How To Care For Established Hydrangeas. Cover it with a plastic bag and mist it often to keep it moist. Deeply water 3 times a week to encourage root growth.
Arrange the stems in a vase and place in a cool spot. Place the freshly cut hydrangea stems immediately into cold water to avoid wilting. Protect your hydrangeas from cold winds by planting them in a sheltered spot or with a burlap windscreen or burlap frame filled with dry leaves.
Provide plenty of water Hydrangeas should get a deep watering about three times a week.
The best time to plant Hydrangeas is in fall or early spring. Keep Hydrangeas well watered until they are established. Adding aluminum sulfate helps lower pH and adds aluminum but be careful using it. And if your flowers are looking sad Bladow suggests soaking the entire hydrangea in cool water for about 45 minutes.