When azaleas (Rhododendron spp.) are in bloom, there isn’t anything else quite like them in the garden. And with so many varieties to choose from, there’s an azalea that’s perfect for just about any landscape.
There are types that bloom in spring, summer, or fall; deciduous and evergreen varieties, as well as some cultivars bred to rebloom.
Most species plants can be grown in Zones 5 to 9, but breeders have come up with cold-tolerant hybrid cultivars that are hardy to Zone 3.
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If you need a refresher about how to grow azaleas, check out our guide. In this article, we’re going to discuss what, if anything, you need to do to protect your shrubs during the winter months.
The biggest threat to your azaleas is extreme weather fluctuations. An extended freeze generally won’t bother them much if the temperatures have been dropping gradually, but a sudden plummet can cause damage.
Whether you’re growing them in containers or in the ground, there are a few protective measures you can put in place to ensure your azaleas are safe over the cold months.
Here’s what I’ll cover:
Winter care largely depends on your region’s USDA Hardiness Zone.
Those who live in an area that rarely or never freezes will have a different set of tasks ahead of the winter months from gardeners who live in an area that freezes during the winter.
Speaking of Zones, make sure that you’re growing an azalea that is appropriate for your Zone.
You can find varieties that thrive in Zones 4 to 9, so don’t make things harder on yourself by selecting one that isn’t suited to your area.
Hybrids in the Encore or Northern Lights series were bred for cold climates, so consider one of these if you live in Zones 4 and below.
If your region experiences frigid winters outside of their hardness range, you can grow your azaleas in containers and bring them indoors during the extreme weather.
Keep in mind that temperature tolerance alone doesn’t necessarily guarantee an azalea will do well in harsh winter conditions. For example, a variety that’s capable of surviving down to 20°F might be sensitive to drying winds in the winter.
If you want to be extra safe and protect your shrubs from inclement weather, consider growing them in an area with morning sun and dappled shade in the afternoon like under a tree or canopy that will help to mitigate harsh conditions.
Next, let’s discuss how to prepare for winter.
Preparation
Azaleas don’t go entirely dormant for the winter months, like some species that die back to the ground. Many azaleas are evergreen, and the roots continue to grow.
Your winter prep starts in advance of the cold season, you want to stop fertilizing around mid to late summer, depending on your region.
Your plants should have long finished flowering and putting out new growth by this point, so they don’t need any additional food. You don’t want to encourage your azalea to put out growth when it should be hunkering down for the winter.
A few years ago, I planted a few new azaleas, and we had an unusually dry and hot summer.
One was in a good amount of shade and received moisture from the irrigation system, while the other didn’t and it was in full sun.
That winter, we had a prolonged freeze that really challenged a lot of my garden specimes. The azalea that had been stressed all summer died, while its nearby friend survived just fine.
The moral of the story is that you shouldn’t underestimate the importance of keeping your plants healthy throughout the year.
You should continue to water every week or two leading up to the winter if fall in your area is hot and dry. Azaleas need lots of moisture to take up the nutrients they need to survive through the cold months.
Make sure the soil is nice and moist before the cold sets in. If there is a freeze on the horizon, water as soon as you know it’s coming.
I’m not suggesting that you overwater and turn the ground into a soggy, mushy mess.
You want to give the appropriate amount of moisture for your particular type of azalea, but just ensure that you keep doing so even as the winter approaches.
Add four to six inches of mulch from about an inch away from the stem to the drip line of the shrub.
The drip line is the area that extends to outmost parts of the canopy, where the rain would run off and fall to the ground. Any organic mulch is fine, so feel free to use your favorite wood chip, well-rotted compost, or leaf litter.
If you live in a cold region, I prefer to use whole, deciduous leaves because they create heat as they break down, adding just a hint of warmth to the soil that your plants will appreciate.
If your mulch tends to migrate thanks to wind or critter traffic, use something heavy like wood chips.
Finally, if your garden tends to become a rabbit or deer buffet in the winter, protect the plant with some fencing.
A four-foot-tall barrier of chicken wire next to but not touching the foliage is usually enough r to keep hungry critters away.
In-Ground Azaleas
Beyond watering and mulch discussed above, you don’t need to do much to protect your azaleas during typical weather. By typical, I mean the sort of weather that your area experiences every winter.
But say, for example, that you have an extremely dry period that is unusual for your region. In that case, get out there and give your plants some water to help them make it through.
They won’t need a ton of water since they’re at least partially dormant, but just ensure the soil doesn’t dry out completely.
On the other end of the spectrum, you also need to watch out for very cold weather.
If you typically have freezing, snowy, or windy winters, and your plants are used to it you don’t need to worry when that occurs. Your plant is able to adapt to the conditions.
When a hard freeze occurs, the leaves may look droopy, curled, and sad. Don’t worry, this is a defense mechanism and it’s perfectly normal. Because the ground is frozen, coupled with drying winds, the shrub can’t take up moisture.
You can help to reduce or limit the amount of wilting and curling by spraying your plants with an anti-desiccant like Wilt-Pruf, available via Amazon.
When temperatures drop to about 40°F, follow the manufacturer’s directions and spray the the foliage and branches thoroughly.
You can also help protect your plant by providing a screen to block drying winds. Anything from a sheet of frost cloth affixed to a frame to a beach umbrella secured in place will do the job.
Finally, don’t touch the plant. Any movement at this point will cause the water inside the stems to freeze and stop moving.
An azalea in temperatures as low as 28°F can still move water throughout the stems and leaves, but if you were to shake the leaves, maybe while trying to remove snow, it would cause the water to stop moving. This leads to drying out.
When the temperatures increase, the leaves will perk back up. Don’t water your plant and don’t try to manually thaw it out using Christmas lights or anything like that. Just let Mother Nature do her thing.
The exception to this is if you don’t normally experience hard freezes and your shrub hasn’t had time to acclimate to colder conditions. In that case, you’ll want to provide a little extra support by covering it in frost cloth or burlap.
When covering your plant, you have two options. You can either wrap the shrub itself, taking care not to break any branches, or you can erect a frame around the plant and put the cloth over that.
The first method should only be left in place for a night or two and then removed. If you leave too long, it will end up trapping water and cause fungal issues.
If you want to leave the cloth in place for an extended period, you must build a wood or wire frame to provide some support.
Container Plants
When you grow azaleas in containers, the root system is less insulated than it is in the ground and so is more susceptible to freezing and thawing, which can damage plants.
My suggestion is that you treat your plant as though you are in one Zone colder.
So, if you live in Zone 8, pretend like your azalea is in Zone 7 and plan accordingly. That means you should buy a variety that can survive in Zone 7.
When cold weather is on the horizon, protect your plant by wrapping the container in burlap or wool to provide an extra layer of insulation. You should also add a few inches of mulch to the top of the soil, but don’t let it touch the trunk.
If you have extreme weather, you can cover the plant with frost cloth or you can take it into a protected area.
As with those growing in the ground, if your azalea is acclimated to the typical conditions of your area, you don’t need to do anything, beyond water and mulch.
It’s only when extreme weather occurs that you need to worry. Also, the curling and wilting of the leaves that occurs when the temperatures drop is totally normal, and you don’t need to do anything about it.
Growing your plants indoors all winter isn’t really an option. The only type that can survive indoors are florist’s azaleas (Rhododendron simsii). All others need a certain number of hours below 40°F to develop flower buds.
You can certainly move a container-grown specimen into a garage, shed, or basement during an extreme weather event, but it needs to remain outside for the majority of the time.
Addressing Cold Damage
It happens to everyone at some point. You do your best to support your plant during the cold weather, but Old Man Winter has the upper hand, and your shrub sustains damage. Now what?
First, let’s discuss what cold damage might look like. The most common symptoms are brown patches on the leaves and brown or dead buds.
You might also see discolored foliage and split bark. Sometimes if a freeze occurs early in the season, the newest growth will be killed off.
In the worst case scenario, if there is an early hard freeze that occurs before the plant has time to adapt to the changing weather or if the plant is young, it might be killed.
Assuming your shrub survived but has some unsightly winter damage, the next step is to help restore it to health. But don’t break out the pruners just yet.
Allow the azalea to put out new growth before you consider pruning. Often, the plant will shed the damaged leaves and you won’t need to do much, anyway.
When the new foliage emerges, you can assess if there are any dead branches or stems. You can also see whether any of the brown buds survived. Sometimes, it’s just the outer layers of the buds that are impacted and they’ll recover just fine.
At this point you can prune off any dead or heavily damaged leaves and any dead branches. Cut the dead areas back to a few inches into live growth.
Your azalea might not bloom the year following an extreme freeze event, and that means the developing flower buds were damaged. Unless the plant is damaged again, it should bloom like normal the following year.
Over the next few years, new foliage start to fill in the dead spots and the plant will look as good as new.
Time to Bundle Up
Come winter, part of putting the garden to bed can include protecting species that are susceptible to winter damage.
That might mean winterizing your azaleas. No problem! It’s a little bit of work for a big payoff.
What kind of azalea are you growing and where do you live? Let us know your set-up and how you intend to protect your plants in the comments section below!
And for more azalea-growing know-how, be sure you read these guides next:
