9 Winter Hydrangea Care Tips
Although bare and leafless, hydrangea stems work throughout the winter to prepare their spring blooms. Give them extra care this cold season so they produce dozens of flower clusters next year! These nine winter care tips from seasoned gardener Jerad Bryant will ensure your hydrangea stays safe and sound despite recurring frosts.
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Most gardeners can get away with not protecting their hydrangeas for the winter season. This is especially true if you’re growing cold-hardy species like smooth or panicle hydrangeas. These types adapt well to freezing temperatures and frequent snowfall.
If you’re growing hydrangeas that bloom on old wood, like bigleaf, ashy, or oakleaf species, giving them extra care during the cold months protects their budding blooms. They produce flower buds low on their stems from fall through winter, and the buds need protection from hard frosts or excess debris.
No matter which type of hydrangea you’re growing, some winter care helps these shrubs perform their best. Adding mulch, maintaining consistent moisture, and protecting plants from hard frosts will guarantee they survive this season and thrive the next.
Bring Potted Hydrangeas Inside
While hydrangeas are reliably frost-hardy in the ground, they’re moderately frost-tolerant in containers. Containers keep the roots aboveground, where they’re subject to chilly air that’s common from October through March.
Rather than leaving potted hydrangeas in the cold, you’ll want to move them to a site where they can stay dormant and cool. A garage, cold room, porch, or protected patio is ideal. Outdoors, placing the pots close to your home’s walls is another option, as the heat radiates outward from the walls and protects your shrubs.
Hoop houses, cold frames, and greenhouses are other options that work well for insulating dormant hydrangeas without awakening them from their slumber. The goal is to keep the shrubs cool, moist, and away from heaters with hot drafts. If all else fails, try burying the potted hydrangeas outdoors so they receive natural insulation from the soil.
Protect New Transplants
It’s best to transplant hydrangeas in the fall, at least a month before your first hard frost, to ensure they have ample time to adapt to the site. New transplants need more care than established, mature specimens. Protect them this winter and they’ll survive many winters afterward without much protection.
After planting, check to make sure your shrub is sitting at a proper height in its planting hole so that the root flare lines up with the soil line. The flare point is where the trunk branches into multiple, thick roots. You want it to sit perfectly so the roots don’t expose themselves and grow directly below the surface.
Although it’s better to prune hydrangeas in spring or early summer rather than fall, you can prune new transplants to keep them from growing top-heavy. Snip a few inches off the top of the stems to keep the branches proportionate to their small root balls.
Insulate the Soil
Both new transplants and mature hydrangeas appreciate a blanket on top of the soil. Mulch, like compost or leaf mold, is an organic blanket that decays while it insulates the ground. It’ll protect plant roots, beneficial fungi and bacteria, and soil organisms like worms. As it decays it’ll feed the plants, animals, and microorganisms with delicious nutrients they need to thrive.
You have a few options when it comes to mulching materials. The best mulches are the easiest ones to find in your garden. Fall leaves, leaf mold, compost, and wood chips are excellent options for soil insulators. They are common in nature and work well with soil organisms. Snow is another great option if it falls before hard frosts arrive in your region.
If it’s difficult to source these mulches, you can use organic mixes from your local garden nursery. Avoid inorganic mulches made of plastic or synthetic fibers, as these persist in the ground and disrupt air and water flow.
Maintain Consistent Moisture
While hydrangeas are dormant, their roots are alive! They grow beneath the soil surface, where temperatures stay considerably warmer than ambient air. If you let these roots dry out, your shrubs will be less frost-hardy and susceptible to freeze damage.
Ensure the soil near the roots stays moist throughout the cool months. Excess moisture causes issues, too, so you’ll want to avoid watering already wet dirt. You want it to be moist, not soggy, like a wrung-out sponge.
The same rule applies to container shrubs. Keep their soil moist, not soggy, and ensure they don’t dry out completely. Water provides insulation from the cold, making it more difficult for frost to penetrate the root zone.
Wait to Prune and Fertilize
Although hydrangea stems are bare and easy to see in the winter, it’s best to wait until spring or early summer for pruning. Pruning can lop off next year’s blooms. It can also open up wounds that allow frost to creep into your shrub.
When to prune a hydrangea depends on its type. Old wood bloomers produce flowers on last year’s growth, while new wood bloomers flower from fresh growth. Prune old wood bloomers after they blossom from spring through summer, and avoid pruning them from fall through spring.
New wood bloomers, like smooth and panicle hydrangeas, produce flower buds after significant leafy growth in spring. Avoid lopping their stems in late spring; prune them from summer through fall, or late winter through early spring before they awaken from dormancy.
Fertilizing, like pruning, isn’t a winter task. The shrubs won’t need fertilizer until after they awaken from their winter slumber. Wait to fertilize until you see hydrangea stems sprout new leaves or flower buds.
Use Frost Cloth
Hard winter frosts threaten frost-tender hydrangeas. With a little preemptive maintenance, your shrubs can survive ice and snow storms without issues. Use snow as a natural cover if it falls readily in your region. Otherwise, there are a few options to choose from for cold protection.
Frost cloth is an excellent tool that’s easy to source and use. It’s a thin layer of cloth that provides a layer between your shrub and the chilly air. Simply drape it over the stems at dusk and weigh down the ends with something heavy. You may leave the cloth on as long as you need frost protection, up until the hydrangeas awake from dormancy in early spring.
Do you have extra bedsheets lying around? They make ideal frost cloths and are easy to find. Use them as frosty nights approach your garden. Remove the cloth on bright, sunny days to let sunlight warm the ground.
Wrap Hydrangeas in Burlap
Without frost cloth or bedsheets, burlap makes an excellent frost protectant. It requires a different approach, as you’ll wrap the shrub in it with some space between the burlap and the stems. Pack this space with dry leaves, straw, or similar materials to insulate and protect the hydrangea from frigid winter weather.
Burlap alone grows heavy when it’s wet, unlike frost cloth. It also lets in much less light than cloth does. Packing the inner space with leaves helps avoid structural damage. To prevent excessive shading of your hydrangea, remove the burlap on warm days in late winter and early spring as it awakens from dormancy. Apply it again only on nights you expect frost.
Burlap offers extra insulation, more so than frost cloth. If you live in a cold zone or are growing a frost-sensitive hydrangea outside of its preferred hardiness zones, it’s a great option for supreme protection. Use this chart to determine what type of hydrangea you have and which zone it’ll survive in:
| Common Name | Scientific Name | Hardiness Zones |
| Climbing Hydrangea | Hydrangea anomala | 4-8 |
| Smooth Hydrangea | H. arborescens | 3-9 |
| Rough-Leaved Hydrangea | H. aspera | 7-9 |
| Bigleaf Hydrangea | H. macrophylla | 6-11 |
| Panicle Hydrangea | H. paniculata | 3-8 |
| Oakleaf Hydrangea | H. quercifolia | 5-9 |
| Evergreen Climbing Hydrangea | H. integrifolia | 7-9 |
| Mountain Hydrangea | H. serrata | 6-9 |
Make a Protective Cage
A cage works in tandem with dry leaves or straw to protect your budding hydrangeas. It requires more setup, but it’s a foolproof way to offer frost defenses. Start by staking some posts around your shrub. Use metal, bamboo, or whatever you can get your hands on. Wrap wire netting around the wooden stakes to create a barrier.
Inside the barrier, place the dry leaves and straw so they cover your shrub completely. They’ll insulate and warm your hydrangea, keeping it warmer than the surrounding air. Straw or hay are two other materials that work in place of leaves and straw.
Protective cages, like burlap contraptions, are supreme defenses against the cold. Choose this option rather than frost cloth if you garden in cold zones with recurring hard frosts.
Clear Branches of Debris
Debris may fall on your budding hydrangea during chilly winter storms with fast winds. Branches, leaves, and ice or snow can create a thick layer on upper branches and weigh them down. This is more of a danger for mature specimens than young transplants, as old hydrangeas have thick stems that can break under pressure.
The best way to avoid damaging your hydrangea is to inspect it after storms. Manually remove debris covering the upper stems if it’s weighing them down. This is difficult to accomplish for climbing types that scale tree trunks! Simply leave them be and let their stems break and recover—climbing hydrangeas are vigorous growers and will quickly heal.
Frequently Asked Questions
What does winter care for a hydrangea tree look like?
Hydrangea trees have a single thick trunk with many thin branches above the ground. You may insulate the trunk during the winter, but take care not to make it too wet. Excess moisture can lead to trunk rot.
How do you trim hydrangeas in winter?
Avoid pruning hydrangeas during winter. Wait until late winter or early spring to prune new wood blooming types, and prune old wood bloomers after they finish flowering.
Can hydrangeas survive winter in pots?
Yes, they can! If your hydrangea’s species is particularly cold-hardy in your zone, you can keep it outdoors. Otherwise, bring it indoors, or bury it, container and all, in an open spot in your yard. The ground will protect and insulate your potted hydrangea.
