How to Prepare Canna Bulbs for Winter

Table of Contents

1. Introduction
2. Understanding Canna Rhizomes
3. When to Dig Your Cannas
4. Tools You Will Need
5. Step 1: Cutting Back the Foliage
6. Step 2: Digging the Rhizomes
7. Step 3: Cleaning and Rinsing
8. Step 4: The Curing Process
9. Step 5: Dividing the Rhizomes
10. Choosing the Best Storage Medium
11. Ideal Storage Conditions
12. Overwintering Cannas in Containers
13. Winter Check-ups: The Monthly Review
14. Winter Care by USDA Zone
15. Common Myths About Winterizing Cannas
16. Preparing for Spring: Waking Them Up
17. Growing Your Collection
18. Conclusion
19. FAQ

Introduction

Canna lilies bring a bold, tropical flair to the summer garden with their oversized leaves and vibrant, torch-like flowers. Watching these statuesque plants reach their peak in late summer is one of the most rewarding experiences for any gardener. While they look like they belong in a rainforest, they are surprisingly easy to manage even in colder climates. At Longfield Gardens, we want to help you keep that tropical magic alive year after year by showing you how to properly care for them when the seasons change.

Knowing how to prepare cannas for winter is the secret to enjoying a bigger and better display each spring. In most parts of the United States, cannas need a little extra attention to survive the freezing temperatures of winter. This process involves lifting the underground stems, known as rhizomes, and keeping them in a cozy, dormant state until the warm weather returns.

This guide will walk you through the simple steps of digging, cleaning, and storing your cannas. If you'd like a broader look at planning and growing these tropical favorites, see our All About Cannas guide. Whether you are a beginner or a seasoned gardener, you will find that overwintering these plants is a satisfying way to build your garden collection. By following a few basic steps, you can ensure your cannas stay healthy and ready to bloom again next summer.

Understanding Canna Rhizomes

Before you begin the winterization process, it helps to know exactly what you are working with. While many people refer to them as bulbs, cannas actually grow from rhizomes. A rhizome is a thick, fleshy underground stem that grows horizontally. These structures store the energy the plant needs to produce those massive leaves and bright flowers.

Because rhizomes are full of moisture and nutrients, they are sensitive to hard freezing. If the ground freezes solid around a canna rhizome, the water inside the cells expands and breaks the cell walls. This causes the rhizome to turn into mush once it thaws. In warmer climates, the soil stays warm enough to protect them. In colder regions, we simply move them to a place where the temperature stays above freezing.

Matching your winter care to your local environment is the first step toward success. Most gardeners find that cannas are very resilient. As long as you keep the rhizomes cool, dry, and away from frost, they will wait patiently for spring. This natural cycle of dormancy is actually quite beneficial for the plant, as it allows it to rest before the next big growth spurt.

When to Dig Your Cannas

Timing is everything when it came to preparing cannas for winter. You want to give the plant as much time as possible to store energy, but you must act before the ground freezes hard. The best signal to start the process is provided by nature itself: the first frost of autumn.

A light frost will usually turn the lush green or bronze canna leaves to a dark brown or black. While this might look disappointing at first, it is actually a helpful sign. This frost tells the plant that summer is over and it is time to go dormant. Once the foliage has been "zapped" by frost, the energy from the leaves moves down into the rhizome.

If you live in an area where frost comes very late, you can still dig them up in late autumn. Aim to do this once the weather consistently stays in the 40s at night. Digging them up while the leaves are still green is fine, but waiting for that first frost often makes the rhizomes easier to handle.

Key Takeaway: Wait for the first light frost to blacken the leaves. This is the plant's natural signal that it is ready for winter storage.

Tools You Will Need

Preparing cannas for winter does not require any specialized or expensive equipment. You likely already have everything you need in your garden shed. Having the right tools ready will make the job much faster and more enjoyable.

• Garden Fork or Shovel: A garden fork is often preferred because it is less likely to slice through the rhizomes.
• Pruning Shears or a Sharp Knife: You will need these to cut back the heavy stalks.
• Garden Hose: A gentle stream of water helps clean off stubborn soil.
• Storage Containers: Cardboard boxes, plastic bins with air holes, or paper bags all work well.
• Packing Material: Peat moss, vermiculite, wood shavings, or even shredded newspaper.
• Labels and a Marker: It is easy to forget which variety is which once the leaves are gone.

Step 1: Cutting Back the Foliage

The first physical step in the process is removing the top growth. After the frost has hit the leaves, the stalks will be soft and easy to cut. Use your pruning shears to cut the stems down to about 2 or 3 inches above the soil line.

Removing the bulk of the plant makes the digging process much easier. You won't have to fight with 6-foot tall stalks while trying to lift the roots. These short "stubs" also serve as a handy handle when you are lifting the clumps out of the ground. Don't worry about cutting them too short; the plant is dormant and won't be harmed.

Once the foliage is removed, you can add it to your compost pile, provided the plants were healthy and free of pests. If you noticed any unusual holes or signs of disease during the summer, it is better to dispose of the foliage in the trash to keep your garden clean for next year.

Step 2: Digging the Rhizomes

Now it is time to get into the soil. Canna rhizomes can spread quite a bit during a single growing season. A small rhizome planted in May can turn into a large, heavy clump by October. Because they grow horizontally, they are usually not very deep, but they can be wide.

Start by placing your garden fork or shovel about 8 to 12 inches away from the base of the stems. Pushing the tool in a bit further out helps ensure you don't accidentally spear the fleshy rhizomes. Gently pry upward to loosen the soil all the way around the plant.

Once the soil is loose, lift the entire clump out of the ground. If the clump is very large, you might need to lift it in sections. At this stage, do not worry if some of the rhizomes break apart naturally. This is normal and won't hurt the plant. Gently shake off the largest chunks of soil while you are still at the garden bed.

What to do next:

• Clear a space in your garage or shed for cleaning and drying.
• Check the rhizomes for any soft or mushy spots and set those aside.
• Keep different varieties in separate piles so you can label them later.
• Avoid leaving the lifted rhizomes out in the open if a hard freeze is expected overnight.

Step 3: Cleaning and Rinsing

Once the rhizomes are out of the ground, they will likely be covered in garden soil. While you don't need them to be perfectly "squeaky clean," removing the bulk of the dirt is important for a few reasons. First, it allows you to inspect the health of the rhizomes. Second, it prevents you from bringing garden pests or excess moisture into your indoor storage area.

Use your hands to gently brush away loose dirt. If your soil is heavy clay, you may find it easier to use a garden hose. Use a gentle spray to wash away the mud. Avoid using a high-pressure setting, as the skin of the rhizome can be somewhat tender when it first comes out of the ground.

You do not need to scrub the rhizomes. A simple rinse is enough. If you are working with many plants, placing them on a mesh screen or a piece of hardware cloth can make the rinsing process much faster. Once they are rinsed, let the excess water drain away before moving to the next step.

Step 4: The Curing Process

Curing is perhaps the most overlooked step in preparing cannas for winter, but it is one of the most important. Curing simply means allowing the rhizomes to air-dry in a protected spot for a few days. This process allows the "skin" of the rhizome to toughen up and any wounds from the digging process to callus over.

Place your cleaned rhizomes in a single layer on a piece of cardboard or a newspaper. A well-ventilated area like a garage, shed, or basement is perfect. Avoid placing them in direct sunlight or in a spot where they might get wet from rain.

The curing process usually takes between 3 and 7 days. You will know they are ready when the outer surface feels dry and firm to the touch. Curing significantly reduces the risk of rot during the long winter months. It is a simple "set it and forget it" step that makes a big difference in survival rates.

Step 5: Dividing the Rhizomes

After curing, you may want to divide your canna clumps. If you choose to divide them in the fall, see our How to Split Canna Bulbs guide. Cannas are very productive, and a single plant can often be divided into three or four new ones. You can do this now, or you can wait until spring.

If you choose to divide them in the fall, look for the "eyes." These are the small, rounded bumps on the rhizome where new growth will emerge. Each division should have at least two or three healthy eyes and a decent piece of the fleshy rhizome attached. You can usually snap them apart by hand, or use a clean, sharp knife for a more precise cut.

If you use a knife, some gardeners like to dust the cut ends with a bit of sulfur powder or cinnamon to prevent fungal issues. However, if you cured the rhizomes properly, the cuts should callus over naturally. Dividing in the fall saves space in your storage boxes, while dividing in the spring allows you to see exactly which parts of the plant are the most vigorous.

Choosing the Best Storage Medium

To keep canna rhizomes healthy through the winter, they need a environment that is "just right"—not too wet and not too dry. If the storage area is too damp, they will rot. If it is too dry, they will shrivel up and lose their vitality. Using a packing medium helps regulate this moisture.

• Peat Moss: This is the most popular choice. It holds a tiny bit of moisture but stays airy enough to prevent rot.
• Vermiculite or Perlite: These are lightweight minerals that provide excellent aeration.
• Wood Shavings: Often sold as pet bedding, these are inexpensive and work very well.
• Shredded Newspaper: A great budget-friendly option that most people have on hand.

Fill the bottom of your storage container with a few inches of your chosen medium. Place the rhizomes on top, making sure they aren't crowded or touching each other. Then, cover them with more of the medium until they are completely tucked in. This "nesting" protects them from temperature swings and keeps them from drying out too fast.

Ideal Storage Conditions

Where you put your boxes of cannas matters just as much as how you pack them. The goal is to keep them in a place that is cool and dark, but never freezing. The ideal temperature range for canna storage is between 40°F and 55°F.

A cool basement, an unheated crawl space, or a corner of an attached garage that stays above freezing are all excellent locations. Avoid placing them near a furnace, water heater, or any other heat source, as this will wake the plants up too early or dry them out.

Keep the boxes off the floor if possible, especially if your floor is concrete. Concrete can pull cold and moisture into the boxes. Placing them on a shelf or a wooden pallet is a safer bet. Also, make sure your storage containers have some ventilation. If you are using plastic bins, drill a few holes in the sides to let air circulate.

Key Takeaway: The "Golden Rule" of storage is 40-50°F in a dark, dry spot. If you stay in this range, your cannas will sleep soundly until spring.

Overwintering Cannas in Containers

If you grow your cannas in large pots or decorative containers, you have a bit of a shortcut. You don't necessarily have to dig them up. Instead, you can store the entire container. This is a great option for gardeners who only have a few plants or those who want to save time.

Once the first frost hits the foliage, cut the stalks down to the soil level just as you would for garden-grown plants. Move the entire pot into a frost-free area like a garage or basement. The soil in the pot will act as the storage medium, protecting the rhizomes from temperature changes.

The most important part of this method is to stop watering. The soil should be dry through the winter. If the soil stays wet in a cold garage, the rhizomes will likely rot. In early spring, you can bring the pot back into the light, give it a good drink of water, and watch the new shoots emerge.

Winter Check-ups: The Monthly Review

Gardening is a year-round activity, even when the plants are sleeping. It is a good idea to check on your stored canna rhizomes about once a month. This small effort allows you to catch any potential issues before they become problems.

Open your boxes and take a quick look. If you see any signs of rot—usually appearing as soft, fuzzy, or mushy spots—remove the affected rhizome immediately. This prevents the rot from spreading to the healthy plants. If a rhizome has just a small bad spot, you can often cut it away, let the healthy part dry for a day, and put it back in the box.

On the flip side, if the rhizomes look very shriveled or feel extremely light, they might be getting too dry. You can lightly mist the packing medium with a spray bottle of water. You don't want it to be wet, just slightly damp to the touch. This "re-hydration" helps the plant stay viable until planting time.

Winter Care by USDA Zone

Your approach to preparing canna bulbs for winter depends heavily on where you live. At Longfield Gardens, we recommend checking your USDA hardiness zone map to determine the best strategy for your yard.

• Zones 8 to 11: In these warmer regions, cannas are generally hardy. You can leave them in the ground all winter. It is still a good idea to cut back the dead foliage and apply a thick layer of mulch (about 4-6 inches) to protect the soil from occasional cold snaps.
• Zone 7: This is the "swing" zone. In mild winters, cannas may survive in the ground with heavy mulching, especially if they are planted near a warm south-facing wall. However, to be 100% safe, many gardeners in Zone 7 choose to lift and store at least a few of their favorite varieties.
• Zones 3 to 6: In these colder climates, lifting and storing is essential. The ground will freeze deep enough to destroy the rhizomes if they are left outside.

Regardless of your zone, remember that soil drainage plays a huge role. Rhizomes left in the ground are more likely to rot in cold, wet winter soil than in dry soil. If your garden tends to stay soggy in the winter, lifting them is a good idea even in warmer zones.

Common Myths About Winterizing Cannas

There are many "internet hacks" for storing bulbs, but simple is usually better. One common myth is that you must wash the rhizomes with bleach or harsh chemicals to prevent rot. This is usually unnecessary and can actually damage the living tissue of the plant. Clean water and a good curing period are all you need.

Another myth is that cannas need to be kept in total darkness. While a dark spot is ideal because it prevents the plants from sprout prematurely, a little bit of ambient light won't hurt them as long as the temperature stays cool. The temperature is much more important than the light level.

Lastly, some people believe you have to store them in plastic bags to "lock in" moisture. We advise against this. Plastic bags often trap too much moisture and don't allow for air exchange, which is a recipe for mold. Stick with breathable containers like cardboard or wooden crates.

Preparing for Spring: Waking Them Up

As the days get longer and the ground begins to thaw, you can start thinking about bringing your cannas out of storage. In most regions, this happens in late March or April. You don't have to wait until the last frost to start them indoors.

If you want an early start on the blooming season, you can "wake up" your rhizomes in pots about 4 to 6 weeks before the last frost date. For a step-by-step refresher, see our How to Start Planting Canna Bulbs Indoors guide. Plant them in potting soil, keep them in a warm, sunny window, and provide moderate water. By the time the weather is warm enough to plant them outside, you will already have several inches of healthy green growth.

If you prefer to plant directly into the garden, wait until the soil has warmed to at least 60°F and the danger of frost has passed. Cannas love warm soil and warm nights. Planting them too early in cold, wet ground will only result in slow growth. Patience in the spring pays off with rapid growth once the summer heat arrives.

Growing Your Collection

One of the best things about learning how to prepare canna bulbs for winter is how quickly your garden grows. Because cannas multiply so reliably, you will likely find yourself with more rhizomes than you started with every single year.

This abundance allows you to experiment with different parts of your landscape. You can create a massive tropical border with tall cannas, use them as a "living screen" for privacy, or feature them in large decorative containers. Surplus rhizomes also make wonderful gifts for friends and neighbors, spreading the joy of gardening throughout your community.

By taking the time to care for your plants over the winter, you are participating in a timeless gardening tradition. There is a special kind of satisfaction that comes from seeing a plant you saved yourself emerge from the soil in the spring, ready to put on a spectacular show once again.

Conclusion

Preparing canna bulbs for winter is a straightforward and rewarding process that preserves the beauty of your summer garden. By waiting for the first frost, carefully digging and cleaning the rhizomes, and providing a cool, dry place for them to rest, you ensure a vibrant display for the following year. Gardening is all about working with the seasons, and this simple autumn ritual is a great way to stay connected to your backyard landscape.

At Longfield Gardens, we believe that every gardener can find success with these tropical favorites, and our 100% Quality Guarantee helps back that up. The effort you put in now saves you money and gives you the satisfaction of seeing your plants grow larger and more beautiful with each passing season.

• Wait for a light frost to signal dormancy.
• Cure the rhizomes for several days before packing.
• Store in a cool, frost-free location (40-55°F).
• Check for moisture levels once a month during the winter.

We hope these tips help you feel confident in protecting your cannas. With just a little bit of preparation, your garden will be ready to burst into tropical color as soon as the summer sun returns.

FAQ

Do I have to wait for the frost to hit before I dig up my cannas?

While it isn't strictly mandatory, waiting for the first light frost is highly recommended. The frost acts as a natural signal for the plant to move its energy into the rhizomes and enter a dormant state. If you must dig them earlier due to travel or scheduling, try to wait until the weather is consistently cool in late autumn.

Can I store my canna rhizomes in the refrigerator?

It is generally not recommended to store canna rhizomes in a refrigerator used for food. Refrigerators are often too cold (usually around 35-38°F) and the lack of air circulation can lead to rot. Additionally, some fruits release ethylene gas which can interfere with the health of the dormant rhizomes. A cool basement or garage is a much better choice.

My rhizomes look shriveled and dry in the middle of winter, are they dead?

Not necessarily! It is normal for rhizomes to lose some moisture and look slightly wrinkled during dormancy. If they feel very light and "hollow," they may be too dry. Give the packing medium a light misting with water to add a touch of humidity, but do not soak them. Most of the time, they will plump back up once they are planted and watered in the spring.

What is the best material to pack canna bulbs in for the winter?

Peat moss and wood shavings are the top choices because they provide a good balance of moisture retention and air circulation. Both materials are easy to find and relatively inexpensive. If you don't have those, shredded newspaper or even dry sand can work well to keep the rhizomes separated and protected from temperature changes.

Creative Combinations

Canna foliage can inspire all sorts of wonderful plant combinations. In the second photo above, Tropicanna has been planted with coleus, amaranth, gaillardia, helianthus and lantana.

Tropicanna Gold brings the same eye-catching late summer display.

The colorful stripes on these cannas really glow when they’re backlit. In pots, they look terrific paired with coleus and anything with purple, pink or coral flowers.

To accentuate the drama of dark-leaved varieties such as ‘Australia’ and ‘Tropicanna Black’, pair them with the equally dark foliage of coleus, amaranth, alternathera or sweet potato vine. For dramatic contrast, add a splash of lime, creamy white or yellow.

Cannas for Hummingbirds

Want to attract hummingbirds to your garden? Plant cannas with bright red blossoms such as ‘Australia’, ‘Tropicanna Black’ and ‘Rosita’. They’ll keep hummers zooming through your garden all summer long.

Cannas always put on a great show — so why not put some of them to work in your garden this summer? You can shop our complete selection of varieties HERE. To learn more about planting and growing, read All About Cannas. Our in-house bulb expert, Hans Langeveld, also shows you how to plant them in this VIDEO.

Image: Cannas

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