Selection

• Hydrangeas are primarily grown for the abundant long-lasting flower heads on the plant. The flower buds are developed on the new growth of the prior year, so it is essential to protect the new growth over the winter from wind and cold. Selecting an appropriate hydrangea species and variety that will thrive in your regional growing environment will also help your hydrangea survive the winds and cold of winter.
  
  

USDA Zones 4 to 8

• In many areas of USDA hardiness zones 4 to 8, your hydrangea will be protected from harsh winter winds by a deep insulating layer of snow. But most hydrangeas growing in the colder regions will need some type of protective covering to avoid direct wind contact. Cold winter winds not only can break off the new growth branches of your hydrangea, but also increase the potential of freezing or damaging the flower buds that are on the new growth. Smaller hydrangea plants can be protected from winter winds by being covered with a buildup of dry leaves and mulch in the late fall. Larger hydrangea plants will need a wire cage placed around the bush, then filled with leaves, lightweight mulch or pine needles to cover the plant. In the spring, after the threat of frost has passed, carefully remove the natural insulation.
  
  

USDA Zones 9 to 10

• In the milder USDA hardiness zones 9 and 10, the threat of frost or freeze is not present but this does not mean winter winds will not damage your hydrangea. The winter winds in warmer regions have a tendency to dry out a plant or break new growth branches. Even though your hydrangea has gone into a dormant stage over the winter, like hydrangeas growing in Northern regions, the new growth on the plant contains the flower buds for the upcoming summer. If the ends of the new growth become broken or damaged from the drying winter winds, the buds will die. Protect your hydrangea over the winter from wind by placing a wire cage around the plant, then cover the outside of the cage with burlap cloth. The burlap acts as a wind block while still allowing for air circulation.
  
  

Tips

• By covering your hydrangea you are protecting the new growth and flower buds from winter winters, but at the same time you do not want to unintentionally cause damage in doing so. If you are surrounding your plant with leaves or mulch, be careful not to break any branches. Periodically check your leaf-covered hydrangea over the winter to make sure the leaves have not settled downward and exposed your hydrangea. Oak leaves are recommended for coverage because they do not compact or settle as readily as other types of leaves. Never use plastic to protect your hydrangea from winter wind in any zone.