Introduction
There is nothing quite like the tropical flair that cannas bring to a summer garden. With their oversized, banana-like leaves and brilliant blooms in shades of scarlet, orange, and gold, they turn any backyard into a lush retreat. The best part about growing these stunning plants is that they are not just a one-season wonder. Even if you live in a region with chilly winters, you can keep your cannas year after year.
Learning how to care for canna bulbs over winter is one of the most rewarding skills a gardener can develop. It is a simple process that saves money and allows you to grow your plant collection over time, as these rhizomes naturally multiply in the soil. At Longfield Gardens, we enjoy helping gardeners sustain their favorite plants across the seasons, ensuring that the vibrant colors of summer return even stronger next year.
This guide will walk you through the easy steps of digging, cleaning, and storing your cannas so they stay healthy until spring. Whether you are a beginner or an experienced gardener, you will find that learning how to store cannas for the winter is a straightforward way to protect your investment and enjoy a more beautiful garden. With just a little bit of preparation in the fall, your cannas will be ready to make a grand re-entrance once the weather warms.
Why Overwintering Cannas is a Smart Choice
Cannas are tropical and subtropical plants by nature. In warmer climates, specifically USDA hardiness zones 8 through 10, they can often stay in the ground year-round with just a thick layer of mulch for protection. However, in colder regions, the freezing temperatures of winter can damage the fleshy rhizomes if they are left in the soil.
Think of overwintering as a "winter nap" for your plants. By bringing them indoors, you are shielding them from the harsh elements that they aren't built to survive. It is a very sustainable way to garden. Instead of buying new plants every spring, you can reuse the ones you already have. Because cannas grow and expand during the summer, you will often find that you have twice as many plants to work with by the time you dig them up in the fall.
The process is also a great way to guarantee the quality of your garden. When you store your own rhizomes, you know exactly what variety you have and how healthy they were during the growing season. It gives you a head start on the next year’s landscape design, as you can plan exactly where your favorite tall orange cannas or variegated leaf varieties will go.
Can I Leave My Cannas in the Ground?
For those in USDA hardiness zone 7 microclimates, the decision to dig can be a tough call. In protected spots—such as a south-facing bed against a warm house foundation—cannas may survive if covered with 6 to 8 inches of straw or shredded leaves. However, if your soil is heavy clay or stays wet during the winter, the rhizomes will likely rot before spring. For most gardeners in Zone 7 and anywhere further north, we recommend digging them up to be safe. It is the only way to guarantee your favorite varieties return.
Timing Your Fall Harvest
Success starts with knowing the right time to act. If you dig too early, the rhizomes may not have stored enough energy for their dormant period. If you wait too long, a deep freeze might reach the roots and cause them to soften or rot.
The ideal signal to start the process is the first frost of autumn. You will notice the large, lush leaves of your cannas turn black or dark brown almost overnight after a light frost. While this might look a bit sad at first, it is actually a helpful sign from nature. The frost tells the plant that it is time to stop growing and move its energy down into the rhizome.
Wait until the foliage has been hit by a light frost but before the ground itself freezes solid. In most northern regions, this happens sometime between late September and early November. If you live in a place where frosts are rare or late, you can simply wait until the foliage begins to naturally yellow and die back as the days get shorter and temperatures drop into the 40s.
Key Takeaway: The best time to dig your canna rhizomes is right after the first light frost has blackened the leaves. This ensures the plant has finished its growth cycle and is ready for dormancy.
Preparing the Plants for Digging
Before you reach for your shovel, you need to clear away the top growth. Trying to dig up a five-foot-tall plant with all its leaves attached is difficult and unnecessary.
Start by cutting the stalks down to about two to three inches above the soil line. You can use a pair of sharp garden shears or a lopper for this. This short "handle" of the remaining stalk is useful for identifying the center of the plant and gives you something to hold onto, but it isn't so long that it gets in the way of your storage containers.
Once the foliage is removed, clear away any mulch or debris around the base of the plant. This makes it easier to see where the rhizomes are located. Canna rhizomes grow horizontally and can spread out quite a bit during a single summer, so clearing the area helps you avoid accidentally slicing through them with your spade.
Essential Tools for the Job
You don't need fancy equipment to dig up cannas, but having the right basic tools makes the work go faster:
- A garden fork or spade: A garden fork is often preferred because it is less likely to slice a rhizome in half than a flat shovel.
- Garden gloves: To protect your hands and provide a better grip.
- A garden hose: For a light rinse of the rhizomes.
- Labeling materials: Waterproof markers and tags are vital if you are growing several different varieties.
How to Dig Canna Rhizomes Safely
The goal is to lift the entire clump out of the ground with as little damage as possible. Because canna rhizomes are fleshy and full of water, they can be somewhat fragile.
Start by placing your garden fork about 8 to 12 inches away from the main stalk. Push the fork deep into the soil and gently rock it back and forth to loosen the earth. Move around the plant in a circle, loosening the soil from all sides. This "circles the wagons" approach ensures that you aren't prying against a stuck root that might snap.
Once the soil is loose all the way around, gently lift the entire clump upward. You may need to use your hands to help clear away large chunks of soil as you lift. If the clump is very large and heavy, don't worry about keeping it in one piece. It is natural for the rhizomes to start separating at this stage.
As you lift the plants out, take a moment to admire the growth. A single rhizome planted in May can often turn into a cluster of five or six by October. This is the "magic" of cannas—they are incredibly productive plants that reward your care with abundance.
Cleaning and Sorting
Once the rhizomes are out of the ground, they will likely be covered in damp soil. It is important to remove the bulk of this dirt, as soil can hold onto moisture and pathogens that might lead to rot during the winter.
Gently shake the clumps to knock off the loose earth. You can also use your fingers to brush away soil from the crevices between the rhizomes. Some gardeners prefer to use a garden hose to wash the rhizomes clean. If you choose to rinse them, use a gentle spray. Avoid high-pressure nozzles that could tear the "skin" of the rhizome.
While cleaning, perform a quick health check. Look for any rhizomes that feel mushy, look heavily bruised, or show signs of insect damage. It is better to compost these damaged pieces now rather than store them with your healthy ones. A healthy canna rhizome should feel firm, similar to a fresh potato or a piece of ginger root.
To Divide or Not to Divide?
You have two choices at this stage: you can store the clumps whole, or you can divide them into smaller pieces.
- Storing Whole: This is the easiest method and takes the least amount of time. It also helps the rhizomes retain moisture more effectively.
- Dividing Now: If you have limited storage space, you might want to divide them into individual sections now. Each section must have at least one or two "eyes" (the small bumps where new growth will emerge). If you divide them now, it is a good idea to let the cut ends dry thoroughly for an extra day or two to prevent infection.
Most gardeners find it simpler to store the clumps whole and wait until spring to do any major dividing. This gives you more flexibility when you are ready to replant.
The Importance of Curing
Curing is perhaps the most overlooked step in the overwintering process, but it is one of the most important. Curing is the process of letting the outer surface of the rhizomes dry and toughen up before they go into long-term storage.
After cleaning your cannas, move them to a dry area with excellent airflow. Ideally, you want a 70–80°F curing temperature to speed up the process. Spread them out in a single layer on a piece of cardboard, newspaper, or a mesh screen. Do not stack them on top of each other, as they need good circulation to dry properly.
Let the rhizomes cure for about 3 to 7 days. During this time, the outer skin will become slightly firmer. This process is called callusing, where any cut surfaces or nicks seal over with a dry, protective "scab." This callusing acts as a natural barrier against rot and moisture loss during the winter months. If the weather is particularly damp or humid, you may want to use a small fan to keep the air moving around them.
What to do next:
- Cut stalks to 2-3 inches.
- Lift the clumps gently with a garden fork.
- Shake or rinse away excess soil.
- Allow rhizomes to air-dry (cure and callus) in a warm, protected spot for several days.
Choosing Your Storage Medium
You cannot simply toss canna rhizomes into a plastic bin and expect them to thrive. They need an environment that stays slightly moist—but never wet—and allows for a tiny bit of air exchange. The "medium" you pack them in is what maintains this balance.
When deciding how to store canna bulbs, your choice of material should depend on your specific storage environment:
Peat Moss or Coco Coir
This is the gold standard for many, especially if your storage area is naturally dry, such as a heated basement. Peat moss and coco coir are excellent at holding just a hint of moisture to prevent the rhizomes from shriveling, while still being loose and airy. They are also naturally slightly acidic, which can help discourage certain types of fungal growth.
Wood Shavings or Sawdust
Pine or cedar shavings (the kind sold for pet bedding) are very popular for storage spaces that are naturally damp or humid, like a cool garage or crawl space. They provide excellent insulation and allow for superior airflow, which helps prevent moisture from being trapped against the plant.
Vermiculite or Perlite
These lightweight minerals are great for absorbing excess moisture. If you live in a very humid climate, packing your cannas in vermiculite can help prevent the rhizomes from getting too damp and rotting.
Newspaper or Brown Paper Bags
For those who prefer a simpler approach, wrapping individual rhizomes in several layers of dry newspaper works surprisingly well. You can then tuck the wrapped bundles into a cardboard box. This method is very clean and makes it easy to check on individual plants during the winter.
Packing Your Cannas for the Season
Once your rhizomes are cured and you have chosen your packing material based on your local humidity, it is time for the final move. The container you choose should be breathable. Cardboard boxes, paper grocery bags, or plastic bins with holes drilled in the sides are all great choices. Avoid airtight plastic tubs, as these trap moisture and almost always lead to rot.
Start by placing a two-inch layer of your chosen medium at the bottom of the container. Place a layer of rhizomes on top, making sure they aren't touching each other. This is important; if one rhizome starts to rot, you don't want it to spread to its neighbors.
Cover the first layer with more packing material and repeat the process until the container is full. Finish with a thick layer of medium on top to keep the light out and provide insulation.
Don't Forget the Labels!
It is incredibly easy to forget which box contains the 'Red King Humbert' and which one has the City of Portland by the time March rolls around. Write the variety name and the flower color on a tag or directly on the outside of the box. If you have several different heights of cannas, it is also helpful to note how tall they grow so you can plan your spring garden beds easily.
Finding the Perfect Storage Location
The location where you keep your boxes is just as important as how you pack them. Cannas need a spot that is "cool but not cold."
The ideal temperature range for canna rhizome winter storage is between 40°F and 50°F (4°C to 10°C). If the temperature stays above 60°F, the rhizomes might think it is spring and try to start growing prematurely. If the temperature drops below freezing, the water inside the rhizomes will turn to ice, expanding and destroying the plant's cell structure.
Common successful storage spots include:
- An unheated basement: This is usually the best option as the temperature stays very stable.
- A crawl space: Often stays within the perfect temperature range.
- An insulated garage: Just make sure the boxes aren't sitting directly on a cold concrete floor; place them on a shelf or a piece of wooden pallet.
- A cool closet: In a house that is kept relatively cool, an interior closet might work if it's away from heating vents.
Winter Maintenance and Troubleshooting
Overwintering is not a "set it and forget it" task. To ensure a high survival rate, you should check on your boxes about once a month. This small effort can save your entire collection if something goes wrong. Ideally, you are aiming for the environment within the packing medium to hover around 40–50% humidity.
Troubleshooting Common Storage Issues
When you check your boxes, look for these common signs of trouble:
- Rot and Mold: If you find a rhizome that feels soft or mushy, remove it immediately. If you notice a light dusting of white mold, wipe it off with a cloth dipped in a 10% bleach solution or a mild fungicide, and increase the airflow in your storage container.
- Shriveling: If the rhizomes feel very light and look wrinkled like a prune, they are getting too dry. To fix this, use a spray bottle to lightly mist the packing medium. You don't want to make it wet; just a tiny bit of dampness will help the rhizomes rehydrate.
- Early Sprouting: If you see green tips emerging in January or February, your storage location is too warm. Move the boxes to a cooler spot (closer to 40°F) to slow down their metabolism and keep them dormant until spring.
Natural Attrition
Don't be discouraged if you lose a few rhizomes over the winter. Even professional growers expect a small percentage of loss. If you find that 80% to 90% of your cannas survive until spring, you are doing a fantastic job. Every year you do this, you will learn more about the specific microclimate of your storage area and can adjust your methods accordingly.
Special Care for Potted Cannas
If you grow your cannas in large decorative pots, you have a bit of a shortcut. You don't necessarily have to dig them up at all.
Once the first frost has hit the plants, cut the foliage down to the soil line just as you would with garden-planted cannas. Instead of digging them out, you can simply move the entire pot into a frost-free area like a basement or garage. For city gardeners or those with limited outdoor space, Short Cannas are another good choice.
The soil in the pot acts as the "packing medium." You should stop watering the pots entirely once you move them indoors. The soil should remain dry throughout the winter. In the spring, you can bring the pots back out, refresh the top few inches of soil with some fresh compost, and start watering again to wake them up. This is a very convenient option for city gardeners or those with limited outdoor space.
Waking Them Up in Spring
As the days begin to lengthen and the ground starts to thaw, it is time to think about the return of your tropical beauties. You can start this process about 4 to 6 weeks before your area's last expected frost date.
Take the rhizomes out of their storage boxes and inspect them one last time. While some gardeners divide in the fall, spring is the best time for most of us to do this work because the "eyes" (growth buds) are much easier to see.
Rules for Dividing in Spring
Use a clean, sharp knife to cut the rhizomes into sections. For the best results and most vigorous growth, aim for 3–5 eyes per division. These eyes look like small, swollen bumps or points, often pink or white in color. While a single eye will grow, a larger division with 3–5 eyes will produce a much fuller, multi-stemmed plant during its first season back in the garden.
Potting Up Early
If you want your cannas to bloom earlier in the summer, you can "start" them indoors. Plant the rhizomes in pots filled with moist potting soil and place them in a warm, sunny window or under grow lights. This gives them a head start so that by the time it is warm enough to plant them outside, they already have several inches of green growth.
Planting Directly in the Garden
If you prefer to wait, you can plant the rhizomes directly into the garden once the soil has warmed up to at least 60°F and there is no longer any danger of frost. Plant them about 4 inches deep with the eyes pointing upward. For more planting depth guidance, see How Deep to Plant Canna Lily Bulbs. Because we provide high-quality plants at Longfield Gardens, we know how exciting it is to see those first green spears poke through the soil. The patience of winter truly pays off when those vibrant leaves begin to unfurl.
Safety for Pets and Children
When gardening with cannas, it is always helpful to know about the safety of the plants in your yard. One of the many reasons gardeners love cannas is that they are generally considered non-toxic to dogs, cats, and horses. Unlike many other summer bulbs like lilies or dahlias, cannas are safe to have around curious pets.
However, as a general rule, it is always best to keep any stored bulbs or rhizomes out of reach of children and animals. While they aren't toxic, they aren't meant to be eaten, and the packing materials like vermiculite or peat moss should not be ingested. Keeping your storage boxes tucked away in a safe, high spot or a closed closet is the best practice for a happy, healthy home.
Final Checklist for Spring Success:
- Inspect rhizomes for firmness in late winter.
- Divide clumps into pieces with at least 3–5 "eyes."
- Optionally pot up indoors 4-6 weeks before the last frost.
- Wait for warm soil (60°F) before planting outdoors.
Conclusion
Storing canna bulbs over winter is a simple, fulfilling cycle that connects you more deeply to the rhythm of the seasons. By taking just an hour or two on a crisp autumn afternoon to lift and pack away these tropical treasures, you ensure that your garden will be filled with spectacular color and lush foliage next summer. It is a practical way to grow your garden’s beauty while enjoying the satisfaction of preserving the plants you love.
We hope this guide makes the process feel easy and achievable. Gardening is a journey of discovery, and every year you successfully overwinter your cannas, you become a more confident and skilled grower. At Longfield Gardens, we are always here to support your gardening adventures with quality plants and straightforward advice.
If you need a mid-size option, browse our Medium Cannas.
As the winter snow falls, you can rest easy knowing your cannas are tucked away, ready to bring that tropical magic back to your yard once the sun returns.
Overwintering cannas is the best way to expand your garden for free while keeping your favorite varieties safe. With a cool, dry spot and a bit of patience, you can enjoy these tropical giants year after year.
FAQ
When is it too late to dig up my canna rhizomes?
You should aim to dig them up before the ground freezes solid. While a light surface frost will kill the leaves and is actually helpful, a "hard freeze" that penetrates several inches into the soil can damage the rhizome. If you've had a few nights of freezing temperatures, check the soil; if it's still workable and soft, you can usually still save the rhizomes.
Can I store cannas in my unheated garage?
An unheated garage is a great choice as long as it stays above freezing (32°F). If your garage is not insulated and temperatures inside drop significantly below freezing, the rhizomes will likely be damaged. A good tip is to keep the boxes on an interior wall or inside a secondary insulated container if you're worried about extreme cold snaps.
What should I do if my stored cannas look very shriveled in February?
Shriveling is a sign that the environment is too dry. Take a spray bottle filled with water and lightly mist the packing medium (the peat moss or wood shavings). You don't want to soak the rhizomes, just introduce a tiny bit of humidity back into the box. They should firm up slightly over the next few weeks.
Do I really need to wash all the dirt off before storing them?
While you don't need to make them perfectly clean, removing the majority of the soil is highly recommended. Soil holds moisture, and damp soil pressed against the rhizome for months can lead to fungal issues or rot. Shaking them well and giving them a light brush or rinse ensures they stay dry and healthy throughout their dormancy.
