Storing Canna Bulbs for Winter

Table of Contents

1. Introduction
2. Understanding Canna Rhizomes
3. When to Dig: Watching for the First Frost
4. Preparing the Plants for Harvest
5. Digging Your Canna Rhizomes
6. Cleaning and Sorting the Clumps
7. The Importance of Curing
8. Choosing a Storage Medium
9. Packing Your Cannas for the Winter
10. Finding the Perfect Storage Location
11. Winter Check-ups: Monitoring Your Collection
12. Managing Container-Grown Cannas
13. Bringing Cannas Out of Dormancy
14. Troubleshooting Common Storage Issues
15. Why Storing Your Own Bulbs is Worth the Effort
16. Conclusion
17. FAQ

Introduction

There is nothing quite like the tropical flair that cannas bring to a summer garden. Their bold foliage and vibrant blooms turn any backyard into a lush retreat, providing color and texture from early summer right through the first chilly days of autumn. At Longfield Gardens, we love how these easy-to-grow plants transform a landscape with minimal effort during the height of the heat.

As the growing season draws to a close, you might wonder how to preserve that tropical beauty for next year. While cannas are incredibly vigorous, they are tender plants that cannot survive freezing temperatures in most parts of the United States. Learning the simple steps for storing these plants over the winter ensures you can enjoy your favorite varieties year after year without needing to buy new ones every spring. For a fuller refresher on the basics, see How to Overwinter Canna Lily Bulbs.

This guide will walk you through the entire process of harvesting, curing, and storing your canna rhizomes. Whether you are a beginner or a seasoned gardener, you will find practical tips to keep your plants healthy and dormant until the warm weather returns. Storing your cannas is a rewarding way to build a massive garden display over time as your collection grows and multiplies.

With the right timing and a few basic supplies, you can successfully overwinter your cannas and look forward to an even more spectacular show next season.

Understanding Canna Rhizomes

To store cannas successfully, it helps to understand what you are actually digging up. Although most gardeners call them "bulbs," cannas actually grow from rhizomes. A rhizome is a thick, fleshy underground stem that grows horizontally. These structures act as the plant’s pantry, storing energy and nutrients during the growing season to fuel the next year’s growth.

During the summer, your cannas use sunlight and water to expand these rhizomes. By the time autumn arrives, a single rhizome planted in the spring has often grown into a large, heavy clump with multiple "eyes" or growing points. Each eye has the potential to become a new stalk next year. Because these structures are so full of moisture, they are very sensitive to the expansion of ice. If the water inside the rhizome freezes, the cells rupture, and the plant will rot once the ground thaws.

Storing cannas is simply the process of helping the plant enter a deep sleep, or dormancy. By removing them from the frozen ground and keeping them in a cool, dark place, you protect that stored energy. When you bring them back out in the spring, they will be rested and ready to sprout as soon as they feel the warmth of the sun and the touch of damp soil. For a broader overview of planting and growing, read All About Cannas.

When to Dig: Watching for the First Frost

Timing is everything when it comes to storing canna bulbs for winter. If you dig them too early, the plant may not have finished storing all the energy it needs for the winter. If you wait too long, a deep freeze could damage the rhizomes. The goal is to find the perfect window when the plant has received the signal to go dormant but the soil is still workable.

In most regions, the best signal is the first light frost. You will know it has happened when the lush green or bronze leaves of your cannas suddenly turn black or dark brown. This might look like a sad end to the season, but it is actually a helpful part of the process. The frost tells the plant that winter is coming and it is time to shut down.

Once the foliage has been "zapped" by frost, you generally have a window of a few days to a couple of weeks to get them out of the ground. You want to complete the task before the ground itself freezes solid. In warmer climates, such as USDA zones 8 through 11, the ground rarely freezes deep enough to hurt cannas, and they can often stay in the soil year-round with a bit of mulch. However, for gardeners in zones 7 and colder, digging is the best way to guarantee their survival.

Key Takeaway: The first frost is your friend. It acts as a natural "off switch" for your cannas, signaling that it is time to move the rhizomes into storage for their winter nap.

Steps to Take Before the Frost

• Label your varieties: Before the frost turns all the leaves brown, mark which plants are which. Use garden stakes or waterproof tags to note the color and height.
• Check the forecast: Keep an eye on local weather reports for the first killing frost in your area.
• Prepare your supplies: Have your shovels, crates, and storage medium ready so you aren't rushing when the weather turns cold.

Preparing the Plants for Harvest

Before you reach for your shovel, you need to clear away the spent foliage. This makes the digging process much easier and cleaner. Using a pair of sharp garden shears or a lopper, cut the stalks down so only about two to four inches of stem remain above the soil line.

Cutting the stalks back accomplishes two things. First, it removes the bulk of the plant, allowing you to see exactly where the base of the clump is. This helps you avoid accidentally stabbing the rhizomes with your shovel. Second, these short "stubs" of stems act as convenient handles when you are lifting the heavy clumps out of the earth.

Dispose of the blackened foliage in your compost pile, provided the plants were healthy throughout the season. If you noticed any signs of pests or disease during the summer, it is better to discard the foliage in the trash to prevent those issues from overwintering in your garden.

Digging Your Canna Rhizomes

Digging cannas requires a bit of muscle but should be done with a gentle touch. Because the rhizomes are fleshy, they can be easily bruised or sliced. A wound on a rhizome is an open door for fungi and bacteria, which can lead to rot during storage.

Start by stepping back about six to eight inches from the base of the plant. It is better to start too far away and find nothing than to start too close and slice through a healthy rhizome. Use a garden spade or a sturdy garden fork to dig a circle all the way around the plant. This loosens the soil and severs the smaller "feeder" roots that anchor the plant.

Once you have loosened the soil around the entire perimeter, gently pry the clump upward. You may need to repeat the prying motion from a few different angles to lift the entire mass. Canna clumps can be surprisingly heavy and large, often reaching the size of a basketball if they had a good growing season.

Tips for Successful Digging

• Use a garden fork: A fork is often better than a spade because it is less likely to slice clean through a rhizome.
• Work when it’s dry: If possible, dig on a day when the soil is relatively dry. This makes it much easier to shake off the excess earth.
• Lift, don't pull: Never try to pull the clump out by the stems alone, as they can snap off, leaving the rhizome stuck in the ground.

Cleaning and Sorting the Clumps

Once the clumps are out of the ground, the next step is to remove the excess soil. You can do this by gently shaking the clump or using your hands to brush away large clods of dirt. Some gardeners prefer to wash their rhizomes with a garden hose to get them perfectly clean. While this makes it easier to inspect for damage, it also adds a lot of moisture that must be dried off later.

If you choose to wash them, use a gentle spray. Once the dirt is gone, take a close look at each rhizome. You are looking for firm, plump structures. If you see any parts that feel mushy, look shriveled, or show signs of insect tunnels, use a clean knife to trim those sections away.

At this stage, you might be tempted to divide the large clumps into smaller pieces. While you certainly can do this now, many experts at Longfield Gardens suggest waiting until the spring. Keeping the clumps larger over the winter helps protect the inner rhizomes from drying out too much. If a clump is simply too big to handle, you can break it into two or three manageable sections, making sure each section has at least a few healthy-looking eyes.

Key Takeaway: Clean rhizomes are easier to monitor for rot. Whether you shake off the dirt or wash it away, the goal is to have a clear view of the plant's health before it goes into storage.

The Importance of Curing

Curing is perhaps the most overlooked step in storing canna bulbs for winter, but it is one of the most important. Curing is the process of allowing the outer skin of the rhizome to dry and toughen up slightly. This creates a natural protective barrier that prevents moisture from escaping and pathogens from entering.

To cure your cannas, find a spot that is out of direct sunlight but has excellent air circulation. A garage, a covered porch, or a shed works well. Spread the rhizomes out in a single layer on a piece of cardboard or a mesh screen. Do not stack them, as this can trap moisture and lead to mold.

The curing process usually takes between three and seven days. You will know they are ready when the outer surfaces feel dry to the touch and any remaining soil has turned into a dry powder. If you washed your rhizomes, they might need an extra day or two to ensure the "nooks and crannies" are completely dry.

Choosing a Storage Medium

You cannot simply toss canna rhizomes into a plastic bin and hope for the best. Without some kind of packing material, they will either rot from trapped moisture or shrivel up from lack of humidity. The goal is to create a "Goldilocks" environment: not too wet and not too dry.

There are several excellent materials you can use to pack your cannas:

• Peat Moss: This is a classic choice. It holds just enough moisture to keep the rhizomes from shriveling but is acidic enough to help discourage rot.
• Vermiculite or Perlite: These lightweight minerals are great for moisture control and provide excellent insulation.
• Wood Shavings or Sawdust: Often sold as pet bedding, these are inexpensive and effective. Avoid cedar shavings, as the oils can sometimes be too harsh for tender plants.
• Newspaper: If you prefer a simpler method, wrapping individual rhizomes in several layers of dry newspaper can work well.

Avoid using standard potting soil for storage. Potting soil often contains fertilizers or moisture-retaining crystals that are not helpful during dormancy. It can also stay too damp, which increases the risk of rot.

Packing Your Cannas for the Winter

Once your rhizomes are cured and your medium is ready, it is time to pack them away. You can use cardboard boxes, plastic bins with holes drilled for ventilation, or even breathable burlap sacks.

Start by placing a two-inch layer of your chosen storage medium at the bottom of the container. Place a layer of rhizomes on top, making sure they are not touching each other. Covering them with another layer of medium ensures that if one rhizome does start to rot, it won't immediately spread the problem to its neighbors.

Continue layering until the container is full, finishing with a final layer of packing material. If you are using plastic bins, remember that "breathability" is vital. Use a drill to pop several half-inch holes in the sides and lid of the bin. This allows just enough air exchange to prevent the buildup of gasses and condensation.

Storage Packing Checklist

• Labels inside and out: Place a tag inside the box and write the variety name on the outside of the box.
• Don't pack too tight: Ensure there is space for the packing material to surround each rhizome.
• Keep it breathable: Avoid airtight lids or sealed plastic bags, which trap moisture.

Finding the Perfect Storage Location

Where you put your packed cannas is just as important as how you pack them. The ideal storage location is cool, dark, and dry. You are looking for a temperature range between 40°F and 50°F.

If the temperature stays too warm (above 60°F), the cannas might try to wake up and start growing in the dark. This wastes their stored energy and results in weak, white, spindly sprouts. If the temperature drops below freezing (32°F), the rhizomes will die.

Common successful storage locations include:

• Unheated Basements: Usually the most consistent temperature for winter storage.
• Crawl Spaces: These often stay cool but protected from the worst of the winter chill.
• Root Cellars: The gold standard for dormant plant storage.
• Attached Garages: Be careful here; ensure the spot you choose doesn't drop below freezing during a cold snap.

Key Takeaway: A cool, dark basement is usually the best spot for cannas. Aim for a temperature that feels like a refrigerator’s "crisper" drawer—cool but never freezing.

Winter Check-ups: Monitoring Your Collection

Storing canna bulbs for winter is not a "set it and forget it" task. Even with perfect preparation, things can change over the three to five months they are in storage. We recommend checking on your rhizomes once a month throughout the winter.

Open your containers and feel a few of the rhizomes. They should feel firm and heavy for their size. If you find any that feel soft or mushy, remove them immediately and throw them away. Rot can spread quickly through a box if left unchecked.

If you find that the rhizomes are starting to look wrinkled or feel lightweight, they might be drying out too much. You can lightly mist the storage medium with a spray bottle filled with water. You don't want the medium to be "wet"—just a tiny bit of humidity is enough to plump the rhizomes back up. If you notice any mold or fuzzy growth on the surface, it means the medium is too damp. In this case, leave the lid off for a few days to let some moisture escape.

Managing Container-Grown Cannas

If you grow your cannas in large pots or decorative containers, you have a shortcut available to you. Instead of digging the rhizomes out of the soil, you can store the entire pot.

Once the frost has killed the foliage, cut the stalks back as you would for garden-grown plants. Move the entire container into a cool, dark, frost-free area like a basement or garage. Stop watering the pot completely. The soil will dry out, and the cannas will go dormant right where they are.

In the spring, you can simply move the pot back into the sun and start watering again. However, keep in mind that cannas grow very fast. After a year or two, the rhizomes will likely become "pot-bound," meaning they have filled every inch of the container. At that point, you will need to dump the pot out, divide the rhizomes, and replant them with fresh soil to keep the plants healthy and blooming well.

Bringing Cannas Out of Dormancy

As spring approaches and the threat of hard frost passes, you can start thinking about waking your cannas up. This usually happens about four to six weeks before your area’s last expected frost date.

When you unpack your rhizomes, they may already have small, pale nubs or "eyes" beginning to push out. This is a great sign that the plant is healthy and ready to grow. This is the ideal time to divide your clumps if you didn't do so in the fall. Use a clean, sharp knife to cut the rhizomes into sections. Each section must have at least one or two prominent eyes to grow into a successful plant.

You can give your cannas a head start by planting them in pots indoors. Use a high-quality potting mix and place the pots in a warm, sunny window. By the time the outdoor soil has warmed up to at least 60°F, you will have established plants ready to go into the ground. This "early start" method often results in earlier blooms, which is especially helpful for gardeners in northern climates with shorter summers.

Spring Re-entry Steps

• Inspect one last time: Discard anything that didn't make it through the winter.
• Divide with care: Ensure every piece has a growing point (an "eye").
• Wait for warm soil: Don't rush them into the garden. Cannas love heat and will sit and rot if the ground is too cold and wet in early spring.

Troubleshooting Common Storage Issues

Even experienced gardeners run into hurdles occasionally. The most common problem is rot, which is almost always caused by too much moisture or poor air circulation. If you consistently lose rhizomes to rot, try using a more breathable storage medium next year, like wood shavings or loosely wrapped newspaper.

Another common issue is desiccation, or the rhizomes drying out completely. This happens when the storage area is too dry or the packing material doesn't hold enough humidity. If your rhizomes feel like light, hollow sticks in the spring, they have likely dried out. Try checking them more frequently next winter and adding a tiny bit of moisture if they start to shrivel.

Finally, keep an eye out for "hitchhikers" like mice. Fleshy rhizomes can be a tempting winter snack for rodents. If you store your cannas in a garage or shed where mice are present, using plastic bins with small, screened ventilation holes can help protect your investment.

Why Storing Your Own Bulbs is Worth the Effort

While you can always buy new canna rhizomes each spring, there is a special satisfaction in seeing your own plants return year after year. Storing your bulbs allows you to keep rare or favorite colors that might not be available every season. It is also an incredibly cost-effective way to fill large garden beds.

Because cannas multiply so vigorously, you will likely find that you have more rhizomes in the spring than you dug up in the fall. This abundance allows you to expand your garden, fill more containers, or share the beauty of cannas with friends and neighbors. It’s a sustainable way to garden that connects you more deeply to the natural cycle of the seasons.

At Longfield Gardens, we believe that gardening should be a rewarding and accessible hobby. Taking the time to care for your plants through the winter is a small investment that pays off in a big way when those first tropical leaves unfurl in the summer sun.

Conclusion

Storing canna bulbs for winter is a simple and effective way to protect your favorite tropical plants from the cold. By following the natural cues of the first frost, carefully digging and curing the rhizomes, and providing a cool, stable environment for their dormancy, you ensure a vibrant garden for years to come. It is a process that turns a one-season plant into a lifelong garden companion.

• Wait for the first frost to signal dormancy before digging.
• Cure the rhizomes for several days to toughen the skin and prevent rot.
• Store in a cool, dark place between 40°F and 50°F using a medium like peat moss or wood shavings.
• Check monthly to ensure the rhizomes remain firm and healthy.

The effort you put in now will be rewarded with tall, lush stalks and brilliant flowers when the heat of summer returns. We are here to help you every step of the way as you grow a more beautiful and sustainable garden.

The secret to successful canna storage is finding the balance between moisture and air. With a little practice, you’ll be able to keep your collection growing and thriving for many seasons to come.

FAQ

Should I wash the dirt off canna rhizomes before storing them?

While you can wash them, it is not strictly necessary. Shaking off the loose soil is usually enough. If you do wash them, you must be very diligent about the curing process to ensure they are completely dry before you pack them away in a storage medium.

Can I store cannas in a refrigerator?

It is generally not recommended to store canna rhizomes in a kitchen refrigerator. Refrigerators are often too cold (below 40°F) and the air is very dry, which can cause the rhizomes to shrivel. Additionally, some fruits release gases that can interfere with the dormancy of the plants. If you need help planning spring shipping and planting timing, see our Shipping Information.

What happens if I forget to dig up my cannas until after the ground freezes?

If the ground has only frozen on the very surface, your rhizomes might still be okay. However, if the freeze has reached the depth of the rhizomes (usually 4–6 inches), they will likely turn to mush. It is always best to check them; if they are still firm and white inside, they may still be viable. For more zone guidance, review the Hardiness Zone Map.

Do I need to use fungicide on the rhizomes before storing them?

For the average home gardener, a fungicide is usually not necessary if the rhizomes are healthy and cured properly. If you have had significant issues with rot in the past, you can lightly dust the cut ends of divided rhizomes with sulfur powder to help prevent fungal growth. For more growing inspiration, read Fresh Ideas for Growing Cannas.