Table of Contents
- Introduction
- Understanding Canna Rhizomes
- When to Dig Your Cannas
- Step-by-Step: How to Dig Canna Rhizomes
- Preparing Rhizomes for Storage
- Choosing the Best Storage Medium
- Selecting the Right Storage Container
- Finding the Ideal Winter Home
- Maintaining Your Cannas During Winter
- Dividing Canna Rhizomes
- Overwintering Cannas in Pots
- Troubleshooting Common Storage Issues
- When to Bring Cannas Back Outside
- Conclusion
- FAQ
Introduction
The bold foliage and vibrant blooms of cannas bring a tropical flair to any backyard. Whether you are growing the striking orange 'Wyoming' or the classic red The President, these plants are often the stars of the summer garden. At Longfield Gardens, we want to help you keep that beauty coming back year after year.
Because cannas are tropical plants, they cannot survive freezing temperatures in most parts of the country. Learning how to store canna bulbs for winter is a rewarding way to save your favorite varieties and grow your collection without starting from scratch each spring. This guide will walk you through the simple process of digging, cleaning, and storing your cannas so they stay healthy until the warm weather returns.
By following a few basic steps, you can ensure your plants have a restful winter and a vigorous start next season. Proper storage is the bridge between a successful summer and an even better one next year, and Spring-Planted Summer-Blooming Bulbs offer plenty of options for a fresh start in spring.
Understanding Canna Rhizomes
Before you head out to the garden with a shovel, it is helpful to understand what you are actually digging up. While many gardeners refer to them as "bulbs," cannas actually grow from rhizomes. A rhizome is a thick, fleshy horizontal stem that grows underground. For a broader overview, see our All About Cannas.
Think of a rhizome as the plant’s energy warehouse. During the summer, the large leaves soak up sunlight and turn it into food, which is then stored in the rhizome. This stored energy is what powers the plant’s rapid growth when spring arrives. Because these structures are fleshy and full of water, they are very sensitive to freezing. If the water inside the rhizome freezes, it damages the plant tissue, leading to rot. If you want more ideas for enjoying these plants in the landscape, our Fresh Ideas for Growing Cannas guide is a useful next step.
We love cannas because they are incredibly resilient and prolific. A single rhizome planted in May can turn into a large clump by October. This natural multiplication means that when you dig them up for the winter, you often end up with more plants than you started with. This makes cannas a wonderful plant for sharing with neighbors or expanding your garden beds.
When to Dig Your Cannas
Timing is the most important factor when preparing for winter storage. You want to give the plants as much time as possible to store energy, but you must get them out of the ground before the soil itself freezes solid.
In most regions, the best signal to start digging is the first frost. A light frost will usually turn the canna leaves black or brown. This might look a bit sad, but it is actually a helpful signal from nature. When the foliage dies back, the plant stops sending energy to the leaves and enters a dormant state.
If you live in a climate where frost comes very late, you can simply wait until the weather turns consistently chilly in late autumn. If the leaves start to yellow and the plant looks like it is finished for the season, it is safe to begin the process.
Key Takeaway: Wait for a light frost to blacken the foliage before digging. This ensures the plant has stored the maximum amount of energy for its winter nap.
Step-by-Step: How to Dig Canna Rhizomes
Digging cannas is a straightforward task that doesn't require specialized tools. A garden spade or a sturdy garden fork is all you need. The goal is to lift the entire clump of rhizomes out of the ground without slicing through the fleshy "fingers" of the plant.
Prepare the Foliage
Start by cutting the stalks down. Use a pair of clean garden pruners or a sharp knife to cut the stems about 2 to 4 inches above the soil line. Removing the bulky leaves makes the digging process much easier and keeps your workspace tidy. The short "stump" left behind acts as a convenient handle while you work.
Loosen the Soil
Cannas grow outward, so the clump of rhizomes is often wider than the base of the stems suggests. To avoid damaging the plant, start digging about 6 to 10 inches away from the center of the plant.
Insert your spade or fork deep into the soil and gently pry upward. Work your way around the entire circle, loosening the soil as you go. You want to feel the soil give way so you can lift the whole mass at once.
Lift the Clump
Once the soil is loose, slide your tool under the center of the clump and lift it out of the hole. If the clump is very large, you may need to lift it in sections, but try to keep it as intact as possible at this stage. Shake off the loose garden soil so you can see the structure of the rhizomes clearly.
Preparing Rhizomes for Storage
After digging, your canna rhizomes need a little preparation before they head into a box for the winter. This stage is all about cleaning and "curing," which helps prevent rot during the dormant months.
Cleaning the Rhizomes
There are two ways to handle the soil remaining on the rhizomes. The easiest method is to simply shake off the big chunks and let the rest dry. Once dry, you can brush away the remaining dirt with your hands or a soft brush.
Alternatively, some gardeners prefer to rinse the rhizomes with a garden hose. Rinsing makes it easier to see any signs of damage or pests, but it also adds a lot of moisture. If you choose to wash your rhizomes, you must be extra diligent during the drying phase. We recommend the "dry and brush" method for beginners because it reduces the risk of trapped moisture.
The Curing Phase
Curing is a fancy word for letting the rhizomes air-dry for a few days. This helps the outer "skin" toughen up and allows any small nicks or cuts from the shovel to heal over.
Place your cleaned rhizomes in a single layer in a dry, well-ventilated area. A garage, a covered porch, or a shed works well. Avoid placing them in direct sunlight or in areas that get very cold at night. Let them sit for two to three days. When the surface feels dry to the touch and the leftover soil has turned to dust, they are ready to be packed away.
Inspect for Health
Before packing, take a moment to look at each clump. Healthy rhizomes should feel firm and heavy for their size. If you find any parts that are soft, mushy, or smell sour, cut those sections away with a clean knife. Only store healthy, firm tissue to ensure you don't spread rot to the rest of your collection.
Choosing the Best Storage Medium
You shouldn't just toss canna rhizomes into an empty plastic bin. To stay healthy, they need a storage environment that manages moisture. If they are too wet, they will rot; if they are bone-dry, they will shrivel up and die.
A storage medium acts as a buffer, holding just enough moisture to keep the rhizome alive while allowing air to circulate. Here are our favorite options:
- Peat Moss: This is a classic choice. It is lightweight and holds a tiny bit of moisture. It also has slightly acidic properties that can help discourage fungal growth.
- Wood Shavings: The kind sold for pet bedding (like pine or cedar) is excellent. It is inexpensive, provides great airflow, and is easy to handle.
- Vermiculite: This mineral-based material is great for moisture control. It is very clean and doesn't break down over time.
- Newspaper: If you are looking for a budget-friendly option, wrapping individual rhizomes in several layers of dry newspaper works surprisingly well.
Place a few inches of your chosen medium in the bottom of a container. Lay the rhizomes on top so they aren't touching each other, then cover them with more medium. This "nesting" approach protects them from temperature swings and keeps them from drying out.
Selecting the Right Storage Container
The container you choose should allow for a little bit of breathing. While plastic bins are popular, they can trap too much moisture if the lid is snapped shut tightly.
- Cardboard Boxes: These are excellent because the material is naturally breathable. They are easy to stack and free to acquire.
- Plastic Totes: If you use plastic, leave the lid slightly ajar or drill several small holes in the sides to allow for airflow.
- Milk Crates: These offer the best ventilation. Line them with newspaper or landscape fabric to keep your storage medium from falling out.
- Paper Bags: For smaller collections, large paper grocery bags are a simple and effective choice.
Whatever you choose, remember to label your containers! It is easy to forget which box holds the City of Portland and which holds the 'Richard Wallace' once they are all tucked away in the dark.
Finding the Ideal Winter Home
Now that your cannas are packed, they need a spot to stay until spring. The ideal storage location is cool, dark, and dry.
The perfect temperature range is between 40°F and 50°F. This is cold enough to keep the plant dormant but warm enough to prevent freezing. If the temperature stays too warm (above 60°F), the cannas might try to start growing in the box. If it drops below freezing, the rhizomes will be damaged. If you want a deeper look at climate effects, our Understanding Cold Hardiness and Heat Tolerance article is a helpful companion piece.
Good storage spots include:
- An unheated (but attached) garage.
- A cool basement or cellar.
- A crawl space.
- A closet in a cool part of the house.
Avoid storing them in a drafty outdoor shed where temperatures will mirror the outside air. Also, keep them away from furnaces or water heaters, as the heat and dry air in those areas will shrivel the rhizomes quickly.
What to do next:
- Find a cool, dark spot in your home that stays between 40°F and 50°F.
- Label your boxes clearly with the variety name and the date.
- Set a monthly reminder on your calendar to check on your plants.
Maintaining Your Cannas During Winter
Storage isn't a "set it and forget it" task. To ensure a high success rate, we recommend checking on your stored rhizomes once a month.
When you check them, look for two things: rot and shriveling.
If you see a rhizome that is turning soft or looks moldy, remove it immediately. One bad rhizome can spread rot to the others in the box. If only a small tip is soft, you can cut it off with a clean knife and let the cut air-dry before putting it back.
If the rhizomes look very wrinkled or feel unusually light, they are losing too much moisture. Use a spray bottle to lightly mist the storage medium with water. You don't want it to be wet—just a tiny bit damp to the touch. This small amount of humidity is often all it takes to keep them plump.
Dividing Canna Rhizomes
One of the best things about storing cannas is seeing how much they have grown. When you dig them up, you will likely find large, heavy clumps. While you can divide them in the fall, we suggest waiting until spring.
In the spring, it is much easier to see the "eyes" (the small bumps where new growth will emerge). Waiting until spring also ensures that you aren't creating fresh wounds on the plant right before it goes into storage. When you are ready to plant in the spring, you can simply break or cut the clumps into smaller sections. Each piece should have at least one or two healthy eyes to ensure it grows into a strong new plant. For step-by-step help with dividing, see our How to Split Canna Lily Bulbs guide.
Overwintering Cannas in Pots
If you grow your cannas in large containers, you have an even easier option. Instead of digging the rhizomes out of the soil, you can store the entire pot.
After the first frost, cut the stalks back just as you would with garden-grown cannas. Move the entire pot into a cool, dark, frost-free area like a basement or garage. Stop watering the pot entirely. The soil will dry out, and the plant will go dormant. For a container-specific refresher, Planting Canna Bulbs in Containers for Tropical Color is a helpful companion piece.
In the spring, about six weeks before the last frost date, you can move the pot back into the light and start watering it again. This is a great "shortcut" for gardeners who only have a few plants and don't want to deal with loose soil and storage bins.
Troubleshooting Common Storage Issues
Most issues with storing cannas come down to moisture levels. If you lead with the correct approach—checking them monthly—you can usually fix problems before they become serious.
If you find your cannas are consistently rotting, it usually means the storage medium was too damp or there wasn't enough airflow. Try using a more breathable container next year, or skip the step of washing the rhizomes with a hose.
If your cannas always shrivel up and don't sprout in the spring, your storage area might be too dry. Adding a bit more peat moss or wood shavings can help provide a better moisture buffer. Every home has a unique microclimate, so it may take one season of observation to find the perfect spot in your house.
When to Bring Cannas Back Outside
The "finish line" for canna storage is the arrival of warm spring weather. Cannas love heat, so there is no rush to get them in the ground.
Wait until the danger of frost has passed and the soil has warmed up to at least 60°F. If you want a head start, you can "wake up" your rhizomes by planting them in pots indoors about a month before you plan to move them outside. This gives them a chance to start growing roots and leaves in a controlled environment, leading to earlier blooms in the summer. If you want a more detailed planting refresher, How to Plant Canna Lily Bulbs covers the basics.
Conclusion
Storing canna bulbs—or rhizomes—for the winter is a simple and rewarding part of the gardening cycle. It allows you to preserve your favorite colors, save money, and watch your garden grow larger every year. By following the signals of the season and providing a cool, dry home for your plants, you can enjoy the lush, tropical beauty of cannas year after year.
- Wait for frost to signal dormancy before you start digging.
- Cure the rhizomes for a few days to let the skin toughen up.
- Store in a breathable container with peat moss or wood shavings.
- Keep them cool and dark, ideally between 40°F and 50°F.
- Check monthly to ensure they stay healthy and firm.
At Longfield Gardens, we believe that gardening should be a rewarding experience for everyone. Taking these simple steps to care for your cannas over the winter ensures that your garden will be even more beautiful next summer. If you’re ready to add more color to your landscape, feel free to browse our collection of premium cannas and other summer-blooming bulbs.
Success with cannas comes down to matching the plant's needs for a cool, dry rest with a simple storage routine. A little bit of preparation in the fall leads to a spectacular show in the summer, and the same approach works well for other summer-blooming bulbs.
FAQ
Do I have to dig up my cannas every year?
Whether you need to dig depends on your USDA hardiness zone. In zones 8 and warmer, cannas can usually stay in the ground all year, especially if you add a thick layer of mulch for insulation. In zones 7 and colder, the ground freezes deep enough to kill the rhizomes, so digging and storing them indoors is necessary for the plants to survive. For a quick zone check, see the Hardiness Zone Map.
Should I wash the dirt off the rhizomes before storing?
You can wash them, but it isn't strictly necessary. Many gardeners find it easier to let the soil dry and then gently brush it off. If you do choose to wash them with a hose, make sure you allow them to air-dry completely in a well-ventilated area for several days to prevent trapped moisture from causing rot during storage.
What happens if I forget to dig them up before a hard freeze?
A light frost that kills the leaves is actually beneficial, but a hard freeze that freezes the soil can damage the rhizomes. If you forget to dig them and the ground freezes, check the rhizomes as soon as possible. If they are still firm and not mushy, you can proceed with storage, but keep a very close eye on them for signs of rot over the winter.
Can I store cannas in the refrigerator?
While a refrigerator provides a consistent cool temperature, it is usually too cold and lacks the necessary airflow for canna storage. Most refrigerators are kept at 35–38°F, which is just on the edge of being too chilly for tropical rhizomes. A cool basement, crawl space, or an unheated closet is a much better environment for successful overwintering.