Table of Contents
- Introduction
- Understanding Canna Rhizomes
- When to Start Winter Storage for Canna Bulbs
- How to Dig Canna Rhizomes Safely
- Cleaning and Preparing for Storage
- The Importance of Curing
- Choosing Your Storage Medium
- Packing Your Cannas for the Winter
- Finding the Perfect Storage Location
- Monitoring Your Cannas During Winter
- Storing Cannas Grown in Containers
- Dividing Cannas: Fall or Spring?
- Preparing for Spring Replanting
- Conclusion
- FAQ
Introduction
There is nothing quite like the tropical flair that cannas bring to a summer garden. Their oversized, paddle-shaped leaves and vibrant, jewel-toned flowers create a lush sanctuary in any backyard. At Longfield Gardens, we love how these fast-growing cannas transform a landscape into a private getaway. The only challenge for many gardeners is that cannas are tropical natives that prefer warm weather year-round.
If you live in a region where the ground freezes, you will need to plan for winter storage for canna bulbs to keep them safe until spring. Fortunately, saving these plants is a straightforward and rewarding process; How to Dig Up and Store Canna Lily Bulbs walks through the same steps. This guide will walk you through the simple steps of digging, curing, and storing your canna rhizomes so they stay healthy through the coldest months.
By following a few basic principles, you can easily preserve your garden investment and enjoy these stunning blooms for many seasons to come.
Understanding Canna Rhizomes
Before we dive into the storage process, it is helpful to know exactly what you are working with. All About Cannas is a useful overview of canna rhizomes and how they grow.
In their native tropical environments, cannas grow continuously. However, in most of the United States, they enter a dormant state when the temperatures drop. This dormancy is the key to successful winter storage. When you dig them up and keep them in a cool, dark place, you are essentially hitting the "pause" button on their growth cycle.
It is important to remember that these rhizomes are full of water. This high moisture content makes them very sensitive to freezing temperatures. If the water inside the rhizome freezes, the cells rupture, and the plant will not survive. This is why timing your winter storage for canna bulbs is the most important part of the process.
When to Start Winter Storage for Canna Bulbs
Timing is everything when it comes to garden success. For cannas, the best time to start the overwintering process is right after the first light frost of the autumn. If you want to check your timing by region, use the USDA hardiness zone map. You will know it has happened because the once-vibrant green or burgundy leaves will suddenly turn dark brown or black.
This might look like a sad moment for your garden, but it is actually a helpful signal from nature. This first touch of cold tells the plant to stop sending energy to its leaves and flowers. Instead, the plant moves its remaining sugars down into the rhizome. Waiting for this signal ensures the rhizome is as "fueled up" as possible for its long winter nap.
Watching the Weather
While you want to wait for that first light frost, you should not wait for the ground to freeze hard. A light frost only affects the foliage above the ground, but a deep freeze can penetrate the soil and damage the rhizomes.
In most areas, this timing falls between late September and early November, depending on your local climate. If you live in a region where frosts are rare or late, you can simply wait until the foliage starts to naturally yellow and die back as the days get shorter.
The Zone 7 and 8 Exception
If you live in USDA hardiness zones 8 through 10, your cannas may be able to stay in the ground all winter. For a dramatic border planting, browse Tall Cannas. Many gardeners in zone 7 also have success leaving their plants in the ground if they provide a thick layer of mulch—about 6 to 8 inches of straw or shredded leaves—to act as a warm blanket.
However, even in warmer zones, many people choose to dig up their cannas every few years. This allows them to divide the clumps and keep the plants from becoming too crowded. If you want to move your plants to a new location or share them with friends, the fall digging window is the perfect time to do it.
How to Dig Canna Rhizomes Safely
Once the frost has nipped the leaves, it is time to get your tools ready. You don't need fancy equipment for this job; a sturdy garden spade or a large garden fork will work perfectly. For a step-by-step walkthrough, see How to Remove Canna Lily Bulbs. The goal is to lift the entire clump of rhizomes without cutting into the fleshy parts.
Step 1: Cut Back the Foliage
Before you start digging, use a pair of clean garden shears to cut the stalks down. Aim for about 3 to 4 inches above the soil line. Leaving a small "handle" of the stem makes the rhizomes easier to manage and helps you keep track of which side is up. Removing the bulky leaves also makes it much easier to see where the base of the plant is.
Step 2: Clear the Perimeter
Cannas can grow quite large over a single summer. A single rhizome planted in May can turn into a massive clump by October. To avoid accidentally slicing through the rhizomes, start digging about 6 to 12 inches away from the base of the stems.
Push your spade or fork deep into the soil all the way around the plant. This loosens the earth and severs the smaller feeder roots that aren't necessary for winter storage.
Step 3: Lift the Clump
Once you have loosened the soil in a circle around the plant, gently pry upward. If the clump is large, you may need to lift from several different angles. Try to lift the entire mass of soil and rhizomes at once.
Once the clump is out of the ground, you can gently shake it or crumble away the large chunks of soil with your hands. Don't worry about getting them perfectly clean yet; the priority is simply getting them safely out of the earth.
Key Takeaway: Be Gentle with the Skin Canna rhizomes have a relatively thin skin when they first come out of the ground. Avoid using sharp tools to scrape away dirt, as any nicks or bruises can become entry points for rot during the winter. A gentle touch is all you need.
Cleaning and Preparing for Storage
With the rhizomes out of the ground, the next step is cleaning. There are two schools of thought on this: the "dry brush" method and the "rinse" method. Both work well, but your choice might depend on your soil type. While you are cleaning, take a moment to look at each rhizome and compare it with How to Tell if Canna Bulbs are Good.
The Dry Brush Method
If your soil is sandy or loose, you can often just let the clumps sit for an hour or two in the sun. The soil will dry out and fall away easily. You can use your gloved hands or a soft brush to remove the remaining dirt. This method is great because it keeps the rhizomes dry, which reduces the risk of fungal issues later.
The Rinse Method
If you have heavy clay soil, it often sticks to the rhizomes like glue. In this case, you can use a garden hose with a gentle spray to wash the soil away. If you choose to rinse your cannas, it is vital that you allow them to dry completely before moving to the next step. Wet rhizomes in a storage box are a recipe for mold.
Inspecting Your Harvest
While you are cleaning, take a moment to look at each rhizome. You want to store only the healthiest pieces. Look for rhizomes that feel firm and heavy for their size. If you find any parts that are mushy, shriveled, or showing signs of insect damage, trim those parts away or discard that particular piece. Healthy rhizomes are usually creamy white, tan, or pinkish on the inside.
The Importance of Curing
Curing is a step that many beginners skip, but it is a secret to long-term success. Curing is simply the process of letting the rhizomes air-dry in a protected spot for several days. This helps the outer skin toughen up and "set," which makes the rhizome much more resistant to rot and moisture loss during the winter. For a fuller seasonal overview, see How to Care for Canna Bulbs: A Complete Seasonal Guide.
To cure your cannas, spread them out in a single layer on a piece of cardboard, a tarp, or a wire rack. Choose a location that is dry and well-ventilated, such as a garage, a shed, or a covered porch. Ideally, the temperature should be between 60°F and 70°F during this time.
Let the rhizomes sit for about 4 to 7 days. By the end of the week, the remaining soil will be bone-dry, and the cut ends of the stems will have shriveled and calloused over. Once they feel dry to the touch and the skin looks a bit "corky," they are ready for their final winter home.
What to Do Next: Post-Curing Checklist
- Check that all cut stems are dry and firm.
- Remove any remaining loose soil that has dried.
- Label your varieties with a permanent marker directly on the rhizome or use a tag.
- Group similar sizes together to make spring planting easier.
Choosing Your Storage Medium
The goal of winter storage for canna bulbs is to keep them in a "Goldilocks" environment: not too wet (which causes rot) and not too dry (which causes them to shrivel up and die). To learn more about how long they can keep, see How Long Can You Store Canna Lily Bulbs? Storage Tips. To achieve this, we use a packing medium that regulates moisture.
There are several excellent options for packing your cannas:
Peat Moss or Coco Coir
This is perhaps the most popular choice. These materials are excellent at holding just a tiny bit of moisture while still allowing the rhizomes to breathe. You can buy bags of these at most garden centers. Use the material slightly damp—not wet. If you squeeze a handful, it should feel like a wrung-out sponge.
Vermiculite or Perlite
These are mineral-based options that are naturally sterile. They are very lightweight and do a great job of preventing the rhizomes from touching each other, which stops the spread of any potential rot.
Wood Shavings or Sawdust
If you have access to untreated wood shavings (like the kind used for animal bedding), these work very well. They are breathable and easy to handle. Avoid shavings from cedar or chemically treated wood, as these can sometimes inhibit growth.
Newspaper
For a low-cost option, you can simply wrap each individual rhizome in several layers of newspaper. The paper acts as a buffer, absorbing excess moisture while providing a bit of insulation.
Packing Your Cannas for the Winter
Now that you have your medium ready, it is time to pack the boxes. You can use cardboard boxes, plastic bins with the lids left cracked open, or even breathable mesh bags.
- Start with a Base Layer: Place about 2 to 3 inches of your chosen storage medium at the bottom of the container.
- Arrange the Rhizomes: Lay the rhizomes on top of the medium. Make sure they are not touching each other. This ensures that if one rhizome starts to decay, it won't immediately spoil its neighbors.
- Cover and Repeat: Add more medium until the first layer is completely covered. If your container is deep enough, you can add a second layer of rhizomes and cover them as well.
- Final Cover: Finish with a thick layer of the medium on top.
- Ventilation is Key: If you are using a plastic tote, do not snap the lid on tight. Rhizomes are living things and need a small amount of oxygen. Drill a few holes in the sides of the bin or leave the lid slightly ajar to allow for air circulation.
Finding the Perfect Storage Location
The location you choose for your stored cannas will determine whether they stay dormant or try to grow too early. You are looking for a spot that is cool, dark, and frost-free.
The ideal temperature range is between 40°F and 55°F. If the temperature stays in this range, the rhizomes will stay perfectly asleep. If it gets much warmer than 60°F, they may begin to sprout prematurely, wasting their stored energy. If the temperature drops below freezing, the rhizomes will likely be lost.
Best Storage Spots:
- Unheated Basements: Usually provide the perfect combination of coolness and humidity.
- Crawl Spaces: These often stay at a consistent, cool temperature throughout the winter.
- Attached Garages: These can work well, but be careful. If your garage isn't insulated, the temperature might drop too low during a cold snap. Keep the boxes on a shelf rather than directly on the cold concrete floor.
- Cool Closets: An interior closet that stays away from heating vents can work in a pinch.
Monitoring Your Cannas During Winter
Winter storage for canna bulbs isn't a "set it and forget it" task. You should plan to check on your rhizomes about once a month. This small effort can save your entire collection.
When you do your monthly check, look for two things: rot and shriveling.
Handling Rot
If you see any fuzzy mold or feel any soft, mushy spots on a rhizome, remove it immediately. If the damage is small, you can sometimes cut away the bad part and let the healthy part dry out. However, if the whole piece is soft, it is best to throw it away to protect the others.
Preventing Shriveling
If the rhizomes feel very light and look wrinkled like a raisin, they are losing too much moisture. To fix this, use a spray bottle to lightly mist the storage medium with water. You don't want to soak it—just add enough moisture to raise the humidity in the box.
Key Takeaway: The Firmness Test A healthy dormant canna rhizome should feel firm, similar to a fresh potato. If it feels like a sponge or a hollow shell, it needs attention. Regular check-ins ensure you catch these issues early.
Storing Cannas Grown in Containers
If you grow your cannas in large pots or decorative containers, you have a bit of a shortcut. If you want a compact option for pots, browse Short Cannas. You don't necessarily have to dig them out of the soil.
Once the frost hits, cut the foliage back to the soil level just as you would for in-ground plants. Move the entire container to a cool, dark, frost-free location like a basement or garage. Stop watering the pot entirely. The soil in the pot will act as the storage medium.
In the spring, you can bring the pot back into the light, start watering again, and the cannas will usually sprout right in place. However, keep in mind that cannas grow very quickly. After a year or two in the same pot, they will likely become "root-bound." At that point, you will need to tip the pot over, pull out the mass of rhizomes, and divide them to give the plants more room to grow.
Dividing Cannas: Fall or Spring?
As you dig up your cannas, you will notice that they have multiplied significantly. A single rhizome often turns into a large, heavy clump with many different "eyes" or growing points. If you prefer a mid-size planting next season, see Medium Cannas. You have the choice to divide these clumps either in the fall before storage or in the spring before planting.
Why Divide in the Fall?
Dividing in the fall makes the rhizomes easier to fit into storage boxes. It also allows the cut ends to callous over during the curing process, which can be very effective.
Why Divide in the Spring?
Many gardeners prefer to wait until spring. By then, it is very easy to see the small, swelling "eyes" where new growth will emerge. This makes it easier to ensure that every piece you plant has at least one or two healthy growing points.
Regardless of when you do it, use a sharp, clean knife. Each division should have at least one prominent bud (eye) and a good chunk of the fleshy rhizome to support its early growth.
Preparing for Spring Replanting
As winter winds down and the days begin to lengthen, you can start thinking about bringing your cannas out of storage. This usually happens about 4 to 6 weeks before the last expected frost date in your area.
You can give your cannas a "head start" by potting them up indoors in March or April. For a standout variety, try Canna Tall Tropicanna. Use a high-quality potting mix and place them in a warm, sunny window. This gives them a chance to develop roots and small shoots so that when you finally move them into the garden in late May or June, they are already well on their way to blooming.
Wait until the soil has warmed up to at least 60°F before planting them outside. Cannas love heat, so there is no rush to put them in cold, damp ground. They will grow much faster if you wait for the right conditions.
Conclusion
Successfully managing winter storage for canna bulbs is one of the most rewarding skills a gardener can learn. By taking a little time each autumn to lift and protect these tropical rhizomes, you ensure that your garden remains a vibrant, colorful space year after year. For another eye-catching option, browse Canna Tall Tropicanna Black. It is a simple cycle of growth and rest that honors the natural rhythm of the seasons.
At Longfield Gardens, we want every gardener to feel confident in their ability to grow and preserve beautiful plants. With these basic steps, your cannas will remain healthy and strong, ready to burst into growth as soon as the summer sun returns.
- Wait for the signal: Let the first frost tell you when it is time to dig.
- Cure for strength: Allow the rhizomes to dry and toughen up for a week.
- Storage balance: Keep them cool, dark, and slightly damp in a breathable medium.
- Check in: A monthly inspection prevents small issues from becoming big problems.
"The effort you put into storing your cannas today is an investment in a spectacular summer garden tomorrow. Watching those first green shoots emerge in the spring is a wonderful reminder of the resilience and beauty of nature."
FAQ
Can I store canna bulbs in a refrigerator?
It is generally not recommended to store canna rhizomes in a refrigerator. Most home refrigerators are kept at about 35°F to 38°F, which is a bit too cold for cannas and can cause them to deteriorate. Additionally, many refrigerators have low humidity or contain fruits that release gases that can interfere with the dormancy of the rhizomes. A cool basement or garage is a much better choice.
Do I have to wash all the dirt off the rhizomes?
No, you do not have to wash them perfectly clean. In fact, many gardeners prefer to leave a little bit of soil on the rhizomes, as it can provide a small buffer against drying out. As long as you remove the large clumps of wet soil and allow the rhizomes to cure properly, they will store just fine with a bit of dust or dry earth still attached.
How do I know if my canna bulbs died during the winter?
A dead canna rhizome will usually be very lightweight, shriveled, and brittle, or it will be soft and mushy with a foul smell. If you squeeze the rhizome and it feels firm like a carrot or a potato, it is likely still alive. You can also carefully scratch the skin with a fingernail; if you see light-colored, moist flesh underneath, the rhizome is healthy and ready to grow.
Should I fertilize my cannas before I store them?
No, you should stop fertilizing your cannas in late summer, usually about 4 to 6 weeks before you expect the first frost. Adding fertilizer late in the season encourages the plant to produce soft, new growth that is more susceptible to frost damage. You want the plant to focus on slowing down and storing energy in the rhizome rather than pushing out new leaves.