The hydrangea is a simple plant that can have a big impact on any garden. To keep this beauty growing healthily year after year, you should take care of your hydrangeas not only during the growing season, but also during the winter. The winter care of hydrangeas isn't difficult, and when done correctly, can protect your plant and ensure you see many large, colorful blooms the following year.
Wait until after the first frost in late fall or early winter as your signal that it is time to prepare your hydrangea. If you work too soon, you risk insulating the plant with too much heat in the soil and it won't successfully go dormant.
Use gloved hands and/or a garden rake to pull debris material away from the base of your hydrangea, such as sticks or any spent blooms that have dropped. Work carefully so you don't break off any branches at the base of the plant.
Spread a three- to four-inch deep layer of mulch around the hydrangea's base to insulate the plant. This insulating mulch layer can be made up of pine needles, oak leaves, straw or compost, as long as it is a light material that won't pack down.
Plant garden stakes in a circle around your hydrangea, using a rubber mallet to secure them; it is okay to use more than six if necessary. Be sure the stakes aren't right up against the branches of the hydrangea, but around the circular shape of the bush, and are as tall as the hydrangea.
Wrap a large piece of burlap around the stakes and secure it by using a staple gun or tying it to the stakes with string. The burlap should extend all the way to the ground and be as tall as your hydrangea.
Carefully take the enclosure down in the early to mid spring without damaging the hydrangea. Usually, you can use the sight of forsythia blooming as your signal that it is time to remove the covering.