Table of Contents
- Introduction
- Understanding Canna Rhizomes
- When to Begin the Preservation Process
- Step-By-Step: How to Dig Canna Bulbs
- The Importance of Curing
- Choosing the Best Storage Container and Medium
- Finding the Right Storage Location
- Monitoring Your Cannas Through the Winter
- Storing Cannas Grown in Containers
- Preparing for Spring Replanting
- Why Some Rhizomes Fail (and Why Not to Worry)
- Summary of Canna Preservation Steps
- FAQ
Introduction
Canna lilies are the champions of the summer garden. With their lush, banana-like leaves and bold, tropical flowers, they provide a sense of exotic beauty that few other plants can match. One of the most rewarding parts of growing these stunning plants is that they get better with age. As the clumps grow larger each season, you get more flowers and a more impressive display in your yard. If you’re shopping for new varieties, our Tall Cannas collection is a great place to start.
To keep that beauty going year after year, many gardeners need to bring their plants indoors for the winter. At Longfield Gardens, we want to make sure your favorite varieties return even bigger and better next spring. Preserving canna bulbs—which are technically called rhizomes—is a straightforward process that anyone can master. It only takes a little bit of time in the fall to ensure a lifetime of summer color. For a broader selection, browse our Assorted Cannas.
This guide will walk you through the entire process of lifting, cleaning, and storing your cannas. Whether you are a beginner or a seasoned gardener, these steps will help you protect your investment and enjoy your garden to the fullest. By understanding the simple needs of these tropical plants during their dormant period, you can ensure they wake up healthy and ready to grow when the warm weather returns. You can also read All About Cannas for more background on planting and growing.
Understanding Canna Rhizomes
Before we dig in, it is helpful to know exactly what we are working with. While most gardeners call them "bulbs," cannas actually grow from rhizomes. A rhizome is a thick, fleshy underground stem that stores energy and water for the plant. If you look closely at one, you will see "eyes" or small bumps. These are the points where new stems will sprout in the spring. For gardeners who prefer mid-sized plants, our Medium Cannas offer plenty of options.
Cannas are tropical plants by nature. They thrive in heat and humidity, which makes them perfect for summer gardens across the United States. However, they are not built to withstand freezing temperatures. In USDA hardiness zones 8 through 11, cannas can often stay in the ground all year long with a thick layer of mulch. But if you live in zone 7 or colder, the frost will likely reach the rhizomes and cause them to rot. Longfield Gardens also provides Spring-Planted Summer-Blooming Bulbs for gardeners looking for more warm-season color.
This is why preserving them is such a valuable skill. Instead of buying new plants every year, you can save the ones you already love. Because these rhizomes naturally multiply underground during the summer, you will often find that you have twice as many plants in the fall as you started with in the spring. It is a wonderful way to expand your garden for free.
When to Begin the Preservation Process
Timing is the most important factor when it comes to successfully preserving canna bulbs. You want to give the plants as much time as possible to store energy in their rhizomes, but you must get them out of the ground before a deep freeze sets in. If you’re planning ahead for shipping and planting, review our Shipping Information.
The Signal from Nature
The best time to dig up your cannas is shortly after the first light frost of autumn. You will know it has happened when the tops of the leaves turn black or brown and begin to wither. This change looks a bit sad, but it is actually a helpful signal. The frost tells the plant that the growing season is over and it is time to go dormant.
Dormancy is a state of "sleep" where the plant stops growing to protect itself from the cold. When the foliage dies back, the plant shifts its remaining energy down into the rhizome. Waiting for this first frost ensures that the rhizome is as "charged up" as possible for its long winter nap.
Watching the Weather
If you live in an area where the ground freezes solid quickly, you should keep a close eye on the forecast. While a light surface frost kills the leaves, it usually does not hurt the rhizomes buried a few inches deep. However, a "hard freeze"—where the ground itself begins to freeze—can be fatal. If a significant cold snap is predicted and your cannas haven't seen a frost yet, it is perfectly fine to dig them up a little early.
Key Takeaway: Always aim to dig your cannas after the first frost has blackened the leaves, but before the ground freezes solid. This timing gives the rhizomes the best chance at a healthy dormancy.
Step-By-Step: How to Dig Canna Bulbs
Lifting cannas is a physical task, but it shouldn't be a stressful one. The goal is to get the rhizomes out of the dirt with as little damage as possible. Wounds or bruises on the fleshy rhizome can provide an entry point for disease or rot during the winter months.
Prepare the Plants
Before you pick up a shovel, start by cutting the stems back. Use a clean pair of garden shears to trim the stalks down to about 2 or 3 inches above the soil line. Removing the bulky foliage makes it much easier to see where you are digging. It also prevents the long stems from acting like levers that could snap the rhizome clumps apart unexpectedly.
Lift the Clumps
Cannas are vigorous growers, and their root systems can be surprisingly wide. To avoid cutting into the rhizomes, start your digging about 6 to 8 inches away from the base of the stems.
- Use a garden fork or a sturdy spade to dig straight down around the entire perimeter of the plant.
- Slowly pry upward from different sides to loosen the soil.
- Once the soil is loose, gently lift the entire clump out of the ground.
If you have a very large, established patch of cannas, the clumps can be heavy. Don't be afraid to ask for a hand or to break the very large clumps into manageable sections using your hands or a spade.
Clean Away the Soil
Once the rhizomes are out of the ground, you need to remove the excess dirt. You can do this by gently shaking the clump or using your hands to brush away the soil. Some gardeners prefer to use a garden hose to rinse the rhizomes clean. Rinsing makes it easier to inspect the health of the plant and see the "eyes."
If you choose to rinse them, just be sure to do it gently. Do not use a high-pressure nozzle or a scrub brush, as this can tear the skin. Once they are clean, let them sit in a shaded, dry spot for an hour or two so the surface moisture can evaporate.
The Importance of Curing
One of the most common mistakes gardeners make when preserving canna bulbs is putting them directly into storage while they are still "fresh" and wet. To prevent rot, the rhizomes need to go through a process called curing.
Curing is simply allowing the rhizomes to air-dry for a short period. This process allows the outer skin to toughen up and any small nicks or cuts from the digging process to "callus" over. A callused cut is like a scab on a knee; it acts as a protective barrier against fungi and bacteria.
How to Cure Your Cannas
Place your cleaned rhizomes in a single layer on a tray, a piece of cardboard, or a screen. Keep them in a warm, dry area with plenty of air circulation. A garage, a garden shed, or even a covered porch works well, as long as the temperature stays above freezing.
Ideally, you should cure them for about 7 to 10 days. During this time, the leftover soil will turn to dust and fall off, and the cut stems will begin to dry out. Once the outer skin feels firm and dry to the touch, they are ready for their winter home. If you enjoy growing standout varieties, see our Canna Tall Tropicanna Black.
What to Do Next:
- Cut stems to 3 inches.
- Dig 8 inches away from the plant to avoid damage.
- Rinse or brush off loose soil.
- Let rhizomes air-dry in a warm, ventilated spot for one week.
Choosing the Best Storage Container and Medium
The goal of winter storage is to keep the rhizome alive but "asleep." You want to prevent two things: freezing and drying out completely. If the rhizome gets too cold, it dies. If it loses all its moisture, it will shrivel up and fail to grow in the spring.
The Storage Medium
To maintain the right moisture balance, we recommend packing the rhizomes in a "storage medium." This is a loose material that holds just enough humidity to keep the plant hydrated but is dry enough to prevent mold. Popular choices include:
- Peat Moss: This is the most common choice. It is sterile and holds moisture well.
- Vermiculite: A mineral that provides excellent aeration and moisture control.
- Coarse Sawdust or Wood Shavings: These are great for airflow and are often very affordable.
- Newspaper: You can wrap each rhizome individually in a few sheets of dry newspaper.
The Container
You want a container that allows for a small amount of air exchange. Plastic bins with the lids left slightly ajar, cardboard boxes, or even paper grocery bags are excellent choices. Avoid using airtight plastic bags or sealed containers, as these trap moisture and almost always lead to rot.
How to Pack
Start by placing a 2-inch layer of your chosen medium at the bottom of the container. Lay the rhizomes on top, making sure they aren't crowded or touching each other too much. Cover them with more medium until they are completely tucked in. If you have a lot of cannas, you can create multiple layers, as long as there is medium between each one.
Finding the Right Storage Location
Your cannas need a "Goldilocks" environment: not too hot, not too cold, but just right. The ideal temperature range is between 40°F and 55°F.
Why Temperature Matters
If the storage area is too warm (above 60°F), the rhizomes might think it is spring and try to start growing in the dark. This wastes their stored energy. If the area is too cold (below 35°F), they are at risk of freezing.
Best Locations
- Unheated Basements: Usually the best option for most homeowners. They stay cool and relatively humid.
- Crawl Spaces: These often maintain a very consistent temperature throughout the winter.
- Attached Garages: These can work well, but you must ensure the box is kept away from the exterior walls or the floor where it might get too cold.
- Root Cellars: The traditional choice for a reason! They provide the perfect dark, cool, and damp environment.
Monitoring Your Cannas Through the Winter
Preserving canna bulbs isn't a "set it and forget it" task. To ensure the highest success rate, you should check on your stored rhizomes about once a month. This only takes a few minutes but can save your entire collection if an issue arises. For zone-specific timing, the Learn about Hardiness Zone tool is useful.
What to Look For
When you open your storage boxes, look for two things: rot and desiccation (extreme drying).
Dealing with Rot: If you see a rhizome that looks fuzzy, smells bad, or feels soft and mushy, remove it immediately. Rot can spread quickly from one plant to another. If only a small tip of a large rhizome is soft, you can cut that part off with a clean knife and let the healthy part air-dry before putting it back.
Dealing with Shrivelling: If the rhizomes look very wrinkled or feel light and "corky," they are losing too much moisture. To fix this, use a spray bottle to lightly mist the storage medium with a little water. You don't want it to be wet—just slightly damp, like a wrung-out sponge. This will provide enough humidity to stop the shrivelling.
Key Takeaway: A quick monthly check is your best defense. Remove anything mushy and lightly mist the packing material if everything feels bone-dry.
Storing Cannas Grown in Containers
If you grow your cannas in pots, you have an even easier path to preservation. You don't necessarily have to dig the rhizomes out of the soil. Instead, you can store the entire pot.
- Cut back the foliage: After the first frost, cut the stems down to the soil line just like you would for garden-grown plants.
- Stop watering: Allow the soil in the pot to dry out completely.
- Move the pot: Carry the entire container to your cool, dark storage area. The dry soil in the pot acts as the storage medium, protecting the rhizomes from temperature swings.
- Spring wakeup: In the spring, you can bring the pot back into the light, give it a good soak, and wait for the new shoots to appear. This is also a great time to tip the pot over and divide the rhizomes if they have become too crowded.
Preparing for Spring Replanting
As winter fades and the days grow longer, you will start to look forward to getting back into the garden. In early spring, about 4 to 6 weeks before the last expected frost, it is time to check your cannas one last time.
Dividing Your Rhizomes
This is the perfect time to propagate your plants. If you started with one large clump in the fall, you can now break or cut it into several smaller pieces. Each piece should have at least one or two "eyes" (the little bumps where growth begins). Using a clean knife makes the job easy. Let the cut pieces sit for a day to callus before planting. If you want more planting inspiration, Longfield Gardens’ How-To guides are a helpful next step.
Getting a Head Start
If you live in a region with a short growing season, you can "wake up" your cannas indoors. Plant the rhizomes in pots with some potting soil and place them in a sunny window or under grow lights. By the time the weather is warm enough to plant them outside, you will already have several inches of green growth.
Wait until the soil has warmed up to at least 60°F and all danger of frost has passed before moving them to their permanent summer home. Cannas love the sun, so choose a spot that gets at least 6 to 8 hours of direct light. If you want to compare more colors and sizes, browse our Canna Medium The President.
Why Some Rhizomes Fail (and Why Not to Worry)
Even with the best care, not every single rhizome will survive the winter. Most experienced gardeners are very happy with an 80% survival rate. Factors like the age of the plant, the weather during the previous summer, and small variations in storage humidity can all play a role.
If you lose a few to rot, don't be discouraged. Because cannas multiply so vigorously, the ones that do survive will likely provide enough new growth to fill in the gaps. Gardening is a learning process, and every season gives you more insight into the specific microclimate of your home and storage areas.
At Longfield Gardens, we believe that the joy of seeing those first tropical leaves unfurl in the summer far outweighs the small effort of winter storage. With these simple steps, you can keep your garden glowing with color year after year. If you’re still deciding which style suits you best, our Canna Assorted Collection is a good way to try multiple varieties.
Summary of Canna Preservation Steps
Preserving your cannas is a cycle that follows the rhythm of the seasons. By respecting the plant's need for dormancy and protection, you ensure a spectacular display every summer.
- Wait for the frost: Let the first light frost signal the start of dormancy.
- Dig with care: Keep your shovel at a distance to avoid wounding the rhizomes.
- Cure completely: Never skip the drying phase; it is the most important step for preventing rot.
- Control the environment: Keep them cool, dark, and slightly humid.
- Monitor monthly: A quick check ensures small problems don't become big ones.
"Preserving your canna rhizomes is like putting a piece of summer into a time capsule. When you open those boxes in the spring, you aren't just looking at roots; you're looking at the future of your garden."
By following these practical steps, you can enjoy the lush, tropical beauty of cannas no matter where you live. It is an easy, rewarding way to grow your garden and keep your favorite plants thriving for years to come. If you're looking to add new colors or textures to your collection, we invite you to explore our Tall Cannas selection at Longfield Gardens and find the perfect match for your landscape.
FAQ
Do I have to wash the dirt off the canna bulbs before storing?
While it isn't strictly mandatory, rinsing or brushing off the soil is highly recommended. Cleaning the rhizomes allows you to inspect them for pests or soft spots and makes it easier to see the "eyes" for future division. If you do wash them, ensure they are allowed to cure and dry completely for about a week before they are packed away. For more shipping and timing details, see our Shipping Information.
Can I store canna bulbs in my refrigerator?
It is generally not a good idea to store canna rhizomes in a refrigerator. Most refrigerators are kept around 35-38°F, which is a bit too cold for tropical cannas, and the air inside is often very dry. Additionally, many fruits and vegetables in the fridge release ethylene gas, which can cause the rhizomes to spoil or fail to sprout in the spring. A cool basement or garage is a much better choice.
What should I do if my stored canna bulbs have white mold on them?
If you see a light dusting of white mold, it usually means the air is too still or the storage medium is a bit too damp. Wipe the mold off with a dry cloth and leave the container open for a day or two to improve airflow. If the rhizome itself is firm, it will likely be fine. However, if the mold is accompanied by soft, mushy flesh, that part should be cut away or the rhizome discarded.
How do I know if my canna bulbs are dead or just dormant?
Healthy dormant rhizomes should feel firm and heavy for their size, similar to a fresh ginger root or a potato. If a rhizome feels very light, hollow, or shrivelled like a raisin, it has likely dried out too much and may be dead. If it is soft, slimy, or has a foul odor, it has rotted. If it’s firm and has visible "eyes" or buds, it is simply sleeping and ready for spring.