Canna Bulbs How to Store: A Simple Step-by-Step Guide

Introduction
Why Storing Canna Rhizomes Is a Great Idea
When to Start the Storage Process
Tools You Will Need
Step 1: Cutting Back the Foliage
Step 2: Digging Up the Rhizomes
Step 3: Cleaning and Curing
Step 4: Choosing Your Storage Container
Step 5: The Packing Material
Step 6: Finding the Right Location
Monitoring Your Cannas During Winter
Dividing Rhizomes in the Fall vs. Spring
Overwintering Cannas in Pots
Preparing for Spring
Common Myths About Canna Storage
Creating a Successful Routine
Conclusion
FAQ

Introduction

There is nothing quite like the tropical flair that cannas bring to a summer landscape. With their towering stems and vibrant, petal-rich blooms, they transform any backyard into a lush retreat. At Longfield Gardens, we love how these resilient plants provide months of color with very little effort. If you live in a region with cold winters, you don’t have to treat these beauties as annuals.

Knowing how to store canna bulbs properly ensures you can enjoy the same stunning flowers year after year. This guide is designed for home gardeners who want a reliable, straightforward method for overwintering their rhizomes. We will cover the best time to dig them up, how to prepare them for rest, and the ideal conditions for a successful winter dormancy. Learning the right way to store your cannas is a rewarding skill that saves money and lets you grow a larger, more impressive garden each season.

Why Storing Canna Rhizomes Is a Great Idea

Cannas are technically tropical plants that grow from underground stems called rhizomes. In warmer climates, specifically USDA zones 8 through 11, these plants can usually stay in the ground all year. However, in most of the United States, the ground freezes deep enough to damage or kill the rhizomes if they are left outside.

Choosing to store your cannas is a smart way to protect your gardening investment. Each year a canna grows, its rhizome system expands. By digging them up and keeping them safe, you aren't just saving the plant; you are often gaining more plants for the following year. When you pull them out of storage in the spring, you will likely find that they have grown large enough to be divided into several new sections.

When to Start the Storage Process

Timing is everything when it comes to preparing cannas for their winter nap. You want the plant to stay in the ground as long as possible so it can store energy, but you must get it out before the ground freezes solid.

The best signal to start digging is the first light frost of autumn. You will notice the lush green or bronze foliage turns black or brown almost overnight after a cold snap. This is actually a good thing. The cold temperature tells the plant to stop sending energy to the leaves and start focusing on the rhizome.

If you live in an area where frost comes very late, you can simply wait until late October or early November. The goal is to wait for the plant to naturally begin its dormant phase. Once the foliage has withered from the cold, you are ready to begin.

Key Takeaway: Wait for the first frost to blacken the leaves before digging. This ensures the rhizome has gathered all the energy it needs for the winter.

Tools You Will Need

Having the right tools ready makes the process quick and prevents accidental damage to the plants. You don’t need specialized equipment, but a few basics will help:

A garden fork: This is often better than a shovel because it is less likely to slice through the rhizomes.
Pruning shears or a sharp garden knife: For cutting back the heavy stems.
A garden hose: To wash away excess soil.
Storage containers: Cardboard boxes, plastic bins with ventilation, or breathable paper bags work well.
Packing material: This helps maintain moisture levels. Options include peat moss, vermiculite, perlite, or even clean wood shavings.
Labels and a marker: It is very easy to forget which variety is which once the leaves are gone.

Step 1: Cutting Back the Foliage

Once the frost has nipped the leaves, the first task is to clear the top growth. Use your pruning shears to cut the stems down to about 2 to 4 inches above the soil line.

Removing the bulk of the foliage makes it much easier to see where the base of the plant is. It also prevents the old, decaying leaves from attracting pests or mold while you are trying to dry the rhizomes. Don't worry about being too precise with the height; leaving a small "handle" of the stem actually makes the rhizomes easier to move around during the cleaning process.

Step 2: Digging Up the Rhizomes

When you are ready to dig, start several inches away from the base of the plant. Canna rhizomes grow horizontally and can spread out further than you might expect. If you dig too close to the stem, you risk chopping the rhizome into pieces.

Insert your garden fork into the soil about 6 to 8 inches away from the stem.
Gently pry upward to loosen the soil all the way around the plant.
Once the soil is loose, grab the remaining stem "handle" and lift the entire clump out of the ground.
Shake off the heavy clumps of dirt.

If the soil is very wet or heavy with clay, you may need to use your hands to gently pull away the larger pieces of earth. Be careful not to bruise the outer skin of the rhizomes, as these marks can become entry points for rot during the winter.

Step 3: Cleaning and Curing

At this stage, you have a few choices depending on your soil type. Many gardeners prefer to wash the rhizomes clean with a garden hose. This makes it easier to inspect them for any signs of damage or pests. If your soil is sandy and falls away easily, a quick shake might be all you need.

After cleaning, the rhizomes need to "cure." This is a short drying period that allows the outer skin to toughen up slightly.

Find a dry, shaded spot—like a garage, a porch, or a shed—and spread the rhizomes out in a single layer. Avoid direct sunlight, as this can dry them out too quickly or even cook them. Let them sit for two to three days. You aren’t trying to dry them out completely; you just want the surface moisture to evaporate. If the rhizomes feel dry to the touch and the cut ends of the stems have started to callus over, they are ready for the next step.

What to do next:

Remove any soft or mushy spots you find during cleaning.

Ensure the rhizomes are not touching each other while curing to allow air circulation.

Double-check that your labels are still attached to each clump.

Step 4: Choosing Your Storage Container

There is no "one size fits all" container for canna bulbs, but the goal is always the same: keep them cool, dark, and slightly moist.

Cardboard Boxes These are a favorite for many because they are breathable. They allow a small amount of air exchange, which prevents the build-up of moisture that leads to mold.

Plastic Tubs If you use plastic bins, do not snap the lid on tight. You can drill a few small holes in the sides for ventilation or simply leave the lid resting loosely on top. If the bin is airtight, the rhizomes will likely rot.

Paper Bags For smaller collections, heavy-duty grocery bags work well. They are breathable and easy to tuck away on a shelf.

Step 5: The Packing Material

This is perhaps the most important part of knowing how to store canna bulbs. If you leave the rhizomes completely exposed to the air, they may shrivel and die. If you keep them too wet, they will rot. The packing material acts as a buffer to maintain that perfect middle ground.

We have found that slightly damp peat moss or vermiculite provides excellent results. You can also use sawdust or perlite.

Place a 2-inch layer of your chosen material at the bottom of your container.
Lay the rhizomes on top in a single layer. They should not be packed tightly or touching each other if possible.
Cover the layer with more packing material.
If you have a lot of bulbs, you can stack a second layer, but keep a layer of material between them.

The packing material should feel like a wrung-out sponge—barely damp, not wet. If you are using peat moss and it feels dusty, give it a very light misting with a spray bottle before packing.

Step 6: Finding the Right Location

The ideal storage location is a spot that stays consistently between 40°F and 50°F. This temperature range is cold enough to keep the plant dormant but warm enough to prevent freezing.

Unheated Basements: Often provide the perfect temperature and humidity.
Crawl Spaces: Usually a good choice as long as they stay above freezing.
Cool Closets: If you have an entryway closet that stays chilled, this can work.
Attached Garages: Be cautious here. While many garages stay cool, they can drop below freezing during a polar vortex. If you use a garage, keep the boxes off the concrete floor and perhaps wrap them in an old blanket for extra insulation.

Avoid storing your cannas near a furnace, water heater, or any heat vents. The warmth will trick the bulbs into thinking it’s spring, causing them to sprout prematurely and exhaust their energy.

Monitoring Your Cannas During Winter

Storage isn't a "set it and forget it" task. At least once a month, you should take a peek inside your storage containers. This quick check takes only a minute but can save your entire collection.

Look for two things: rot and shriveling.

Dealing with Rot If you see a rhizome that has turned mushy or has visible fuzzy mold, remove it immediately. One rotting bulb can quickly spread to its neighbors. If the packing material feels soggy, replace it with fresh, drier material.

Dealing with Shriveling If the rhizomes look wrinkled or feel exceptionally light, they are losing too much moisture. Use a spray bottle to give the packing material a light misting. You don't want to soak it—just add enough humidity to stop the drying process.

Key Takeaway: A monthly "wellness check" allows you to catch moisture issues early, ensuring your rhizomes stay healthy until spring.

Dividing Rhizomes in the Fall vs. Spring

One question we often hear is whether to divide the clumps before or after storage. Both methods work, but there are advantages to each.

Dividing in the fall saves space. If you have a small storage area, breaking large clumps into smaller 3- to 5-inch pieces allows you to fit more into a single box. However, every cut you make creates a wound that needs to heal.

Many gardeners prefer to wait until spring to divide. In the spring, you can clearly see the "eyes" (the small bumps where new growth will emerge). This makes it much easier to ensure every piece you cut has at least one or two healthy growing points. At our trial gardens, we often wait until spring to divide, as it gives us a better look at which parts of the rhizome are the most vigorous.

Overwintering Cannas in Pots

If you grow your cannas in large containers, you have a shortcut! You don't necessarily need to dig them out of the soil.

Once the first frost hits, cut the stems back just like you would for garden-grown plants. Move the entire pot into a cool, frost-free location like a basement or garage. Stop watering the pot completely. The soil will dry out, and the plant will go dormant.

In the spring, you can either pull the rhizomes out to refresh the soil and divide them, or simply move the pot back outside and start watering again once the weather warms up. This is an excellent option for those with limited time or storage space.

Preparing for Spring

As winter fades and the ground begins to thaw, it’s time to start thinking about the upcoming season. About four to six weeks before the last expected frost, you can bring your containers out of their cool storage spot.

This is the perfect time to divide any large clumps. Use a sharp, clean knife to cut the rhizomes into sections. Ensure each section has at least two "eyes." Let the cuts dry for a day before planting.

If you want to get a head start on the growing season, you can "start" your cannas indoors in pots. Place the rhizomes in potting soil, keep them in a warm, sunny spot, and give them a little water. By the time the outdoor temperatures are safely above 60°F, you will have established plants ready to go into the garden.

Common Myths About Canna Storage

There is a lot of advice out there, and some of it can be confusing. Let’s clear up a few common misconceptions:

"You must use fungicides." While some people use sulfur powder or fungicides, it is usually not necessary if your rhizomes are healthy and your storage conditions are dry and cool.
"They need to stay bone-dry." If a rhizome loses all its internal moisture, it won't have the energy to sprout. Think of it like a potato; it needs to stay firm.
"You can't store them if they've been frozen." If only the leaves froze, the plant is fine. If the ground froze deep enough to turn the rhizome into a mushy ice block, then it likely won't survive. This is why we emphasize getting them inside before the deep winter freezes arrive.

Creating a Successful Routine

Gardening is most enjoyable when it feels like a natural rhythm rather than a chore. Storing cannas is part of that seasonal cycle. In the spring, you experience the excitement of planting and the anticipation of blooms. In the summer, you enjoy the lush tropical beauty. In the fall, there is a quiet satisfaction in tucking your plants away safely, knowing they will return even bigger and better next year.

At Longfield Gardens, we believe that every gardener can find success with these simple steps. Whether you have a single favorite plant or a massive border filled with different varieties, the process is the same. It’s all about working with the plant's natural life cycle.

Conclusion

Storing canna bulbs is one of the most effective ways to build a spectacular garden over time. By following the simple steps of waiting for the frost, cleaning the rhizomes gently, and providing a cool, breathable home for the winter, you ensure your tropical favorites return year after year.

Wait for a light frost to trigger dormancy.
Clean and cure the rhizomes for 2-3 days before packing.
Use a breathable container with slightly damp peat or wood shavings.
Keep the storage area between 40°F and 50°F.
Check monthly for any signs of rot or drying.

The effort you put in during the autumn months pays off in a big way when the summer heat arrives. We invite you to explore the many beautiful varieties available and enjoy the process of growing these magnificent plants. With a little care, your cannas will be a highlight of your garden for many seasons to come.

Storing your cannas is not just about saving a plant; it's about preserving a piece of summer to enjoy all over again next year.

FAQ

How do I know if my stored canna bulbs are still alive?

Healthy rhizomes should feel firm and heavy for their size, much like a fresh ginger root or a potato. If you gently scratch the surface with your fingernail, you should see creamy white or light-colored flesh underneath. If the rhizome is mushy, hollow, or crumbles when touched, it is likely no longer viable.

Can I store canna bulbs in the refrigerator?

While a refrigerator is cool and dark, it is generally too cold and lacks the proper humidity for canna rhizomes. The temperature in most refrigerators is set below 40°F, which can damage the tender tissues of the bulb. Additionally, refrigerators often have low humidity which can cause the rhizomes to shrivel quickly.

Should I wash the dirt off before storing?

Yes, it is generally better to wash or brush off the bulk of the soil. Soil can hold excessive moisture or hide pests like slugs or insects that might damage the rhizome during dormancy. However, ensure the rhizomes are completely dry on the outside before you pack them away in their storage containers.

What happens if I don't dig up my cannas?

If you live in USDA zones 7 or colder and leave your cannas in the ground, the freezing winter temperatures will likely kill the rhizomes. In zone 7, you might have success by applying a very thick layer of mulch (6-12 inches) over the planting area, but in colder zones, digging and storing them indoors is the only way to ensure they survive the winter.