In regions where the temperature regularly falls below 5 degrees Fahrenheit, create a fence around the hydrangeas to protect them throughout the winter. Complete winterization prior to the predicted date of the first frost. In warmer climates, hydrangeas do not require special winter preparation.
Stake a circle around the hydrangea plant and create a fence with a porous material, such as chicken wire or burlap. Fill in the space within the fence with such non-compact material as dead leaves, pine needles or straw. Ensure coverage of even the furthest tips of the branches, which is where buds form. Check that the plant remains completely covered throughout the winter, adding any additional insulating material when necessary. Some gardeners choose to cover the entire plant in a breathable cloth or upturned trash can to retain more heat. Avoid plastic sheeting, which can trap in moisture and restrict airflow. Do not remove protections until all danger of frost has passed. Not all types of hydrangeas require preparation for winter. Only plants in the hydrangea macrophylla species require winterizing. This species includes bigleaf hydrangeas, mophead hydrangeas and hortensias. Paniculata and Annabelle hydrangeas are native to the midwest and can survive winter on their own.