Usually, this is a moisture issue. Sometimes, the plant can be root-bound, too. Gently dig the plants early in the morning to check for both conditions. If needed, lightly loosen the roots with your hand. You can also soak the root ball in water until it’s moistened through. Make sure you maintain uniform moisture for your hydrangeas.
Location can also be an issue. If they’re getting sun burnt, they’d do better with light shade.
Usually, this is a moisture issue. Sometimes, the plant can be root-bound, too. Gently dig the plants early in the morning to check for both conditions. If needed, lightly loosen the roots with your hand. You can also soak the root ball in water until it’s moistened through. Make sure you maintain uniform moisture for your hydrangeas.
Location can also be an issue. If they’re getting sun burnt, they’d do better with light shade.