Quick Summary: Yes, blueberry plants can survive winter in pots, but roots in a container freeze far more easily than roots in the ground, so add one to two zones to your plant’s hardiness rating. Bury the pot, mulch and wrap it, or move it to an unheated garage or shed so it still gets the winter chill it needs to fruit. In-ground bushes need less help, but they do need deep fall watering, mulch, and a wire cage against rabbits. Best time to act is after the leaves turn red and before the ground freezes.
Jump to: Hardiness zones | Winterizing Blueberry Pots Outdoors | Winterizing Blueberry Pots Indoors | Transitioning Indoor Pots to Outdoors in Spring | How to Overwinter Blueberry Bushes in the Ground| Protecting from Pests | FAQ
Blueberry plants grown in containers will thrive in the summer but in many climates they will need a little extra care in winter to prevent their roots from freezing.
Here’s how to winterize a potted blueberry bush, whether you’re overwintering it outdoors or in a garage or shed, plus what to do for bushes growing in the ground.
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Hardiness Zones for Protecting Blueberry Plants
A blueberry plant in a pot needs to be rated one to two hardiness zones colder than your garden’s zone to stay outdoors over winter, because roots in a container aren’t insulated by the ground.
Hardiness does vary between different types of blueberry shrubs, so if you’d like to overwinter yours, the first step is to find out the lowest winter temperature that the variety you are growing can withstand outdoors.
Based on this, you can decide whether it can stay outside in your climate or if it’ll be better off in a shed or garage.
When it comes to protecting a blueberry plant grown in a pot in winter, it’s important to remember that they’re not as hardy as blueberry plants grown in the ground where their roots are insulated by plenty of soil.
So once you have identified the variety, take the USDA hardiness zone your plant is rated for and then add 1-2 zones if you want to overwinter it “outdoors” in a pot.
For example, if your blueberry bush variety is listed as hardy to zone 4, that means it will survive “in the ground” to the typical temperatures of zone 4. If it is in a pot however, it will only survive outdoors to zone 5 or 6.
Zone 3 is the coldest winter weather most hardy blueberry cultivars can handle, although there are a few wild blueberry bushes that are hardy to Zone 2.
There are five basic “categories” of blueberry plants:
- Lowbush: minimum Zone 3 (so Zone 5 in a pot); a few varieties down to Zone 2.
- Half-high: minimum Zone 3 (so Zone 5 in a pot).
- Northern highbush: minimum Zone 4 (so Zone 6 in a pot); a few varieties down to Zone 3.
- Southern highbush: minimum Zone 6 (so Zone 8 in a pot); a few varieties down to Zone 5.
- Rabbiteye: minimum Zone 7 (so Zone 9 in a pot).
| Category | Ground Zone | Pot Zone |
|---|---|---|
| Lowbush | Zone 3 | Zone 5 |
| Half-high | Zone 3 | Zone 5 |
| Northern highbush | Zone 4 | Zone 6 |
| Southern highbush | Zone 6 | Zone 8 |
| Rabbiteye | Zone 7 | Zone 9 |
Based on this hardiness information, you can decide whether to overwinter your potted blueberry shrubs indoors or outdoors.
Know also that blueberries need a dormancy period. This means you can’t keep them in a warm place like your living room during winter.
Tip: If you live in a warm climate like Florida, you may only be able to grow Southern Highbush varieties or Rabbiteye. The others just need more cold to grow properly!
How to Winterize Blueberry Plants in Pots Outdoors
To winterize blueberry plants in pots outdoors, you will need to protect the roots. Best practice is to bury the pot or pack mulch around it, cover the plant in the coldest weeks, and water lightly once a month if there’s no snow.
The shallow blueberry root system can really suffer and even die off if it ends up freezing, so it’s important to prevent this from happening.
This especially applies if the plant is in the type of container that doesn’t offer much in the way of protection (i.e., thin plastic or terra cotta).
A small, single-walled thin plastic pot exposes the roots far more than an extra-large and thick container made of fiberglass.
Here are some steps you can consider to help your potted blueberry bush survive being outdoors in winter:
#1. Bury the Container and Roots
The best thing you can do for a blueberry shrub when overwintering outdoors in a pot is to bury the container in soil.
Just dig a hole that matches the container size, pop the plant in there, and cover it in such a way that the roots are insulated but the stem is exposed.
If you can’t bury the pot, try to place it in a sheltered position. Pick the north or east side of a building if you can. A sunny south wall can warm the plant enough on mild days to wake it up too early.
#2. Mulch
If you can’t bury the pot, set it inside a larger container or a ring of chicken wire and pack the gap with straw or shredded leaves.
As you’ve probably concluded by now, overwintering blueberries in a pot outdoors is all about insulation.
Mulching is a great way to do this: you can add up to 8″ of straw, pine needles, shredded bark, or leaf mulch in and around the container to help insulate your plant.
#3. Cover the Plant
Wrap the container first, then cover the top of the plant if your site gets harsh winds.
There are loads of different pot covers and even mini greenhouses for sale that you can use to help protect your blueberry shrub. Even just a layer of plastic, bubble wrap, burlap, or horticultural fleece can be helpful!
If you use a mini greenhouse or clear plastic cover, keep it out of direct sun or vent it on sunny days. It can warm up enough to wake the plant early, and any new growth will be killed by the next hard freeze.
#4. Watering
During the winter months, your blueberry bush won’t require nearly as much water as in summer. Dormant plants barely need any water, although you shouldn’t let the soil get bone dry either.
A layer of snow should be fine to keep your plant hydrated.
If there is none and if it hasn’t rained in a while, it’s a good idea to lightly water once a month. No fertilizer, however.
Tip: Dormant blueberry shrubs can look dead during winter and early spring, with brown branches and no green in sight. Even if you’re sure yours has kicked the bucket, wait well into spring to throw it out. It may just surprise you.
Overwintering Blueberry Plants in Pots Indoors
Here in Minnesota (zone 4b), I move my potted blueberries into an unheated garage once they go dormant in late fall, after the leaves turn red. I water them two or three times over the winter and move them back outside in early spring while they’re still dormant, because plants that bloom early in the garage have no pollinators around.
Bring a potted blueberry inside only if your winters are colder than its pot zone in the chart above, and even then, choose an unheated garage or shed rather than the house.
Tip: The best time to move them indoors is late fall when the temperature has dropped and their leaves are no longer green (most varieties have leaves that turn dark red or maroon).
Finding the Right Location
As mentioned above, you can’t just put a blueberry plant in your living room for the winter. They need a dormancy period to bud and flower properly next year.
Chill needs vary by type. A chill hour is most commonly defined as an hour spent between 32 and 45 °F. Low-chill southern highbush varieties need as few as 150 to 300 hours, rabbiteyes roughly 350 to 700, and northern highbush 800 or more.
As such, if you want to keep a blueberry indoors for winter, it needs to be in an unheated spot so it can start accumulating those chill hours.
A garden shed or garage is perfect, as it offers protection against the wind and harsh weather conditions, but still gets cool enough for the shrub to go fully dormant.
I overwinter my potted plants in my garden shed which has windows and stays around 45 degrees F most of the winter.
Light & Water Needs
One issue many gardeners run into when it comes to overwintering potted blueberries indoors is the lack of light. Most sheds and garages don’t have much in the way of windows.
A dormant blueberry has dropped its leaves and needs very little light, so a dark garage is fine for the coldest months. When the buds begin to swell in late winter, move it next to a window or start setting it outside on mild days.
As for water, your plant will not need much water over the winter, but it shouldn’t stay bone dry all winter either. Check the soil occasionally; if you stick a finger into it and it feels dry down to one inch, give the shrub a drink. Don’t overdo it, though!
You can also re-pot or prune your shrub during this dormant time. Late winter is the perfect time to prune, before the buds swell. It helps to get the best possible harvest next year.
Overwintering other potted plants too? My guide to overwintering potted plants in cold climates covers lavender, rosemary, citrus, strawberries, and more.
Bringing Overwintered Plants Back Outside in Spring
If your blueberry bush has just spent a few months in a nice sheltered shed, it’s best not to move it straight back outside once spring rolls around.
After all, it’s probably not used to outdoor weather conditions (wind, hard rain) anymore, nor will it be able to handle sudden large amounts of sun.
Additionally, to avoid shocking the plant, stretch the transition from indoors to outside over at least a week or two.
Place it outside for a few of the warmest hours of the day at first, and be sure to pick a more sheltered spot in the beginning.
How to Overwinter Blueberry Bushes in the Ground
Blueberry bushes planted in the ground are much hardier than potted ones. The soil insulates the roots, so northern highbush, half-high, and lowbush varieties usually come through a zone 4 winter with only a little help. The main threats are drying winds, freeze and thaw cycles, and hungry animals (see below).
Do in-ground bushes need covering? Established, cold-hardy bushes don’t. Covering helps young plants in their first winter, bushes on a windy site, or any bush when a hard freeze hits after the buds start to swell in spring. Here are the keys to overwintering a blueberry bush in the ground:
- Water deeply through fall until the ground freezes, especially after a dry autumn.
- Spread 3 to 4 inches of pine needles, wood chips, or shredded leaves over the root zone. Blueberry roots are shallow, and mulch evens out the soil temperature. My guide to mulching a vegetable garden for winter walks through materials and timing, and the same approach works around blueberries.
- Stop fertilizing by midsummer so the bush isn’t pushing tender new growth going into fall.
- Protect the canes from rabbits and voles. Rabbits chew stems down to the snow line, and voles girdle them under the snow. A cylinder of chicken wire or hardware cloth around each bush, set a few inches into the soil, keeps them off.
- Screen young or exposed bushes from wind with burlap stretched between stakes, not wrapped tightly around the branches.
- Leave the snow in place. It’s excellent insulation. Just knock heavy, wet snow off the branches so they don’t break.
Protecting Blueberry Bushes from Deer and Rabbits
Hungry animals rank right up there with the worst problem for blueberries. Deer will eat all of the tips of mature plants in the winter and rabbits will eat the tender branches of new plants. Then when the bushes do start producing the fruit, it’s a race with the birds to get the blueberries.
Over the past 20+ years I have tried everything suggested by every gardening site. For me, the only thing that works is dogs to chase the deer away in the winter and netting to prevent the birds from eating the crop in the summer.
Both are actually quite effective. My rescue dog absolutely loves to chase the deer. He never catches them of course, but it’s enough of a nuisance that they eventually stay away. And boy does he feel like a tough guy.
Netting is a drag to put up for prevention of bird scavenging, and you do catch some birds in it, but it is effective.
FAQ
In zone 4 or colder, like here in Minnesota, move it into an unheated garage or shed once it goes dormant. In milder zones, bury the pot or wrap and mulch it outdoors against a north or east wall. Either way, water lightly about once a month and don’t fertilize until spring.
A potted blueberry can spend the whole winter, four to five months here in Minnesota, dormant in its pot and come through year after year, as long as the roots stay insulated and never dry out completely. With repotting every year or two, potted bushes live 10 to 15 years or more. My guide to growing blueberries in pots covers container size and lifespan.
Only into an unheated space like a garage or shed, and only if your winters are colder than the plant’s pot zone. A heated house keeps it from going dormant, and it won’t fruit well the next year.
Potted bushes left outside in cold zones, yes, starting with the container. Established in-ground bushes usually don’t need covering unless they’re young, exposed to wind, or facing a hard freeze after the buds swell.
After the leaves turn red and the plant goes semi-dormant, but before the ground freezes hard. In Minnesota, that’s usually late October into November.
A little. Check the soil every few weeks and water lightly when it’s dry an inch down. Snow cover usually provides enough moisture outdoors. Don’t fertilize until spring.
In the ground, if your soil is acidic and drains well, because the roots have more room and more winter protection. Pots are the better choice when your soil is alkaline or heavy, or when you only have a deck or patio. Potted bushes stay smaller and need more attention to water and winter protection.
In the ground, dormant half-high blueberries are rated to zone 3 (about -30°F to -40°F) and northern highbush to zone 4 (about -20°F to -30°F). Roots in a pot freeze far more easily, which is why a potted plant needs to be rated one to two zones colder than where you live. In spring, flower buds that have started to open can be damaged at around 20°F.
Check out this collection of over 80 blueberry recipes, developed and tested from our farm (Heathglen Farm). Available in pdf form as a digital ebook ($14.95), or as a print book from Amazon (paperback or hardcover).
Please I have a question about blueberries plants.
I have four blueberries plants,they are in pots,in winter I bury them, I would like to know what kind of fertilizer can I use , I used Espoma Organic Soil Acidifier for 3 years but one plant changed the fruit color , they are white blueberries I don’t know why , now I bought berry tone fertilizer it’s okay to use that? thanks
Hi Ruby, I have never heard of blueberries turning white before? It sounds like you may be overfertilizing rather than the wrong kind of fertilizer. Basically any fertilizer for acid plants like Azeleas etc. should work fine. I don’t use a lot of fertilizer on my plants, but I do use a lot of compost. I would try repotting them with a hefty amount of compost and then letting them rest without too much fertilizer for a while. They will usually tell you they need some food as their leaves start to turn yellow.
Ruby, I’m sorry, I missed your question about Berry-Tone. Yes, it’s made for acid-loving berries like blueberries and is safe to use; feed in early spring and follow the label. On the white berries, one possibility is mummy berry, a fungal disease that turns berries cream to gray and hard. If you see it again, pick off the affected berries and clear any fallen ones from the pot in fall.