Shade cloth is available at many garden centers and home improvement retailers. It comes in different densities so get the one that provides the most shade. This is a temporary covering. You set out wooden stakes around the plant(s) and then drape the shade cloth over the plant(s) using the stakes for support.
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.
Drooping Leaves
The most likely cause of this is a lack of water. You will typically see these leaves drooping in the afternoon, especially if your plants are receiving too much afternoon sun. Hydrangeas are at their best planted in partial shade with four to six hours of morning sunlight.
TOO MUCH SUN
Conversely, too much direct sun may stress hydrangea plants, which can force them to conserve energy by not forming flowers.
Deeply water 3 times a week to encourage root growth. Bigleaf and smooth hydrangeas require more water, but all varieties benefit from consistent moisture. Use a soaker hose to water deeply and keep moisture off the flowers and leaves. Watering in the morning will help prevent hydrangeas from wilting during hot days.
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.
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.
The Endless Summer hydrangea thrives in partial shade and needs well-drained soil with consistent moisture. It does need some sunlight for photosynthesis and flowering potential, but overly hot direct sunlight can scorch the leaves.
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.
A 2-3” layer of mulch around the base will help keep the moisture in as well but remember, no “volcano” mulching (where you pile the mulch higher up next stem). Mulching around your hydrangea will encourage deep roots to develop, adding to winter hardiness. Right now, your hydrangeas should be leafed out.
Bigleaf is divided into two flower types – lacecap and mophead. Both are among the most heat-tolerant hydrangeas, although mophead prefers a bit more shade. Panicle hydrangea (H. paniculata) – Panicle hydrangea is one of the most sun tolerant 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.
You can use vinegar to lower the pH of your soil, but be aware that in order to achieve blue blooms, you will need both an acidic environment and aluminum ions. The acidic environment will also need to be a sustained over a period of time, which could be hard if rainwater is washing the vinegar away.
To give hydrangeas their best chance at success, apply a layer of chunky mulch around the base of the plant. Decorative mulch is helpful but we recommend straw, marsh hay, or fallen leaves.
"Hydrangeas can look stressed in extreme heat but will perk up when temperatures drop," says Clay. "If the plant is looking a bit sad even with cooler temperatures, it likely needs water."
Water your hydrangeas in the morning before the heat of the sun is strong enough to quickly evaporate soil moisture. Try to avoid watering at night, which can encourage mold and mildew as the moisture sits through the cool night. Water your hydrangeas through the growing season as well as in late fall.
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.
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).
For hydrangeas planted in ground.
For optimal growth, bloom production, and quality, fertilize three times: In early spring when plants are just leafing out. In early May to boost their flower production for summer. In late June/early July to help your plants finish the summer strong.
Potted hydrangeas overwinter best in a garage or basement where the temperature stays cool but doesn't freeze. The plants will go dormant, but you'll still need to water the pots occasionally, about once a month, to keep the roots moist, until spring.
Hydrangeas grow best if they are fertilized once or twice in the summer.