Table of Contents
- Introduction
- Understanding Canna Hardiness: The Zone Rule
- Leaving Cannas in the Ground: Best Practices for Warm Climates
- Why Some Gardeners Choose to Lift Cannas Anyway
- Step-by-Step: How to Lift and Store Canna Rhizomes
- Finding the Perfect Storage Location
- Winter Care for Cannas in Containers
- Mid-Winter Checkups: What to Look For
- Realistic Expectations for Winter Survival
- Preparing for a New Season: Moving from Storage to Soil
- Summary of Winter Canna Care
- Conclusion
- FAQ
Introduction
Few plants bring the same level of tropical excitement to a backyard as the canna lily. With their towering heights, lush foliage that looks like it belongs in a rainforest, and vibrant blooms in shades of sunset orange, fiery red, and sunny yellow, they are a highlight of the summer garden. We love how cannas can transform a standard patio or flower bed into a vacation-like retreat with very little effort during the growing season. At Longfield Gardens, we want to help you keep that tropical beauty coming back year after year.
One of the most common questions we hear as the days grow shorter is whether these spectacular plants can stay in the garden during the cold months. The answer depends almost entirely on where you live and how you prepare your soil. For some, winter care is as simple as adding a layer of mulch, while for others, it involves a rewarding afternoon of "lifting" and storing rhizomes for a fresh start in the spring. For a broader overview, see All About Cannas.
This guide will help you determine the best winter strategy for your specific climate. We will walk through how to identify your USDA Plant Hardiness Zone, how to protect cannas that stay in the ground, and the easiest way to store them indoors if your winters are a bit too chilly for these tropical favorites. By the end, you will have a clear plan to ensure your cannas return even bigger and better next season.
Cannas are remarkably resilient when they are given the right winter conditions. Whether you are a busy gardener looking for the simplest approach or an enthusiast ready to build a massive collection of varieties like Tropicanna or 'Black Knight', understanding winter care is the key to long-term success.
Understanding Canna Hardiness: The Zone Rule
Before you decide whether to leave your canna rhizomes in the earth, you need to know your USDA Plant Hardiness Zone. These zones are based on the average minimum winter temperature in your area. Because cannas are tropical and subtropical plants, they have a specific limit for how much cold they can handle.
In the gardening world, we often refer to the underground part of the canna as a "bulb," but it is technically a rhizome. A rhizome is a thick, fleshy underground stem that stores energy for the plant. Because these rhizomes are full of water, they are sensitive to freezing. If the ground freezes solid where the rhizome is sitting, the water inside the plant tissue expands and damages the cells, which usually leads to the plant rotting away.
Zones 7 to 11: The "Stay in the Ground" Zones
If you live in USDA zones 8, 9, 10, or 11, you can almost always leave your canna rhizomes in the ground year-round. In these regions, the soil rarely freezes deep enough to reach the rhizomes. In Zone 7, leaving them in the ground is usually successful, though it can depend on the specific winter. If you have a particularly cold year or live in the northern part of Zone 7, a little extra protection goes a long way.
Zone 6 and Colder: The "Lift and Store" Zones
For gardeners in Zone 6, 5, 4, and lower, the ground freezes deep and stays frozen for long periods. In these areas, cannas left in the ground will not survive the winter. However, this shouldn't discourage you from growing them! Lifting and storing cannas is a straightforward process that many gardeners find very rewarding. It is a simple way to protect your investment and ensure you don't have to buy new plants every spring.
Key Takeaway: The "safe" zone for leaving cannas in the ground is Zone 8 and warmer. Zone 7 is often safe with mulch, but Zone 6 and colder requires digging the rhizomes up to keep them from freezing.
Leaving Cannas in the Ground: Best Practices for Warm Climates
If you are lucky enough to live in a climate where cannas can stay outdoors, your "winter chore" is mostly about tidying up and providing a cozy blanket for the soil. Even in warm areas, cannas go through a period of dormancy, which means they stop growing and rest until the warmth returns.
Timing the Cut-Back
In late autumn, after the first light frost or once the leaves naturally start to turn yellow or brown, it is time to cut the plants back. The frost will often turn the lush green leaves to a dark, toasted color. This is perfectly normal and actually signals to the plant that it is time to sleep.
Use a clean pair of garden shears to cut the stems down. Most gardeners find that leaving about 4 to 6 inches of stem above the soil line is ideal. This marks the spot where the plants are located so you don't accidentally dig into them later, and it provides a bit of a handle if you ever decide to divide them.
The Importance of Mulch
In Zone 7 and 8, mulch is your best friend. Even if the air temperature drops below freezing, a thick layer of organic material acts like insulation for the soil. It keeps the ground temperature more stable and prevents the frost from reaching the rhizomes.
Apply a 4-to-6-inch layer of straw, shredded leaves, or wood chips over the area where the cannas are planted. This "blanket" will protect the plants through the coldest nights of January and February. In very warm zones like 10 or 11, mulch is less about cold protection and more about keeping the soil moisture consistent and preventing weeds.
Managing Winter Drainage
One of the most important factors for leaving cannas in the ground is drainage. Drainage simply means how fast water leaves the soil. While cannas love lots of water during the hot summer months, they do not like to sit in cold, soggy soil during the winter.
If your garden has heavy clay soil that stays wet and "mucky" all winter, the rhizomes may rot even if it doesn't freeze. If you know your soil holds a lot of water, you might consider digging the rhizomes up regardless of your zone, or planting them in raised beds where water can drain away more easily.
Why Some Gardeners Choose to Lift Cannas Anyway
Even in warmer zones where cannas could survive the winter, some gardeners choose to dig them up every few years. This is because cannas are vigorous growers. A single rhizome planted in the spring can turn into a large, crowded clump by the end of the season.
When the clump gets too big, the plants can become crowded. Crowded plants often produce smaller flowers and may not grow as tall as they used to. Lifting the rhizomes allows you to divide the large clumps into smaller pieces. You can then replant the best pieces in the spring, give some away to neighbors, or expand your canna display to other parts of the yard.
What to do next:
- Identify your USDA hardiness zone using a local map or zip code search.
- If you are in Zone 8 or higher, plan to buy mulch in late fall.
- If you are in Zone 6 or lower, set aside a weekend after the first frost for "lifting" your plants.
Step-by-Step: How to Lift and Store Canna Rhizomes
If you live in a cold climate, lifting your cannas is the best way to ensure they return. Think of it as putting your plants into a safe, climate-controlled "hotel" for the winter. The process is easy and can be done with basic garden tools.
Step 1: Wait for the Frost
The best time to dig up cannas is right after the first "blackening" frost. This is when the temperature drops enough to kill the foliage but hasn't yet frozen the ground. The frost tells the plant to move all its energy down into the rhizome. Once the leaves look wilted and dark, you are ready to begin.
Step 2: Cut Back the Foliage
Just like in warm climates, start by cutting the stems back. Use your shears to cut the stalks down to about 4 inches. Removing the bulky leaves makes it much easier to see what you are doing and handle the roots.
Step 3: Dig Carefully
You want to avoid "nicking" or cutting the rhizomes with your shovel. A garden fork is often better for this job than a pointed spade. Start digging about 12 inches away from the base of the stems. Gently loosen the soil all the way around the plant, then use the fork to pry the entire clump out of the ground.
Step 4: Clean and Inspect
Gently shake the clump to remove large chunks of soil. You don't need to wash them with a hose—in fact, keeping them dry is better for storage. Use your hands to brush away excess dirt. Inspect the rhizomes for any soft spots or signs of damage. Healthy rhizomes should feel firm, similar to a potato or a fresh piece of ginger.
Step 5: The "Curing" Process
Curing is a fancy word for letting the rhizomes dry out slightly before they go into storage. Place the clumps in a dry, frost-free area like a garage or a shed for 2 to 3 days. This allows the outer "skin" to toughen up, which helps prevent rot and keeps the moisture inside the rhizome where it belongs.
Step 6: Proper Storage Containers
Once cured, place the rhizomes in a container that allows for some air circulation. Plastic bins with holes, cardboard boxes, or even paper bags work well. Most gardeners find success by "nesting" the rhizomes in a packing medium.
Good options for storage media include:
- Peat moss: Holds just the right amount of moisture.
- Vermiculite or Perlite: Provides great aeration.
- Shredded newspaper: A simple, cost-effective option.
- Wood shavings: Often sold as animal bedding.
The goal is to keep the rhizomes from touching each other directly. If one develops a spot of rot, the packing medium helps prevent it from spreading to the others.
Finding the Perfect Storage Location
The location where you keep your stored cannas is just as important as how you pack them. You are looking for a "Goldilocks" spot: not too hot, not too cold.
The ideal temperature for storing canna rhizomes is between 40°F and 50°F. If the area is too warm (like a heated living room), the rhizomes might think it is spring and start to grow prematurely, or they may dry out too much. If the area is too cold (like an uninsulated shed in Minnesota), they will freeze and die.
Common successful storage spots include:
- Unheated basements: These usually stay cool and dark.
- Crawl spaces: Often have stable, cool temperatures.
- Attached garages: As long as they don't drop below freezing.
- Root cellars: The traditional choice for storing bulbs and tubers.
Key Takeaway: Successful storage depends on "curing" the rhizomes for a few days and then keeping them in a cool (40–50°F), dark place nestled in a dry medium like peat moss.
Winter Care for Cannas in Containers
Growing cannas in pots is a popular choice, especially for the stunning 'Orange Punch' or other dwarf varieties. Short Cannas are a great choice for winter care because they are mobile.
For Warm Zones (Zones 8-11)
If you grow cannas in pots in a warm climate, you can simply leave them outside. However, remember that soil in a pot can get colder than soil in the ground because it is surrounded by air. If a surprise freeze is predicted, move your pots against the side of the house or wrap them in burlap for a night or two. If you want more guidance on container planting, see How to Plant Canna Lily Bulbs in Pots.
For Cold Zones (Zone 7 and Colder)
The easiest way to overwinter container-grown cannas is to bring the entire pot inside. Once the foliage has been hit by frost, cut it back to the soil level. Then, move the pot into a cool basement or garage. You don't even need to dig the rhizomes out of the dirt!
Stop watering the pot entirely. The soil will dry out, and the canna will go into a deep sleep. In the spring, when the weather warms up, you can move the pot back outside, give it a good soak, and wait for the new sprouts to appear. This is often the most "hassle-free" way to enjoy cannas in cold climates.
Mid-Winter Checkups: What to Look For
It is a good idea to check on your stored canna rhizomes once or twice during the winter. This takes only a few minutes but can save your entire collection.
Open your storage boxes and feel a few of the rhizomes.
- If they feel shriveled or very dry: They might be losing too much moisture. Use a spray bottle to lightly mist the packing medium (not the rhizomes themselves) with a little water. You want the medium to feel barely damp, not wet.
- If they feel soft or mushy: This is a sign of rot. Remove any mushy rhizomes immediately so the rot doesn't spread. If only a small part of a rhizome is soft, you can sometimes cut that part off with a clean knife and let the healthy part dry out again.
Checking them in January and March is usually enough to ensure they stay healthy until planting time.
Realistic Expectations for Winter Survival
While we always aim for 100% success, it is important to remember that gardening involves living things and unpredictable weather. Even with the best care, a few rhizomes might not make it through the winter. This is why many gardeners store a few extra "backups."
Factors that can affect winter survival include:
- The health of the plant during summer: A plant that was well-fed and watered all summer will have more energy stored in its rhizome for the winter.
- Humidity levels in storage: Very dry air can cause shriveling, while very humid air can encourage mold.
- Soil moisture at the time of lifting: If you dig your cannas up during a very rainy week, they may need an extra day or two of curing to ensure they aren't too wet when they go into boxes.
Don't be discouraged if a few rhizomes don't sprout in the spring. It is all part of the learning process. The vast majority of the time, your cannas will reward your efforts with spectacular growth as soon as the ground warms up.
Preparing for a New Season: Moving from Storage to Soil
As the days begin to lengthen in late March or April, you will start thinking about getting your cannas back into the garden. If you're ordering new rhizomes, our Shipping Information page explains timing by zone. The most important rule for spring is to wait for the warmth.
Cannas are true sun-lovers. They do not like cold soil. A good rule of thumb is to wait until the soil temperature is at least 60°F before planting them outside. This is usually around the same time you would plant tomato seedlings or peppers in your garden.
Starting Indoors
If you want to get a "jump start" on the season, you can take your rhizomes out of storage about 4 to 6 weeks before the last frost date. For a step-by-step head start, see Starting Canna Lily Bulbs Indoors. Plant them in pots with some moist potting soil and keep them in a warm, sunny window or under grow lights. By the time the weather is warm enough to move them outside, you will already have several inches of lush green growth. This is a great way to ensure a longer blooming season, especially in northern states where the summer is short.
Dividing the Clumps
Before you replant, look at your rhizomes. If you have large clumps, you can easily break or cut them into smaller pieces. Each piece should have at least one or two "eyes." These eyes look like small, pointed bumps or buds on the surface of the rhizome. Each eye will grow into a new stalk.
When you replant, place the rhizomes horizontally in the soil, about 2 to 4 inches deep. Space them about 1 to 2 feet apart to give them plenty of room to show off their massive leaves.
Summary of Winter Canna Care
Managing your cannas through the winter is one of the most rewarding parts of the gardening cycle. It connects the end of one beautiful season to the promise of the next. Whether you choose to leave them in the ground under a thick layer of mulch or store them safely in your basement, the goal is the same: protecting the energy stored in those fleshy rhizomes.
At Longfield Gardens, we believe that gardening should be a joy, not a source of stress. Overwintering cannas is a straightforward task that quickly becomes a simple habit. By matching your care to your local weather, you can enjoy these tropical showstoppers for many years to come.
Final Action Plan:
- Check your zone: 8+ stays in the ground, 7 is a choice, 6 and below comes inside.
- Time it right: Wait for the first frost before cutting back or lifting.
- Store cool and dry: 40–50°F in a breathable container with peat moss.
- Wait for warmth: Only replant when the soil is warm and the danger of frost has passed.
"Canna lilies are the ultimate 'return on investment' plant. A little bit of care in the fall leads to a massive tropical explosion in the summer."
Conclusion
Whether you are looking to create a backyard oasis or just want a few bold focal points in your flower beds, cannas are a fantastic choice. Leaving them in the ground is a great "easy win" for those in southern climates, while lifting and storing them is a simple, effective tradition for northern gardeners. By following these basic steps, you can ensure your garden remains vibrant and tropical year after year. We are here to support your journey with high-quality rhizomes and the practical advice you need to grow them with confidence. Ready to plan next year's colors? Explore our assorted cannas collection and get ready for another season of spectacular blooms.
FAQ
Can I leave my cannas in the ground if I live in Zone 7?
Yes, you can often leave cannas in the ground in Zone 7, but it is considered a "borderline" area. To ensure they survive, apply a very thick layer of mulch (at least 6 inches) over the planting site after you cut the stems back in the fall. This insulation helps protect the rhizomes from occasional deep freezes.
What happens if I don't dig up my cannas in a cold climate?
If you live in a cold climate like Zone 5 or 6 and leave your cannas in the ground without protection, the rhizomes will most likely freeze and turn to mush. Once the cell walls are destroyed by freezing, the rhizome will rot when the soil thaws in the spring, and the plant will not regrow.
Do I need to water my canna rhizomes while they are in storage?
Generally, no. You want the rhizomes to remain dormant and dry. However, if you check them in mid-winter and they feel extremely shriveled or brittle, you can lightly mist the storage medium (like peat moss) with a spray bottle. Avoid making the rhizomes wet, as this can lead to rot.
When is the best time to replant stored canna rhizomes in the spring?
Wait until the soil has warmed up to at least 60°F and there is no more danger of frost. In most regions, this is the same time you would plant other warm-weather favorites like zinnias or tomatoes. Planting too early in cold, wet soil can cause the rhizomes to rot before they have a chance to grow.