How to Store Canna Bulbs Over Winter Indoors

Table of Contents

1. Introduction
2. Understanding Canna Rhizomes
3. When to Bring Your Cannas Indoors
4. Preparing the Plants for Digging
5. How to Dig Canna Rhizomes
6. Cleaning and Curing Your Cannas
7. Choosing the Right Storage Medium
8. Containers for Winter Storage
9. Finding the Best Location for Storage
10. Checking Your Cannas During Winter
11. Storing Cannas Grown in Containers
12. Dividing Cannas in the Spring
13. Getting a Head Start on the Season
14. Common Myths About Canna Storage
15. Summary of the Overwintering Process
16. Practical Scenarios for Storage
17. Conclusion
18. FAQ

Introduction

Few plants bring the same tropical flair to a garden as cannas. Their oversized, lush leaves and vibrant, jewel-toned flowers make them a favorite for creating a backyard oasis. Whether you are growing tall varieties that reach six feet or dwarf types for a container, these plants are a summer highlight. At Longfield Gardens, we enjoy seeing how these striking plants transform a landscape into a lush retreat.

If you live in a region where winter temperatures drop below freezing, you may wonder how to save these beautiful plants for next year. While cannas are tropical in nature, they are quite easy to overwinter indoors. This process allows you to keep your favorite colors and even increase your plant collection over time. It is a rewarding way to transition your garden from one season to the next.

This guide will explain how to store canna bulbs over winter indoors with simple, practical steps. We will cover when to dig them, how to prepare them for their winter nap, and the best ways to keep them healthy until spring. By following this straightforward process, you can ensure your cannas return with even more vigor next summer.

Understanding Canna Rhizomes

Before we get started with storage, it is helpful to understand what we are actually digging up. While most gardeners call them "bulbs," cannas actually grow from rhizomes. A rhizome is a thick, fleshy underground stem that grows horizontally. These stems store energy for the plant and are the source of new growth in the spring.

When you look at a canna rhizome, you will see small bumps or points. These are called "eyes," and they are similar to the eyes on a potato. Each eye has the potential to become a new stalk. Over the course of a single summer, cannas are very productive. A single rhizome planted in May can grow into a large clump by October. This natural growth makes cannas a wonderful investment for your garden.

Storing these rhizomes is much like keeping a potato or an onion in a pantry. They need to stay dormant, which means they are resting and not actively growing. To stay dormant and healthy, they require a specific balance of temperature and moisture. If they get too cold, they will freeze and fail. If they stay too wet, they may rot. Our goal is to find the middle ground that keeps them plump and ready for spring.

When to Bring Your Cannas Indoors

Timing is everything when it involves overwintering tender plants. In many parts of the United States, cannas can stay in the ground until the first frost. In fact, a light frost can be quite helpful. When the temperatures dip and the foliage turns brown or black from the cold, it sends a clear signal to the plant. This signal tells the rhizome to stop growing and start storing energy for its dormant period.

Wait until a light frost has touched the leaves before you begin the digging process. If your area does not get frost until very late in the year, you can simply wait until the plants naturally begin to yellow or the weather turns consistently chilly. For most gardeners in colder zones, this usually happens in late October or November.

If you are expecting a very hard, deep freeze that will penetrate the soil, it is best to act quickly. While the rhizomes are protected by the earth, they should not be allowed to freeze. Once the tops of the plants have withered, you have a perfect window of time to get them safely inside.

Key Takeaway: The first light frost of autumn is your best indicator that it is time to dig up your cannas for winter storage.

Preparing the Plants for Digging

Before you reach for your shovel, you need to prepare the top of the plant. Cutting back the foliage makes the digging process much easier and cleaner. Use a sharp pair of garden shears or a bypass pruner to cut the stalks down. You should leave about 4 to 6 inches of stem above the soil line.

Leaving a small amount of stem gives you a "handle" to hold onto while you are moving the clumps. It also helps you see exactly where the base of the plant is located so you do not accidentally damage the rhizomes with your tools. Once the foliage is removed, you can add it to your compost pile or discard it.

If you have different varieties or colors of cannas, this is a great time to label them. You can tie a small tag around the base of the stems or write the variety name directly on the stem with a waterproof marker. This simple step ensures that when spring arrives, you will know exactly where to plant each color.

How to Dig Canna Rhizomes

When it is time to dig, the most important rule is to be gentle. Canna rhizomes are fleshy and can be easily bruised or cut. While they are resilient, any deep wounds can become an entry point for rot during the storage months. We want to lift them out of the ground as cleanly as possible.

1. Space your shovel correctly: Start digging about 8 to 12 inches away from the base of the stems. This distance helps ensure you do not slice through the rhizomes that have spread out during the summer.
2. Loosen the soil: Use a garden fork or a sturdy spade to gently lift the soil around the entire perimeter of the plant. Work your way around the clump, loosening it from different angles.
3. Lift the clump: Once the soil is loose, slide your tool underneath the center of the clump and pry it upward. Use your hands to help lift the heavy mass of rhizomes and soil out of the ground.
4. Shake off excess soil: Gently shake the clump or use your fingers to brush away large chunks of dirt. You do not need to get them perfectly clean yet, but removing the bulk of the garden soil makes them easier to handle.

If you find that the clump is too large to move at once, you can gently break it into smaller pieces. Cannas naturally want to divide, and you will often see where the different rhizomes are joined.

Cleaning and Curing Your Cannas

Once your cannas are out of the ground, they need a short period of preparation before they go into their final storage containers. This phase is often called "curing." Curing allows the outer skin of the rhizome to toughen up slightly and helps any excess moisture evaporate.

Some gardeners prefer to wash their cannas with a garden hose to remove all the soil. While this makes them very clean, it also adds a lot of moisture. If you choose to wash them, make sure they have plenty of time to dry completely. A simpler method is to let the soil dry for a day or two and then brush it off with a soft brush or your hands.

To cure your cannas, find a dry, frost-free spot like a garage, shed, or basement. Spread the rhizomes out in a single layer on a piece of cardboard or newspaper. Let them sit for two to three days. You want the surfaces to feel dry to the touch, but you do not want the rhizomes to shrivel up like raisins. If the weather is dry and mild, you can even do this outdoors in a shaded spot, but be sure to bring them in if rain or frost is in the forecast.

Key Takeaway: Curing your cannas for a few days in a dry spot helps prevent rot and prepares the rhizomes for several months of indoor storage.

Choosing the Right Storage Medium

The way you pack your cannas is one of the most important parts of the process. You want to create an environment that is "just right"—not too wet and not too dry. If the storage area is bone-dry, the rhizomes can dehydrate and lose their energy. If it is too damp, mold and rot can set in.

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

Peat Moss or Coco Coir

This is perhaps the most popular method. Peat moss and coco coir are excellent at holding just a tiny bit of moisture while still allowing the rhizomes to breathe. You can buy these at any garden center. Simply fill a container with a layer of the material, place your cannas on top, and cover them with more.

Wood Shavings or Sawdust

Pine shavings, like the kind used for animal bedding, are another great option. They provide excellent airflow and help cushion the rhizomes. These are very easy to find at farm supply stores and are generally very affordable.

Newspaper

If you want a simple and recycled option, newspaper works surprisingly well. You can wrap each individual rhizome clump in a few layers of newspaper and then stack them in a box. The paper acts as a buffer, soaking up excess humidity while preventing the rhizomes from drying out completely.

Vermiculite or Perlite

These lightweight mineral materials are often used in potting soil. They are very clean and do a good job of regulating moisture. They can be a bit more expensive than other options, but they are very effective at preventing rot.

Containers for Winter Storage

You have several choices when it involves the actual container for your cannas. Medium Cannas are especially useful if you prefer plants that are easy to manage in garden beds and containers.

• Cardboard boxes: These are inexpensive and naturally "breathable." They are one of the best choices for home storage.
• Plastic bins (without lids): You can use plastic totes, but leave the lids off or drill several large holes in the sides to allow air to move through.
• Milk crates or wooden baskets: These provide the best airflow and are easy to stack if you have a large collection.
• Paper bags: Large grocery bags can work for smaller quantities. Simply fill the bag with your storage medium and the rhizomes, then fold the top over loosely.

Finding the Best Location for Storage

Once your cannas are packed, they need a home for the winter. The ideal temperature for storing canna bulbs is between 45°F and 55°F. This temperature range is cool enough to keep them dormant but warm enough to prevent any risk of freezing.

Good locations include:

• An unheated basement that stays cool.
• A crawl space.
• A "cool closet" or a dark corner of a mudroom.
• An attached garage, provided it does not drop below freezing.

Avoid storing your cannas near a furnace, water heater, or any heat vents. The warmth will cause them to dry out too quickly or may even trick them into thinking it is spring, causing them to start growing in the dark.

It is also important to keep the storage area dark. Light can encourage the eyes on the rhizomes to begin sprouting prematurely. A dark, quiet corner is perfect for their winter rest.

Checking Your Cannas During Winter

Overwintering is not a "set it and forget it" task. To be successful, you should check on your canna rhizomes about once a month. This small effort can save your entire collection if an issue arises.

When you check your cannas, look for two things: rot and dehydration.

1. Check for rot: Gently feel a few of the rhizomes. They should feel firm, like a fresh potato. If you find any that feel soft, mushy, or have a foul smell, remove them immediately. If only a small part of a large clump is rotting, you can cut that part away and discard it. Removing affected pieces prevents the rot from spreading to the healthy rhizomes.
2. Check for dehydration: If the rhizomes feel very light or look shriveled, they may be getting too dry. You can lightly mist the storage medium (like the peat moss or wood shavings) with a spray bottle of water. Do not soak it; just add enough moisture to settle the dust. This small amount of humidity will help the rhizomes plump back up.

Action List: Monthly Winter Check-up

• Set a reminder on your calendar for the first of each month.
• Gently uncover a few rhizomes in each container.
• Feel for firmness and look for any signs of mold.
• Discard any soft or damaged pieces.
• Mist the packing material lightly if it feels bone-dry.

Storing Cannas Grown in Containers

If you grow your cannas in pots, you have a shortcut! Short Cannas can stay in the entire container.

After the first frost, cut the foliage back just as you would for in-ground plants. Move the pot into a cool, dark, frost-free location like a basement or garage. Stop watering the pot entirely. The soil will dry out, and the cannas will go dormant within the container.

In the spring, you can bring the pot back out into the sun, give it a good soak of water, and wait for the green shoots to appear. Every two or three years, you should still remove the cannas from the pot to divide them, as they will eventually become root-bound and run out of space.

Dividing Cannas in the Spring

One of the most exciting parts of growing cannas is how much they multiply. When you pull your cannas out of storage in the spring, you will likely find that your clumps are much larger than they were when you planted them. Spring is the perfect time to divide them and create more plants.

To divide your cannas, look for the "eyes" or growth points on the rhizomes. You can use a clean, sharp knife to cut the rhizomes into smaller pieces. Each piece should have at least two or three healthy eyes and a good portion of the fleshy stem.

After cutting, let the pieces sit in a dry spot for a day so the "wounds" can callow over (dry out). This protects them from rotting once they are back in the soil. At Longfield Gardens, we find that dividing cannas every spring keeps the plants vigorous and ensures you have plenty to share with friends and neighbors.

For more background on canna growth and care, see All About Cannas.

Getting a Head Start on the Season

Cannas love heat and can be a bit slow to wake up in the spring if the soil is cool. If you live in a northern climate with a short growing season, you can give your cannas a "head start" by starting them indoors about 4 to 6 weeks before the last frost date.

To do this, plant your divided rhizomes in pots filled with a high-quality potting mix. Place them in a warm, sunny window or under grow lights. Keep the soil slightly moist. By the time the weather is warm enough to plant them outside, you will already have several inches of green growth. This can result in flowers appearing much earlier in the summer.

If you prefer to plant them directly in the garden, wait until the soil is warm—ideally around 60°F—and there is no longer any danger of frost. Cannas are tropical plants, and they will grow much faster in warm soil than in cold, damp earth.

For more ideas on growing summer bulbs in pots, see Best Summer Bulbs for Containers.

Common Myths About Canna Storage

There are many tips online about how to store canna bulbs over winter indoors, but some can be misleading. Let’s clear up a few common misconceptions:

• Myth: You must wash them with bleach. While some people recommend a diluted bleach dip to kill fungus, it is usually unnecessary for home gardeners. If you dry your rhizomes properly and use a clean storage medium, they will stay healthy on their own.
• Myth: They must be stored in plastic bags. While plastic bags can work if they have plenty of air holes, they often trap too much moisture. Cardboard boxes or open bins are generally safer for beginners because they regulate humidity more naturally.
• Myth: You shouldn't divide them until you plant them. You can actually divide them in the fall or the spring. However, spring is often better because you can clearly see which "eyes" are the healthiest and most ready to grow.
• Myth: Cannas are too difficult for beginners. In reality, cannas are some of the toughest plants you can grow. Even if you make a small mistake in storage, these resilient rhizomes often bounce back beautifully.

Summary of the Overwintering Process

Successfully storing cannas is all about following a simple sequence of events. By mirroring the plant's natural life cycle, you can keep your garden favorites year after year.

"The secret to overwintering cannas is simple: wait for the frost, dig with care, and keep them cool and dry until spring."

Remember that gardening is a learning process. Every home has a slightly different environment, and you may find that your basement is drier than your neighbor's or your garage is a bit warmer. Pay attention to how your rhizomes look throughout the winter, and don't be afraid to make small adjustments.

Practical Scenarios for Storage

Sometimes, knowing the rules isn't enough; you need to see how they apply to your specific situation. Here are a few common scenarios gardeners face:

Scenario A: You have a small basement and a large collection. If space is tight, use the "newspaper wrap" method. By wrapping each clump in paper and stacking them in a single large cardboard box, you can store dozens of plants in a very small footprint. This also makes it easy to label each variety.

Scenario B: You live in a very dry climate. In places with low humidity, your rhizomes are more likely to shrivel. Using a plastic bin with holes drilled in the sides and packing them in damp (but not wet) peat moss will help retain the essential moisture they need to survive the winter.

Scenario C: You forgot to dig them and a hard frost hit. Don't panic! If the ground hasn't frozen solid, the rhizomes are likely still fine. Dig them up as soon as possible. The frozen foliage might be a bit slimier to handle, but the underground parts are often perfectly healthy. Get them inside, dry them off, and proceed with the curing process.

Conclusion

Overwintering your cannas is a satisfying way to wrap up the gardening season. It turns a one-time purchase into a lifelong collection and gives you a head start on a beautiful landscape for the following year. By waiting for the first frost, digging carefully, and providing a cool, dark home for the winter, you can enjoy these tropical beauties for many seasons to come.

At Longfield Gardens, we believe that gardening should be a rewarding and enjoyable experience for everyone. Taking the time to care for your rhizomes during the winter is a small investment that pays off in massive, colorful blooms all summer long. Our 100% Quality Guarantee helps gardeners shop with confidence.

• Wait for the first frost to signal dormancy.
• Cut back stalks to 6 inches and dig carefully to avoid bruising.
• Cure the rhizomes in a dry spot for 2–3 days.
• Store in a cool (45-55°F), dark place using peat moss or newspaper.
• Check monthly for rot or dehydration.

We look forward to helping you grow your most beautiful garden yet. With these simple storage steps, your cannas will be ready to shine again as soon as the warm weather returns.

FAQ

Can I store cannas in a refrigerator?

It is usually not recommended to store canna rhizomes in a kitchen refrigerator. Refrigerators are often too cold (usually around 35-40°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. A cool basement or garage is a much better environment.

What if my cannas start growing in the middle of winter?

If you see white or green sprouts appearing while the cannas are in storage, it usually means the storage area is too warm or getting too much light. Move the container to a cooler, darker spot to slow down the growth. If it is very close to spring, you can pot them up and grow them as houseplants until it is time to move them outside.

Do I have to dig up my cannas if I live in a warm climate?

If you live in USDA hardiness zone 8 or warmer, cannas can generally stay in the ground all year. In zone 7, they may survive with a thick layer of mulch (about 6-8 inches) to protect them from occasional deep freezes. However, if you want to be 100% sure they survive a record-breaking cold winter, or if you want to divide them, digging them up is still a good practice.

If you are unsure of your zone, check the Hardiness Zone Map.

Should I use a fungicide on the rhizomes before storing them?

For most home gardeners, a fungicide is not necessary. The best way to prevent fungus and rot is to ensure the rhizomes are properly cured (dried) before they go into storage and that the storage medium is not overly wet. If you have had significant problems with rot in the past, you can dust the rhizomes lightly with sulfur powder, which is a natural antifungal agent available at most garden centers.