections, they grow and flower best with consistent moisture throughout the growing season and until frost, when they enter winter dormancy.

Generally, one inch of water per week is sufficient for ‘PeeGee’ in moderate conditions. In hot or dry spells, increase watering sessions as needed to maintain consistent soil moisture.

Even moisture ensures ‘Pee Gee’ hydrangeas’ overall health and vigor, but too much or too little water leads to plant stress, pests, and diseases. Signs of overwatering include soft, drooping leaves and wilting flowers. In underwatered panicle hydrangeas, the leaves also wilt, but not usually the flowers. The leading indicators are wet or soggy soils in overwatering and dry soils to a depth of one to two inches in underwatering.

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.

Hydrangeas are best watered at the ground level to avoid splashing leaves and promoting diseases. If you irrigate with spray heads or overhead irrigation, do so in the morning so foliage dries during the day.

Soil

‘PeeGee’ hydrangeas thrive in organically rich, well-draining soils with medium moisture. They also grow in variant soils, from loam to clay to sand. Acidic, neutral, and alkaline soils are fine for ‘PeeGee’, and soil pH doesn’t affect bloom color.

For poor soils like clay and sand, generously add composted organic material to the native soil to improve aeration, moisture retention, drainage, and nutrition.

Temperature and Humidity

Since Hydrangea paniculata ‘PeeGee’ is exceptionally cold tolerant, it doesn’t need much winter protection where hardy. A three-inch layer of mulch year-round helps with insulation and soil temperature regulation. Compost, pine bark, straw, and leaf litter work well. 

‘PeeGee’ delights in heat and humidity, pushing blooms and new growth when other plants conserve energy. Provide plenty of air circulation and medium moist soils.

Fertilizing

‘PeeGee’ hydrangeas grow vigorously with organically rich soils as their base. If you opt to fertilize ‘PeeGee’ hydrangeas, an early spring application is enough. An organic granular slow-release high in phosphorous, like 10-30-10, promotes growth and flowering.

Refrain from overfertilizing panicle hydrangeas, as too much nitrogen produces quick, weak growth with less flowering. Stop fertilizing in the fall as plants stop actively growing and prepare for winter dormancy.

For fall-planted hydrangea additions, hold off on fertilizing at planting time. Hydrangeas enter winter dormancy to conserve energy, and fertilizer counters this by encouraging new growth. Wait until spring to fertilize for the growing season. 

Maintenance

‘PeeGee’ hydrangeas are unfussy, easy growers in the landscape. Prune the robust shrubs for shaping or size in fall or late winter/early spring before new growth begins. Since ‘PeeGee’ blooms on new spring growth, pruning old stems won’t impact budding and flowering. To direct energy into producing huge flowers, some gardeners select five to ten primary shoots to become central stems, pruning out others.

Prune out dead, weak, or winter-damaged stems in late winter or early spring. For best health and form, ‘PeeGee’ benefits from cutting back one-third of its total size each year. A six- to eight-foot ‘PeeGee’ is in prime form.

‘PeeGee’ hydrangea blooms make gorgeous cut flowers for fresh floral arrangements and dry beautifully. The flowers on the plant add continued seasonal interest into fall and winter.

Propagation

‘PeeGee’ hydrangeas propagate most easily through softwood stem cuttings. Take cuttings from new growth, ideally from leafy stems without flowers. 

Cuttings

Here are simple steps for best practices in taking cuttings:

• Cut a four-to-six-inch piece of healthy stem from new growth.
• Remove the foliage from the bottom section of the cutting, keeping one to two upper leaves intact. If the leaves are large, cut half of them off. Keep the cuttings moist until ready to pot.
• Optional: moisten the cutting and generously coat the lower stem with rooting hormone. Tap off any excess rooting powder.
• Plant the cutting in at least two inches of moist, well-draining potting mix.½ to ⅔ of the stem should be covered, including at least two leaf nodes.
• Place the pot or tray in a bright, warm location, avoiding direct sunlight.
• Mist or water as needed, keeping the soil evenly moist.
• When the cutting resists a gentle tug – generally two to four weeks for hydrangeas – roots are in place, and cuttings are ready to be repotted.
• Plant the cuttings in four-inch pots and move them outside in mild conditions. New plants will be tender.

Common Problems

‘PeeGee’ hydrangeas occasionally experience aphids and spider mites, and fungal diseases like leaf spot, powdery mildew, and rust can also be problems. The best prevention for pests and diseases is ensuring proper cultural conditions through even watering, air circulation, and healthy soils.

Pests

The best way to control insects on ‘PeeGee’ hydrangeas is through early detection. While this variety doesn’t carry significant pest problems, aphids and mites may appear.

Aphids are common sap-sucking garden insects that feed on a variety of plants. They don’t often pose a severe threat, but they can stress plants and leave behind sticky honeydew that can lead to black, sooty mold. 

Spider mites live on the undersides of leaves, indicated by webbing and light yellowing of leaf surfaces. Beneficial predatory insects like ladybugs and predatory mites help control populations.

If you detect insect infestation, spray the plant with a strong stream of water early in the day to deter and knock insects off the stems. A simple horticultural soap or oil can rid the plant of insects, but follow label directions, as these also affect beneficial insects. 

Diseases

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

Cercospora leaf spot commonly affects bigleaf, smooth, panicle, and oakleaf hydrangea types. Rainfall and overhead watering promote the spread of this fungal disease, visible by brown dots on leaf surfaces. Cercospora rarely kills an established hydrangea, though heavily impacted plants may show less blooming and vigor.

To prevent the spread of Cercospora, remove fallen leaves from around plants and remove affected leaves from the plant during the growing season. If the disease is allowed to progress, bud blight and bacterial wilt can take hold. These can lead to the death of the shrub. Therefore, prevention is key.

Powdery mildew is another fungal disease that can potentially impact panicle hydrangeas. It appears as a gray-white powdery substance on leaves, stems, and buds. Leaves may distort and drop. As with Cercospora, remove affected plant parts and any fallen leaves.

Rust, another common fungal disease, is possible in hot, humid summer climates. Powdery spores may appear on the undersides of yellowing leaves. If rust is spotted, cut off the infected leaves. Rust spreads readily, so make sure to destroy the infected plant parts.

Horticultural oils like Neem can treat fungal diseases early on and prevent their spread to healthy parts of the plant. Removing affected leaves and branches is the best option for any severely impacted garden plants in decline.

Frequently Asked Questions