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
Hydrangeas droop for many reasons, but it's rarely due to illness. When hydrangeas are drooping, they're often expressing their dislike of local conditions. Too much sun and not enough water lead to wilt; heavy flower loads can cause tender branches to bend until they touch the ground.
But hydrangeas are among the few plants that can draw moisture in through their florets, so it's possible to perk up wilted blooms by completely submerging them in water and letting them sit for a few hours to rehydrate.
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.
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.
Too much sun exposure can cause your hydrangea shrubs to burn on its leaves and blooms. Also, be sure to put your fingers in the soil to see if it needs watering. We do recommend a soak versus light watering each day, but you should be sure that the soil is always moist – not wet – by sticking your fingers in the dirt.
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.
It's when they consume most of their water, so they are most prone to wilting at night when they're not getting the water they're used to. You'll need to help your hydrangea blooms get the excess water that they need in a different way because they usually can't consume enough water from their stems alone.
It is suggested that Hydrangea wilt so soon after being cut because their stems contain a sticky substance that clogs the stems preventing moisture reaching the top of the stem to the head.
Wilting or mushy leaves: overwatered hydrangea leaves are heavy and drooping. They may be mushy or pulpy to the touch because their cells are flooded. Underwatered plants, on the other hand, will have dry and crispy leaves.
Remove the wilted hydrangeas from your arrangement and re-cut the stems on a 45-degree angle. Make a vertical slit in the incision and hold the stem upright in the boiling water for about 60 seconds. Place the hydrangeas back in your floral arrangement and they should revive themselves in an hour or so.
In addition to changing color, an overwatered hydrangea's leaves may wilt. In extreme cases, the leaves will begin to drop off the plant.
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.
A wilted plant can recover in a few weeks with the right care and attention to address the root cause of wilting. It is worth noting, however, that not every wilted plant has the stored energy to make a full recovery, and some plants can take months to look as they did originally.
If the leaves are drooping, it is time to water the plant. If the leaves are yellowing and turning brown, check for standing water or a clogged drainage hole.
Doggett says the wilting isn't cause for alarm as long as they are able to rehydrate overnight and appear completely refreshed by the morning. "If the hydrangea still looks wilted the next morning, you need to increase your watering," he advises.
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.
Brown, tan, yellowish or black spots on hydrangea leaves may be anthracnose. You can also identify it by cankers that form on stems and branches. Anthracnose can be fatal to hydrangeas, so prune out dead or diseased plant parts and destroy them.
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.
The reason for hydrangeas wilting and dying is because there is not enough moisture around the roots due to lack of watering or rainfall, the soil drains too quickly, too much sun or excessive wind saps moisture from the leaves. Hydrangea flowers can droop due to excess fertilizer.
Hydrangeas should be planted in moist, rich soil. In soil that drains quickly, such as sandy soil, wilting occurs much faster than in soil rich in organic matter with better water-holding ability. Shallow watering can also cause wilt.