I confess, I don’t do much to prepare my hydrangeas for winter.
Most bloom on new wood, which means flower buds form in the spring and don’t need to overwinter. Or they’re the re-blooming types of hydrangeas, which form flower buds on old and new wood. That means if flower buds are killed off over the winter, ones form on the new wood. So I’ll still get some blooms, just later in the year.
I don’t even prune my hydrangeas in the fall. But if your hydrangeas depend on overwintering, you might need to do a little more work to prepare them for the coldest season.
Can Hydrangeas Survive Frost?
Yes. Some varieties are hardy only to U.S. Department of Agriculture Plant Hardiness Zone 6, while many others can survive the colder winters of Zone 4. Even a potted, blooming hydrangea from a florist can survive outside with proper care.
Most of these florist-grown types are big-leaf hydrangeas, Hydrangea macrophylla. They can be hardened off by gradually exposing them to outside conditions in the spring or early summer, then planted in the garden. They’re generally hardy enough to grow in USDA Zones 6 through 8. I’d even try growing them in USDA Zones 4 and 5 with some winter protection.
Why Winterize Hydrangeas?
Most garden hydrangeas don’t need much extra attention before winter. Most don’t even need to be pruned in the fall because their flower buds form in the spring.
The exception to this is Hydrangea macrophylla. Depending on the type of flowers produced, these are commonly called mophead or lacetop hydrangeas. They form flower buds in late summer and may need winter protection to ensure they flower the following year.
When To Winterize Hydrangeas
In USDA Zones 5 and colder, begin winterizing big leaf hydrangeas once temperatures turn consistently cold. Depending on where you live, this could be as late as the end of November.
Tools and Materials for Winterizing Hydrangeas
If you need to protect your big leaf hydrangeas from cold winters, you can easily do it with a few basic supplies:
- Chicken wire or other pliable wire fencing to make a cage around them.
- Wire snips to cut the chicken wire.
- Burlap fabric to wrap around the cage.
- Shredded leaves to cover the ground.
How To Winterize Hydrangeas
For all hydrangeas, make sure they’re well-watered through the fall. If you don’t get adequate rain, you may need to water your hydrangeas, especially if you planted them in the last year.
Make sure to cover the ground around them with two to three inches of mulch. This helps to moderate soil temperature and prevent freezing and thawing, which can expose roots and cause them to dry out.
How to Winterize Hydrangeas Grown in Containers
Hydrangeas grown in winter-proof containers can be overwintered in place if the containers are too large to move. Add mulch and make sure the soil hasn’t completely dried out before the ground freezes. If the soil is dry, water lightly.
If you can safely do so, move the containers to a more sheltered location to protect them from strong winds but still get some sun and moisture.
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