5 Signs Your Hydrangea Needs Extra Winter Protection

It’s a chore to cover up shrubs in the winter, and you may find yourself wondering whether you have to or not. Hydrangeas fare well from hardiness zones 3 through 9, although certain species work better than others in cold or warm regions, and some require winter protection.

Bigleaf varieties are the most common type that gardeners grow and retailers sell, although rarer species are making the ranks in North America. Native species are growing more popular, while new hybrids and varieties emerge annually with traits like reblooming, frost tolerance, and flowers with new color combinations.

No matter which type you choose, selecting one that works well with your climate is important. It helps you avoid winter garden maintenance while it’s cold outside. It also ensures your shrub will bloom without issues for years!

5 Signs Your Hydrangeas Need Winter Protection

We’ll cover which hydrangeas to protect, how to let nature work for you, and what measures you can take to ensure they stay safe and warm through the winter. Without further ado, here are five signs your hydrangea shrubs need extra winter protection. 

It’s Not Frost-Hardy

Some species are exceptionally frost tolerant, like smooth and panicle hydrangeas, while others need warmer winters, like evergreen climbing varieties. The shrubs require extra protection if they grow outside their preferred hardiness zone. Use this chart to see which types perform best in your garden. 

Your shrub will need protection if it’s not meant for your hardiness zone. Zone 3 gardeners should stick to smooth and panicle hydrangeas and their cultivars, as they’re the most tolerant of extreme winter weather. You may grow types that aren’t meant for your zone so long as you know you’ll need to give them a little extra care during the cold seasons.

New Buds Are Forming

Old wood blooming species form buds that swell in late winter and early spring. If hard frosts occur with frequency until late spring, they may threaten your hydrangea’s forming flowers. Species that bloom on new wood are safe, although the frosts may kill their growing sprouts and delay their blooms until later in the growing season. 

It’s better to be cautious rather than free-spirited when deciding on winter protection for your hydrangea. Deciduous species lose their leaves in the fall, meaning you can cover them without issues until their buds open up. You won’t get in the way of natural processes like photosynthesis in the dead of winter. 

If you don’t see new buds forming by late spring, chances are your shrub’s stems froze to the ground. They’ll grow back, although they won’t have flower clusters this year. Frost-zapped shrubs need a year or longer to recover the energy from their lost buds. 

Frosts Are Still Occurring

Hard frosts can freeze the tender buds! Hydrangeas are hardy, although they still suffer damage from icy winter storms if they are left without protection. Snow is beneficial as a mulch but damages the shrub if it stays on the branches like ice. Ensure your shrubs stay ice and snow-free on their upper stems for the highest chance of winter survival. 

Some zones have few, if any frosty nights. Growers in these regions shouldn’t worry about protecting their shrubs after their last average frost date. 

The main seasons of danger are early spring and late fall. Surprise frosts sometimes linger into late spring. High temperatures and ample sunlight convince the shrubs to break dormancy, then surprise frosts move in and zap the tender foliage! Hydrangeas may be late to enter dormancy during the fall. Early frosts harm their tender stems while they’re green and still active. 

It Blooms On Old Wood

Most hydrangea species bloom on old wood, a few bloom on new growth, while other newer types flower on old and new wood! If you have a reblooming hydrangea you’ll want to treat it as an old wood bloomer, that way you protect both sets of flowers that open on it next year. 

Smooth and panicle types bloom on new wood, and they’re also the most cold-tolerant of all species! Grow these hydrangeas without winter protection from zones 3 through 8. They’ll sometimes survive in zone 2 with extra protection.

Old wood blooming species include mountain, climbing, evergreen climbing, bigleaf, rough-leaved, and oakleaf hydrangeas. These species and their cultivars think about flowering starting in late summer. They form spring buds that open up into flowers and foliage next year. Give them some protection to ensure they stay safe despite frosty temperatures. 

It’s A Mature Specimen

Old hydrangea shrubs may require some covers. Although mature, tall specimens are more at risk of frost damage. The stems extend into the air where temperatures are lower than at the soil level. If buds form on the ends of these stems they’ll be subject to undesirable weather.

You have two options when it comes to mature hydrangeas: prune them during the correct season, or protect their buds this winter. Prune old wood bloomers after they flower in spring or summer, and prune new wood flowering species in fall or spring. 

How to Protect Your Hydrangea

If you’re choosing to protect your plants so they look their best next year, you have some options to choose from. Growers with frequent snowfall should let the snow act as mulch. Gardeners in other regions can use everyday materials to make a protective layer between freezing temperatures and their sensitive hydrangeas.

Snow Cover

Snow is nature’s way of protecting sensitive plants! It insulates the ground, keeping the soil warm and protecting growing roots. It also works well for budding hydrangeas, protecting their lower stems from frosty air. The snow must fall before your first frost of the season to be an effective mulch. If frosts occur first, they may harm tender flower buds before the snow protects them.

Burlap

Burlap is a cheap and effective material for insulating your hydrangeas. Wrap the stems with the stuff, leaving some distance between the burlap layers and your shrubs’ stems. Pack the inner space with dry leaves or straw, and leave it be until spring warmth arrives. The burlap and leaves protect, warm, and insulate flower buds while they swell. 

Cage with Straw

Another cheap option is to use a cage or chicken wire with lightweight mulch like straw, leaves, or hay. Wrap the metal wiring around the shrubs, leaving space between their stems and the cage. Then, pack the inner spaces with lightweight mulches. The mulch creates a blanketing effect, warming your shrub despite freezing temperatures. 

Frost Cloth

The easiest way to protect your hydrangeas is to throw frost cloth on them before you anticipate icy weather. This is what we use in wholesale nurseries to protect sensitive shrubs overnight. The cloth provides a layer between the icy air and the stems, allowing the space underneath to stay warmer than the surrounding air.