Storing Canna Bulbs Over the Winter

Table of Contents

1. Introduction
2. Determining if You Need to Dig
3. When to Start the Process
4. Preparing the Plants for Digging
5. The Best Way to Dig Canna Rhizomes
6. Cleaning and Handling the Rhizomes
7. The Importance of Curing
8. Packing Your Cannas for Storage
9. Finding the Ideal Storage Location
10. Monitoring During the Winter
11. Overwintering Container-Grown Cannas
12. Dividing Your Cannas for Spring
13. Troubleshooting Common Issues
14. Preparing for Spring Planting
15. Conclusion
16. FAQ

Introduction

Few plants bring as much tropical flair and high-energy color to the garden as cannas. These majestic plants, with their paddle-shaped leaves and brilliant blooms, are a highlight of the summer landscape. At Longfield Gardens, we love how cannas transform a backyard into a lush oasis with very little effort. Their ability to thrive in the heat makes them a reliable favorite for gardeners across the country.

While cannas are tropical in nature, they are also incredibly resilient. In many parts of the United States, you can easily save these beautiful plants to enjoy again next year. Learning the simple steps for storing canna bulbs—which are technically called rhizomes—over the winter is a rewarding way to expand your garden. This process allows your collection to grow larger and more impressive each season.

This guide is designed for home gardeners who want a reliable, step-by-step method for overwintering their cannas. We will cover how to identify the right time to dig, the best ways to clean and cure your rhizomes, and how to keep them healthy until spring. By following these straightforward techniques, you can ensure your favorite varieties return to provide another summer of vibrant color.

Determining if You Need to Dig

The first step in winter care is understanding your local climate. Cannas are tropical perennials, meaning they are built for warmth and consistent sunshine. Whether or not you need to dig them up depends primarily on your USDA hardiness zone.

Cannas are generally hardy in zones 8 through 10. In these southern and coastal regions, the ground rarely freezes deep enough to damage the rhizomes. If you live in one of these areas, your cannas can usually stay in the ground all year. You might simply cut back the dead foliage after a frost and apply a layer of mulch to provide a little extra insulation for the winter months.

In zone 7, the situation depends more on your specific garden conditions. In a mild winter, cannas in zone 7 often survive just fine with a thick layer of straw or wood chips. However, if a particularly cold winter arrives, the rhizomes may suffer. Many gardeners in this zone choose to dig up a few of their favorite varieties just to be safe, while leaving others in the ground as an experiment.

For those of us in zones 6 and colder, digging is a necessary part of the yearly routine. In these regions, the frozen soil would cause the fleshy rhizomes to rot and die. While it might sound like a lot of work, the process is actually quite simple. Once you get the rhythm of the seasons down, digging cannas becomes a satisfying way to wrap up the gardening year.

Key Takeaway: Check your USDA zone first. If you are in zone 6 or colder, plan to dig your cannas. If you are in zone 8 or warmer, they can usually stay in the ground with a bit of mulch for protection.

When to Start the Process

Timing is one of the most important factors when storing canna bulbs over the winter. 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 freezes solid.

The best signal comes directly from nature: the first light frost. When a light frost hits, the foliage of your cannas will turn black or brown and begin to wilt. This is not a sign of failure; it is actually a helpful signal. The frost tells the plant that the growing season is over and it is time to go dormant. This dormancy is essential for a successful storage period.

It is best to wait for this first frost before you start digging. The leaves continue to send energy down into the rhizomes right up until they are killed by the cold. This extra energy helps the plant sprout more vigorously the following spring. However, you should not wait for a "hard freeze," which is when the ground itself begins to freeze. A light surface frost that kills the leaves is perfect, but you want to dig the rhizomes while the soil is still easy to work with.

If you live in an area where frost comes very late or not at all, you can still dig your cannas once the days get short and the plants naturally begin to yellow. Most gardeners aim to have their cannas out of the ground by late October or early November, depending on the local weather.

Preparing the Plants for Digging

Once the foliage has been hit by frost, you can begin the preparation. Start by cutting the stalks back. Use a clean pair of garden shears or a sharp knife to cut the stems down to about 2 to 4 inches above the soil line. For broader planting and care tips, see our How to Grow and Care for Canna Bulbs.

Leaving a few inches of stem serves two purposes. First, it gives you a "handle" to hold onto while you are cleaning the rhizomes. Second, it helps you identify which way is up when you go to replant them in the spring.

After cutting the foliage, clear away any mulch or debris from the base of the plants. This makes it easier to see exactly where the rhizomes are located so you do not accidentally slice through them with your shovel.

• Wait for the first frost: This signals the plant to go dormant.
• Cut back foliage: Leave 2–4 inches of stem above the soil.
• Clear the area: Remove mulch to see the base of the plant clearly.

The Best Way to Dig Canna Rhizomes

Digging cannas requires a gentle touch. Canna rhizomes are fleshy and can be easily bruised or cut. Any wound on the rhizome is a potential entry point for rot during the long winter months.

It is best to use a garden fork or a sturdy spade for this task. Start by digging a circle around the entire clump of plants. You should stay at least 6 to 10 inches away from the main stems. This ensures you are outside the main mass of rhizomes.

Gently push your tool into the soil and lean back to lift the entire clump upward. If the clump is large and heavy, you may need to work your way around the circle, lifting slightly from different angles until the whole mass feels loose. Once the soil is loose, lift the clump out of the ground.

Do not be surprised by the size of the root mass. A single canna rhizome planted in May can easily grow into a massive clump by October. This is one of the best parts of growing cannas—they naturally multiply, giving you more plants every single year.

Cleaning and Handling the Rhizomes

Once the clumps are out of the ground, you need to remove the excess soil. Most of the soil will fall away if you gently shake the clump or crumble it with your hands. For any stubborn soil stuck in the crevices, you can use a soft brush or a light spray from a garden hose.

If you use a hose, be careful not to use high pressure. You want to wash the dirt away, not peel the skin off the rhizomes. If you do wash them, it is even more important to ensure they are dried thoroughly during the curing stage.

After cleaning, take a close look at the rhizomes. You are looking for firm, healthy structures. If you see any soft spots, shriveled sections, or areas that look like they are already rotting, use a clean knife to trim those parts away. If you want a closer look at healthy storage pieces, here’s what a canna bulb looks like. Healthy rhizomes should feel heavy for their size and firm to the touch, similar to a fresh potato.

Key Takeaway: Work slowly and lift the entire clump at once. Avoid poking or slicing the fleshy rhizomes, as intact skins are the best defense against winter rot.

The Importance of Curing

Curing is a step that many new gardeners skip, but it is vital for long-term success. Curing is simply the process of letting the rhizomes air-dry in a protected spot for a few days before you pack them away.

This drying period allows the "skin" of the rhizome to toughen up. It also helps any small nicks or cuts from the digging process to callus over, which prevents moisture loss and blocks out disease.

To cure your cannas, find a dry, well-ventilated area that stays out of direct sunlight. A garage, a shed, or a covered porch works well. Lay the rhizomes out in a single layer on a piece of cardboard or newspaper. Do not stack them, as you want air to reach all sides of the plant.

Let them sit for about 7 to 10 days. The goal is to have the exterior feel dry and the remaining bits of soil turn into a dry powder. If the weather is particularly humid, you might need an extra few days. Once the curing is complete, you can trim off any long, thin roots that are hanging off the main rhizome, as these will just dry up and fall off anyway.

Packing Your Cannas for Storage

The goal of storage is to keep the rhizomes in a state of suspended animation. You want them to stay cool enough that they do not start growing, but warm enough that they do not freeze. You also need to manage moisture: if they are too wet, they will rot; if they are too dry, they will shrivel up and die.

There are several effective ways to pack cannas. The most popular method is using a storage medium that regulates moisture.

Using Peat Moss or Vermiculite

Peat moss and vermiculite are excellent because they are sterile and hold just the right amount of ambient moisture. Place a layer of the medium in the bottom of a cardboard box or a plastic bin with holes drilled in the sides for airflow. Place the rhizomes in the box so they are not touching each other, then cover them with more peat moss or vermiculite.

The Newspaper Wrap

If you do not have peat moss, common newspaper is a great alternative. Wrap each individual rhizome or small clump in a few layers of dry newspaper. This provides a barrier between the plants and helps absorb any excess moisture that might lead to rot. Once wrapped, place them in a cardboard box.

Plastic Bags with Ventilation

Some gardeners have success using plastic grocery bags. If you use this method, add a handful of dry peat moss or wood shavings to the bag and make sure there are several holes in the plastic. Never seal the bag completely, as the rhizomes are living things that need a tiny bit of oxygen to stay healthy.

• Choose a container: Cardboard boxes, crates, or bins with air holes.
• Select a medium: Dry peat moss, vermiculite, or newspaper.
• Spacing: Avoid letting rhizomes touch each other to prevent the spread of potential rot.

Finding the Ideal Storage Location

Location is everything when it comes to overwintering. You are looking for a spot that is "cool and dark." The ideal temperature range is between 45°F and 55°F.

If the temperature stays above 60°F for too long, the cannas might think it is spring and start to sprout prematurely. If the temperature drops below 40°F, you risk the rhizomes being damaged by the cold.

Typical storage spots include:

• Unheated Basements: Often provide the most stable temperatures.
• Root Cellars: The traditional choice for storing bulbs and tubers.
• Attached Garages: Can work well, but be careful that the box doesn't sit directly on a freezing concrete floor. Place the box on a shelf or a piece of wood.
• Crawl Spaces: Usually stay cool and out of the way.

Avoid storing cannas near a furnace or water heater, as the heat and dry air will quickly dehydrate the plants.

Monitoring During the Winter

Storing canna bulbs over the winter is not a "set it and forget it" task. It is a good idea to check on your box of rhizomes once a month.

When you check them, look for two things: rot and shriveling. If you find a rhizome that has turned soft or mushy, remove it immediately. Rot can spread from one plant to another, so catching it early is the best way to save the rest of your collection.

If the rhizomes look very shriveled and feel light, they are getting too dry. You can fix this by lightly misting the storage medium (the peat moss or newspaper) with a spray bottle of water. You don't want the medium to be "wet"—just a tiny bit of moisture is enough to stop the dehydration process. Most of the time, if you have packed them correctly, they will stay perfectly firm until spring.

Overwintering Container-Grown Cannas

If you grow your cannas in large pots or decorative containers, you have a shortcut available. If you want a container-friendly option to compare, take a look at Canna Medium Banana Punch. You don't necessarily have to dig the rhizomes out of the soil.

After the first frost kills the foliage, cut the stems back to the soil level just as you would for garden-grown plants. Instead of digging, simply move the entire pot into a frost-free location like a basement or garage.

The dry soil in the pot acts as a natural storage medium. You do not need to water the pot at all during the winter. In fact, keeping the soil dry is what keeps the plant dormant. In the spring, you can bring the pot back outside, give it a good soak with water, and the cannas will begin to grow again. Every few years, you will still need to empty the pot to divide the rhizomes, as they will eventually become "root-bound" and run out of space.

Key Takeaway: Containers can be moved indoors as-is. This is a great time-saver for patio gardeners, provided you have the space to store the entire pot in a cool, dark area.

Dividing Your Cannas for Spring

One of the most exciting parts of storing canna bulbs over the winter is the multiplication factor. By the time spring arrives, you will likely have many more "growing points" than you started with.

In late March or early April, you can take your rhizomes out of storage and prepare them for planting. This is the best time to divide them. Look for the "eyes" on the rhizome—these are the small, pointed bumps where the new stems will grow.

Using a clean, sharp knife, you can cut the large clumps into smaller sections. Each section should have at least two or three healthy eyes. Let the cut pieces sit for a day or two so the "wounds" can dry out before you put them back into the soil.

This division process is how we at Longfield Gardens recommend building a massive display of color over a few seasons. For a fuller look at bold summer plantings, browse Tall Cannas. Starting with just a few plants can lead to dozens of blooms in just a couple of years if you divide them each spring.

Troubleshooting Common Issues

While storing canna bulbs over the winter is generally very successful, you might run into a few minor hurdles. The most common issue is the rhizomes drying out too much. If they look like raisins, they have lost too much water. You can often save these by soaking them in a bucket of lukewarm water for a few hours before planting in the spring.

Another issue is "waking up" too early. If your storage area gets a sudden warm spell in February, you might see pale white sprouts appearing. If this happens, try to move the box to an even cooler spot to slow them down. If the sprouts are already several inches long, you might want to pot them up and grow them as temporary houseplants near a sunny window until the weather warms up outside.

Finally, if you find that your cannas didn't bloom well the previous year, it might be that they were too crowded. Spring division solves this problem by giving each plant more room to breathe and more access to nutrients in the soil.

Preparing for Spring Planting

When the threat of frost has passed and the soil has warmed up to at least 60°F, it is time to bring your cannas back to the garden. For a step-by-step planting refresher, see How to Plant Canna Bulbs for a Stunning Tropical Garden. This is usually around the same time you would plant tomatoes or other warm-season vegetables.

Choose a spot with full sun—at least six hours of direct light is best for the biggest blooms. Cannas love rich soil and plenty of moisture, so adding a bit of compost to the planting hole is a great way to welcome them back. Plant the rhizomes about 4 to 6 inches deep, with the "eyes" facing upward.

Within a few weeks, you will see the first green shoots poking through the soil. Because you took the time to store them correctly over the winter, these plants will have a head start and will quickly grow into the towering, colorful beauties you remember from the previous summer.

Conclusion

Storing canna bulbs over the winter is a simple and rewarding practice that allows you to preserve your favorite garden varieties year after year. By waiting for the first frost, curing the rhizomes properly, and finding a cool, dark spot for their winter nap, you ensure a spectacular show of tropical color every summer. This process not only saves money but also gives you the satisfaction of watching your garden grow and multiply over time.

At Longfield Gardens, we want every gardener to feel confident in their ability to maintain a beautiful, thriving landscape. If you want to explore more options, our Canna Assorted Mix - Bulk Offer is a great way to build a colorful planting. Overwintering tender plants like cannas is a great way to deepen your connection to the rhythms of the seasons.

• Wait for the frost to signal dormancy.
• Cure the rhizomes for at least a week before packing.
• Store in a cool, dry place between 45°F and 55°F.
• Check monthly for rot or dehydration.

"The effort you put into protecting your cannas during the winter pays off in spades when those first lush, tropical leaves emerge in the spring heat."

We invite you to explore our selection of premium canna varieties to find the perfect colors for your garden. With just a little bit of winter care, these plants will remain a focal point of your backyard for many seasons to come. For extra inspiration, browse Canna Tall Australia.

FAQ

Can I leave my cannas in the ground if I live in Zone 7?

In Zone 7, cannas can often survive the winter if the ground does not freeze deeply. To improve their chances, cut the foliage back after the first frost and apply 6 to 8 inches of mulch, such as straw or wood chips, to insulate the soil. However, if a severe or prolonged cold snap is predicted, digging them up is the only way to guarantee their survival.

Do I have to wash the dirt off the rhizomes before storing them?

While you don't have to wash them, removing excess soil helps prevent moisture from being trapped against the rhizome, which can cause rot. Most gardeners find that shaking or brushing off the loose soil is enough. If you do choose to wash them with a hose, you must be very diligent about the curing process to ensure they are completely dry before they go into storage boxes.

What should I do if my stored canna rhizomes feel soft?

A soft or mushy rhizome is a sign of rot and should be removed from your storage container immediately to prevent the spread of disease to healthy plants. If only a small part of a large clump is soft, you can try cutting away the rotten portion with a clean knife until you reach firm, white flesh. Let the cut area dry and callus for a few days before returning the healthy portion to storage.

Why did my canna bulbs shrivel up during the winter?

Shriveling occurs when the storage environment is too dry or the rhizomes weren't packed with enough protective material. Canna rhizomes are fleshy and hold a lot of water; if they lose too much, they become dehydrated. If you notice shriveling during your monthly check, lightly mist the packing medium with water to add a small amount of humidity back into the box.