Although hydrangeas are relatively hardy plants, some hydrangeas are more sensitive to cold than others and may not bloom if their flower buds are damaged by extreme cold and harsh winter winds.

However, by adding a little winter protection and providing hydrangeas with winter care
that they need, you can avoid losing flower buds and maximize flowering. Whether you’re growing hydrangeas in pots or in your garden, these seven tips will teach you how to protect hydrangeas from frost and cold and ensure your plants bloom well next season.

Choose the right hydrangeas

Although hydrangeas can be overwintered with mulch and other winter protection products, you can avoid many problems by purchasing hardy hydrangea varieties from the start.

“It is especially important to check the zone of the hydrangea you are buying and make sure it is
suitable for your location,” says Scott Bolotin of Morning Star Perennials & Nursery.

Bolotin explains that new woody hydrangeas, such as panicles and smooth hydrangeas, are especially winter hardy and are the best choice for cold climates. Old wood hydrangeas, on the other hand, are more susceptible to cold damage and are more likely to need winter protection in cool areas.

In addition to varieties of hydrangea, Bolotin explains how it is useful to buy plants that have previously overwintered in the area.

“This will let you know that this type of hydrangea can be successful in your area,” says Bolotin.

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Choose a protected place for cultivation

Hydrangea flower buds are more likely to suffer damage if the plants are in an area exposed to the elements. To avoid this, plant cold-sensitive hydrangeas, such as large-leaf hydrangeas, in sheltered areas that are protected from strong winds.

Trees, retaining walls and DIY windbreaks can be used to protect hydrangeas as long as these structures do not block too much sun.

Apply mulch

Adding a two- to three-inch layer of natural mulch around the base of hydrangea plants at the end of the season will help insulate the soil and prevent the soil from drying out too quickly.

In addition, mulch also prevents frost, which can disrupt hydrangea roots and make them more susceptible to cold damage. If you want to give your hydrangeas an extra boost, sprinkle some compost or aged manure before mulching.

Stop pruning and fertilizing

Pruning hydrangeas at the wrong time of year can remove flower buds and reduce blooms, while fertilizing hydrangeas late in the season can cause the plants to droop and expose them to the cold.

The solution? Prune old wood hydrangeas only right after they finish blooming, prune new wood hydrangeas from late winter to early spring, and stop fertilizing all types of hydrangeas in early fall!

Water Well

Well-watered plants are more resistant to cold damage than water-stressed plants, so it’s essential to water hydrangeas until the ground is frozen solid. If you live in an area where it snows in the winter, the snow will eventually insulate the soil and provide moisture to your plant’s roots.

However, if you live in an area where the ground does not freeze in the winter, continue to deeply water your hydrangeas about once a month if rainfall is scarce.

Add insulation

New wood hydrangeas and old wood hydrangeas in growing zones 7 and higher will generally not need winter protection. But old wood hydrangeas growing in areas where they are marginally hardy can benefit from additional insulation.

One popular option is to install wooden stakes and burlap wrap around vulnerable hydrangeas. But you can also add a wire cage over your plants and fill it with insulating straw or autumn leaves. To avoid snow stressing your plants, leave the top of the hydrangea cover open and remove the covers in the spring when temperatures rise above freezing.

Protect potted plants

Potted hydrangeas need more winter protection than garden plants and should be moved to a sheltered spot before the ground freezes in winter. A garage or cold basement is ideal for storing potted hydrangeas as long as these locations remain above freezing.

Once your hydrangea is safely stored indoors, wrap a blanket or foil around the pot, apply mulch, and water the plant lightly about once a month until you can return it to your garden in the spring.