9 Tips to Keep Your Hydrangeas Happy During a Drought

Hydrangeas are resilient performers across climate zones, but the moisture-loving shrubs exhibit stress in prolonged hot, dry spells.

The genus Hydrangea comes from the Greek “hydor,” meaning water, reflective of their ample water needs. Drought can spell trouble for the big bloomers, and extra care goes a long way toward overall health and vigor.

Starting with optimal cultural conditions for your type of hydrangea provides the best foundation for resiliency against seasonal fluctuations. When it comes to drought and hydrangeas, the best we can aim for is to protect the woody ornamentals as summer gets tough. With a few of these tips, hydrangeas can recover and return to full-flowering glory.

Watch for Signs of Stress

Hydrangeas wilt in response to high heat, sunny, and dry conditions. While they usually perk up with cooler evening temperatures, they may not in prolonged drought. If your hydrangea shows excessive wilting without rebounding, it might be due to sun or heat exposure during dry conditions.

Sunscald and Leaf Scorch

Sunburn and leaf scorch are heat-related issues that can affect drought-stressed hydrangeas in the summer. Sunburn happens with exposure to intense UV rays, resulting in sunscald. With sunscald, bleached, whitish patches appear on the leaf surface.

The blisters become dry and papery as the tissues in the affected area die. Minor cases occur at lower temperatures and present as yellowish or brownish, crispy spots on the leaves. Edges and between veins are likely to show damage on foliage.

Leaf scorch is another heat-related symptom that occurs at high temperatures with a lack of moisture. Leaf scorch can happen in bright sunlight but also in shadier zones. It’s related to hot, drying winds and a lack of moisture. Even hydrangeas in the shade may experience leaf scorch due to dry heat.

As they draw water from the roots for interior cooling, the broad leaves lose moisture to the atmosphere faster than they can uptake it. Leaf and petal edges become brown and crisp.

The good news is that the woody shrubs can recover from heat stress. It may be the following year that they show full, leafy, flowering recovery.

The Best Location

Most hydrangeas grow best in partial shade. Panicle hydrangeas (H. paniculata) are adaptable exceptions that handle more sun. For most, morning sun exposure and afternoon shade protection are ideal.

In northern growing areas with mild summers, the shrubs grow best in four to six hours of sun, as long as soil moisture is consistent. For gardens with hot summers, place hydrangeas on the shadier side of their preferred light requirements. In hot, southern climates, a few hours of morning sun or dappled sunlight works well.

They thrive with more shade protection in the intense afternoon rays to defend against sunburn and scorch. 

Water Deeply and More Often

The key to protecting hydrangeas during drought is providing supplemental water. Water deeply and more often than their normal seasonal protocol. Aim for even soil moisture, letting irrigation run to reach the deep roots and surrounding soils.

Extra water during summer extremes creates turgid, water-filled stems and leaves. It also serves to cool the roots and lower internal temperatures.

In normal conditions, about one inch of water per week is sufficient for hydrangeas. More is beneficial during dry spells to account for evaporation and daily water loss. Ensure soils have good drainage to avoid soggy conditions, as too much water and saturated soils lead to wilt and other fungal diseases. Touch and probe the soil several inches deep to gauge moisture during the heat wave.

Water hydrangeas in the morning, when possible, to retain the most moisture before evaporation. Directing water to the base of the plant avoids splashing the leaves and is best for preventing the spread of fungal and bacterial diseases. It also delivers water volume straight to the roots. Drip irrigation and soaker hoses offer concentrated, low-volume delivery to penetrate the root layer.

For potted specimens, ensure the containers are well-draining and check the moisture level often during periods of dry heat. Hydrangeas in containers dry out more quickly than in-ground specimens, which benefit from the surrounding soil mass.

Refresh Mulch

Rely on a layer of mulch to retain soil moisture and to regulate soil temperatures for hydrangeas during drought. In summer, mulch helps keep the roots cool and moist. In the winter, it protects against fluctuating extremes and frost heaving.

Add a two-to-three-inch layer for the best protection. Leaf mulch, leaf mold, weed-free straw, compost, bark, and aged wood chips are good options. They’ll also add nutrition as they decompose.

Provide Shade Protection

Hydrangeas are top contenders for protective shade cover during temperature and moisture extremes. Shade coverage is one of the easiest ways to protect them from and defend against sunburn during exposed times of day.

Shade protection is multipurpose, shielding leaves and blooms from the sun while cooling the roots. It also reduces water loss and lowers internal temperatures.

Shade cloth is one of the easiest ways to screen hydrangeas during drought. The lightweight fabric screens UV rays while allowing natural light, moisture, and air flow. Thin bedsheets serve as a convenient shade cloth.

A strategically placed trellis or arbor offers shade protection. An umbrella or pop-up canopy offers temporary shade during the hottest, driest spells. Burlap or a window screen on stakes also creates a filter.

Avoid Overfertilizing

Too much fertilizer during the growing season creates an excess of nitrogen. This promotes quick, weak growth susceptible to sunburn and leaf drop, as well as pests and diseases. It also reduces flowering. Fertilizing in hot weather, too, causes stress. Skip applications during environmental extremes to protect hydrangeas during drought.

With the right nutrition, we can maintain vigorous leafy growth to protect underlying new, tender growth and buds. Amend with compost in the spring to add low-grade nutrition and to improve aeration.

A balanced fertilizer for acid-loving plants gives hydrangeas a boost in spring. Make sure it contains phosphorus, rather than a higher nitrogen rate, to promote blooming.

Limit Pruning

Avoid pruning and trimming during dry spells to keep upper leaves in place for shielding lower growth. We also don’t want to spur new growth via cutback during environmental stressors, which are susceptible to heat stress and sunburn.

Tidy up by removing crispy blooms, but if your hydrangea has sunburned leaves, resist the urge to remove them right away. If they have any green (chlorophyll) left, they continue to photosynthesize to support the plant. The already-exposed leaves also continue to shade others from direct sun.

Remove them if they begin to show additional signs of stress, like disease markers. Pathogens may enter the foliage through the injured patches.

Hydrangeas don’t require regular pruning, but if you choose to prune for shape or to manage size, do so immediately after flowering in late summer/early fall for old wood bloomers and in late winter/early spring for new wood selections. Remove up to one-third of the shrubs, but only when conditions are moderate.

Scout for Pests and Diseases

With drought and heat stress comes the opportunity for pests and diseases to crop up. Water consistently, especially at the base of the plant, to avoid drastic moisture fluctuations.

Keep an eye out for spider mites, which flock to drought-stressed plants in dry conditions. The sap-feeding insects colonize around leaf veins and mid-ribs underneath leaves. Females lay eggs, and the larvae quickly feed on sap and tissues. Adults feed and produce tight webs around leaves, stems, and branches.

With spider mites, foliage shows light yellowing, pale spots, and stippling on leaf surfaces that may become bronze. Leaves may stiffen and curl before prematurely dropping.

If you detect spider mites or other piercing pests, spray the plant with a strong stream of water early in the day to displace the insects from leaves and stems. A simple horticultural soap or oil limits the pest population, but follow label directions, as these treatments also affect beneficial insects.

Fungal Problems

Hydrangeas are prone to common fungal problems to scout for during heat and drought damage.

Cercospora leaf spot commonly affects bigleaf, smooth, panicle, and oakleaf hydrangeas. Brown dots appear on the leaf surfaces and spread through splashing rainfall and overhead watering. The fungus 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.

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

Rust occurs most often in hot, humid situations. Powdery spores appear on the undersides of yellowing leaves. With rust, cut off the infected leaves and discard debris to limit its easy spread.

Horticultural oils like neem can treat fungal diseases early on. Removal is the best option for any severely impacted shrubs in decline.

Choose Resilient Varieties

We love the irresistible bigleaf hydrangea (H. macrophylla) with its massive mophead blooms, but they require more moisture and shade protection than others. Bigleaf varieties are among the thirstiest, with large leaves that quickly wick away moisture through transpiration. If you’re noticing a trend of heat and drought stress, planting more resilient selections in the future may reduce issues.

By choosing species native to North America and suited to our growing regions, we increase durability and landscape performance. While resilient and tolerant of varying soil types, these hydrangeas still don’t withstand prolonged drought without supplemental irrigation.

Oakleaf Hydrangea

Hydrangea quercifolia is native to the southeastern U.S. The upright shrubs have creamy white pyramidal blooms, deeply lobed leaves, and exfoliating bark. They also show red fall color.

Cultivars like ‘Snow Queen’ and ‘PeeWee’ feature improved forms and color variations. Hardy in zones 5-9, oakleaf needs winter protection in zone 5. These bloom on old wood.

Smooth Hydrangea

Hydrangea arborescens, also called wild hydrangea, is native to the U.S. and grows across varying climates in zones 3-9. The species flowers in white or lime green with newer cultivars in pink, rose, mauve, and cerise.

Smooth hydrangea flowers appear in domed or flat-topped clusters from early summer through fall. Cold-hardy and sun-tolerant, they set buds on new wood, making them reliable even after cold winters.

Panicle Hydrangea

Hydrangea paniculata, or peegee hydrangea, bears dense, pyramidal blooms tightly packed with individual flowers. Colors range from creamy white to lime green to pink, tinged with red. Panicle hydrangeas bloom on new wood and are cold-hardy. They grow best in zones 3-8 (borderline in 9) and tolerate more sun than other varieties, even in warm climates.

They adapt to varying soils and occasional dry spells. The large flower heads get weighty on the stem, but newer cultivars feature improved stem strength. The species’ height varies from 2 to 20 feet, depending on the variety.

Assess Transplant Needs for Fall

If your garden conditions have opened up since originally planting the hydrangea, or if it seems constantly stressed by sun exposure, moving it to a shadier locale may be beneficial for the long term to limit drought stress in hydrangeas. Given a few best practices for success, the woodies respond well to transplanting.