How to Winterize Potted Hydrangeas in 7 Steps

When winter arrives, container-grown plants need a bit of extra protection from the cold. In this article, gardener Briana Yablonski will share how to care for potted hydrangeas so they survive the winter.

Written by Briana Yablonski Horticulture review by Sarah Jay Last updated: October 12, 2024 | 5 min read

A vibrant arrangement featuring clusters of large, round flowers in shades of pink and blue, surrounded by lush green foliage. The scene is set in a bright garden, with a rustic, dark green plant container, twine, and a small silver watering can nearby, enhancing the natural aesthetic.

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When you think of hydrangeas, you may imagine large shrubs that brighten up the front of a house or small bushes that beautify walkways. But not all hydrangeas grow in the ground. Dwarf varieties of these flowering shrubs can happily grow in containers on porches, patios, and decks.

Although some hydrangeas will grow well in pots, these container-grown perennials will be more susceptible to cold winter temperatures than their in-ground cousins. That’s because soil doesn’t protect them from the cold air. Therefore, you’ll need to treat your potted hydrangeas with extra care if you want them to survive the winter.

Fortunately, winterizing potted hydrangeas is simple. I’ll share a few simple steps you can take to help them make it through the winter.

Determine Your Hydrangea Variety

An exuberant collection of flowers in varying shades of blue and pink, creating a rich visual tapestry. The leaves are broad, deep green, and glossy, contrasting beautifully with the blooms. The backdrop consists of soft sunlight filtering through a window, adding a serene ambiance. — If your potted hydrangea can survive the winter outdoors without any extra help, leave it alone!

Before you begin hauling around heavy pots and breaking out sheets of burlap, determine whether you need to take extra steps to prepare your plants for the winter. If your potted hydrangea can survive the winter outdoors without any extra help, leave it alone!

Two main factors determine whether or not you should provide extra support to your hydrangea over the winter: the variety and your hardiness zone.

With close to 100 species of hydrangeas and hundreds of more cultivars, you have no shortage of options when choosing one of these flowering shrubs. Since each variety has varied cold tolerance, pay attention to which variety you’re growing.

Many panicle hydrangeas and smooth hydrangeas can survive winters outside in zone 3, but big leaf and oak leaf varieties typically need winter protection when grown in zone 5 and below.

Know Your Hardiness Zone

A small indoor plant showcasing fresh, bright green leaves, sprouting from dark, rich soil. The surrounding area is filled with pink and purple blooms that are densely clustered and exhibit delicate petals, set against a softly illuminated window that enhances the plant's vibrant colors. — Be aware that hardiness zones are shifting as the climate changes; you may be in a new growing zone.

Once you know which variety you’re growing, determine your hardiness zone. These zones refer to the average low winter temperature, so they’re helpful measurements when assessing whether or not a plant will survive the winter in your area. Be aware that hardiness zones are shifting as the climate changes; you may be in a new growing zone.

And remember that potted plants are not as cold tolerant as they would be if they were planted in the ground! The soil acts as an insulating layer that helps protect plant roots. Without it, the roots are more susceptible to cold air temperatures. Therefore, it’s best to err on the side of caution when protecting potted specimens.

Winterize Your Potted Hydrangea

A rustic arrangement of flowers featuring rich green leaves and vibrant blooms in pink and white, set against a weathered, textured wall. The foliage adds depth and contrast to the display, while natural light streams in, highlighting the beauty of the blossoms. — Avoid fertilizing in the late summer and fall since this will encourage them to send a new flush of foliage.

Dormant plants have a much better time surviving cold temperatures than actively growing ones. Therefore, one of your jobs is to help your hydrangea slow its growth and enter dormancy before below-freezing temperatures arrive.

First, avoid pruning living tissue in the fall. This is proven to reduce or halt flowering next season. Pruning encourages them to send out supple new growth that is more susceptible to cold damage. Therefore, wait until the late winter or early spring to prune.

You should also adjust your basic care routines to help ease the transition into fall and winter. Avoid fertilizing in the late summer and fall since this will encourage a new flush of foliage that’s susceptible to cold damage. Decreasing the amount of water will also help prepare for a cold winter.

Pay Attention to the Weather

A charming display of various flowers in bright pink hues, surrounded by deep green leaves. The background features a mix of colorful containers and an outdoor deck, creating a lively atmosphere that celebrates nature's beauty. — A good rule of thumb is to protect them when night-time temperatures consistently dip below 45°F (7°C).

Pay attention to the weather and the weather forecast to avoid covering too early in the fall. You want to winterize and protect your potted hydrangeas before your first frost date, so look up your predicted date if you’re unsure when to expect the first blanket of frost. While this date is a good piece of information to have on hand, be aware you should add frost covers well before the first frost.

A good rule of thumb is to mulch and cover when night-time temperatures consistently dip below 45°F (7°C). It’s okay if they experience a one-off cold night, but you should aim to protect them before a steady stream of chilly nights arrives.

Survey Your Options

A cozy setting with a cluster of delicate pink and cream blooms resting atop a soft white surface, complemented by glossy green leaves. The light streaming through nearby blinds casts gentle shadows, enhancing the peaceful indoor atmosphere. — Either bring them indoors to a cool location or leave them outdoors with extra protection.

You have two main options when it comes time to protect your potted hydrangeas from the winter. You can either bring them indoors to a cool location or leave them outdoors with extra protection.

Move Them Indoors

A beautiful arrangement of round, pink flowers adorned with lush green leaves, set on a simple wooden table next to an open book. The warm, natural light filtering in through the window accentuates the delicate textures and colors, creating a tranquil scene. — Place them in a cool location where the temperature remains below 45°F and above 32°F.

If you live in a growing zone that’s below the plant’s cold tolerance, it’s best to bring your hydrangea indoors. Since potted plants are more susceptible to cold damage than those planted in the ground, temperatures in zone 4 can harm potted specimens that are hardy down to zone 3.

Avoid moving your pots to a warm location. Instead, place them in a cool location where the temperature remains below 45°F and above 32°F (below 7°C and above 0°C). A garage, mudroom, or unheated greenhouse often works well. It’s best if the location receives light, but a dark area can also work.

Leave Them Outdoors and Provide Extra Insulation

A rustic garden scene filled with vibrant blue and yellow flowers, intertwined with lush green leaves. The arrangement is surrounded by natural materials, such as burlap and straw, creating a charming, earthy feel that reflects the beauty of nature. — Some suitable options for wrapping the pot include bubble wrap, burlap, and coconut coir mats.

Another option is to leave your pots outdoors and provide them with extra protection from the cold. This is a great choice for heavy pots as well as for gardeners who don’t have access to a suitable indoor area. However, this option is best for hydrangeas hardy to your growing zone.

Ideally, you can move your pots to a protected outdoor location like the side of a building. However, it’s okay if your container is too large to move.

Once your plant is located where it will spend the winter, it’s time to start insulating it. You can use numerous materials to protect your plant from the cold, and one material isn’t necessarily better than the other. Some suitable options for wrapping the pot include bubble wrap, burlap, and coconut coir mats. You can also wrap the pot with a loose-fitting tarp and fill the space between the tarp and container with leaves, straw, or another insulating material.

Regardless of which material you choose, aim to provide at least an inch of insulation. This layer will help protect the plant’s roots from cold air temperatures. If possible, you should place the bottom of your planter on a piece of rigid insulation, a pile of woodchips, or a log.

In most instances, you won’t have to protect the above-ground portion of the hydrangea. Remember, outdoor overwintering works best when the plant is hardy to your growing zone. However, you can wrap the plant’s branches with a layer of burlap or row cover if you’re expecting an extra cold night.

Water Sparingly

A gardener dressed in a green apron, gently tending to a collection of colorful flowers, which showcase bright blue and pink petals. The surrounding foliage is lush and green, with light illuminating the scene, reflecting the joy of nurturing nature. — They use much less water during the winter, and too much water can quickly lead to wet soil and rotten roots.

Regardless of whether you leave your potted hydrangeas outside to winterize or you bring them indoors for protection, be careful to avoid overwatering. They use much less water during the winter, and too much water can quickly lead to wet soil and rotten roots.

In most circumstances, outdoor specimens can survive the winter without any irrigation. Indoor pots may require some water, but watering once a month is generally sufficient. If the soil feels moist, you don’t need to water.

Move Outdoors After Last Frost

A stunning arrangement of pink blooms complemented by rich green leaves, set in a garden bursting with life. The background reveals other plants and flowers, creating a vibrant tapestry of colors and textures, enhanced by dappled sunlight filtering through nearby foliage. — Moving them outdoors when it’s still cool allows them to slowly transition into spring.

Once your last spring frost has passed and nighttime temperatures are consistently above 45°F (7°C), you can prepare for spring! Move indoor potted hydrangeas outdoors, and remove any winter protective coverings from those that spent the winter outdoors.

Moving them outdoors while it’s still cool allows them to slowly transition into spring. Plus, it ensures they receive full sun as they form new leaves and buds.