4. All hydrangeas will turn brown if they wilt too many times in hot weather. Water these shrubs deeply every few days in the heat of the summer (note that hand watering isn't deep enough) and mulch around plants to hold moisture in the soil longer.
Provide Some Shade
Most varieties of hydrangea prefer shade during the heat of the day. Most varieties of hydrangea prefer afternoon shade. If you think your hydrangea can benefit from a break from the sun you can purchase shade cloth online or from your local garden center.
If your hydrangea foliage is also damaged, it may be sunburned (crispy or brown around edges). Depending on the amount of total damage, your plant will eventually recover from severe sunburn, but may not rebound from extreme drought.
In warmer areas, many hydrangea types will suffer in the afternoon's scorching sun. The leaves and flower heads may burn, turning brown. If you notice this, that means your hydrangea is getting too much sun. Try moving it into filtered shade, or an area where it gets only a few hours of morning sun.
Burnt leaves and fronds in the garden look awful and are a constant reminder of the hot weather we've been experiencing. Ugly as it is, the best thing to do about burnt growth is to leave it be and to provide as much water as possible to damaged plants.
For example, hostas that are sufficiently shaded may still have leaf scorch symptoms if weather is incredibly hot and dry (Figure 2). Once leaf tissue is scorched, the damaged areas will not recover; however, minor damage, while unsightly, will not kill the plant.
Hydrangea Heat Stress
Heat and drought stress can cause the stomata of your hydrangea plant to remain open as they try to absorb water vapor from the environment that they are in. Unfortunately, this causes water to be lost more than it is gained which over time translates into wilting.
Bigleaf hydrangeas, also known as hydrangea macrophylla, vary especially with some of the newer cultivars being bred to better tolerate heat and sun, but most of these including the mopheads and lacecaps prefer some shade, especially during the afternoon.
All hydrangeas will turn brown if they wilt too many times in hot weather. Water these shrubs deeply every few days in the heat of the summer (note that hand watering isn't deep enough) and mulch around plants to hold moisture in the soil longer.
Leaf scorch results when the leaves lose water faster than it can be supplied by the roots, so wilting may occur before scorch is noticed. Common causes include inadequate watering, exposure to strong light (sunlight or reflected light), high temperatures, or dry, windy conditions.
To revive hydrangeas with brown leaves and flowers it is necessary to recreate the conditions of the hydrangea's native environment by planting hydrangeas in moisture retains soil, watering the hydrangea as often as required to keep the soil moist and sheltering the hydrangea from wind which saps moisture.
Hydrangeas need more water than most garden plants and will begin to wilt quickly without it. To ensure that Hydrangeas thrive, water deeply two to three times a week in the summer. Be sure to water in the morning or evening so that water does not evaporate as quickly as it would during the heat of the day.
Mulching is always a fantastic idea (a must, if you ask me!) and especially important to protect plants in heat waves. Mulch is a layer of material that goes on top of exposed soil, which helps to buffer against temperature extremes and promotes more steady soil temperatures overall.
Most hydrangeas prefer only morning sun. Yet one type of hydrangea can soak up the sun all day: the panicle hydrangea. While they can stand the sun, these do just fine in partial shade, too. Plus, panicle hydrangeas are the hardiest hydrangeas.
Some gardeners report success in turning their hydrangeas blue by applying coffee grounds to the soil. The coffee grounds make the soil more acidic, allowing the hydrangea to more easily absorb aluminum. In addition, fruit peels, lawn clippings, peat moss and pine needles, are thought to have a similar effect.
Here's what to look for: Leaf discoloration: hydrangea laves typically become yellow and brown when overwatered. However, the discoloration can also be a sign of underwatering. Usually, when the plant is overwatered, the browning occurs on the edges of the leaves.
Hydrangea Care Tips
Water at a rate of 1 inch per week throughout the growing season. Deeply water 3 times a week to encourage root growth. Bigleaf and smooth hydrangeas require more water, but all varieties benefit from consistent moisture.
It's best to start adding coffee grounds to the soil months before the blooming season begins, ideally in the late fall. You can repeat the process with your typical fertilizing schedule.
Hydrangea Light Requirements
Hydrangeas also prefer morning light, which is typically gentler and less hot than afternoon light. While some hydrangeas will tolerate full sun (six hours or more of direct light), they'll likley perform better with a bit of shade.
Panicle hydrangeas can handle hot sun
While they are drought tolerant and stand up to heat, I still like to provide shade during the hottest part of the day. And just because they are drought tolerant doesn't mean you should let them wilt. As with all hydrangeas, plants will thrive with regular irrigation.
While several species of hydrangeas thrive in shade, panicle hydrangeas (Hydrangea paniculata) are the best for growing in full sun. These summer-blooming shrubs produce large clusters of white flowers for several weeks. The showy blooms fade to shades of pink or red before drying to beige.
Stephen Sullivan, the editor at Plant Native, says: 'Among the different types of hydrangeas, the Oakleaf hydrangea (Hydrangea quercifolia) and the Panicle hydrangea (Hydrangea paniculata) tend to be more resilient in dry conditions compared to the Bigleaf hydrangea (Hydrangea macrophylla).