Introduction
There is something truly spectacular about the way canna lilies transform a summer garden into a tropical paradise. With their bold, architectural foliage and vibrant, orchid-like blooms, they are the undisputed stars of the warm-weather landscape. At Longfield Gardens, we believe the joy of growing these exotic beauties shouldn't end when the temperature drops. Learning how to keep canna lily bulbs over winter is a simple and rewarding process that allows you to enjoy your favorite varieties year after year.
If you are looking for the fastest way to keep your plants alive, the core strategy is simple: unless you live in a very warm climate, you must protect the rhizomes from freezing. For most gardeners, this means lifting them from the soil in late autumn and storing them in a cool, dark, frost-free location until the ground warms up again in the spring.
This guide is designed for home gardeners who want to protect their investment and carry the lush beauty of summer into the next growing season. For a broader reference, see Winter Storage for Tender Bulbs and Tubers. We will cover everything from the best time to lift your plants to the specific storage techniques that keep them healthy during their dormant months. Whether you are a beginner or a seasoned gardener, you will find practical, step-by-step instructions to make overwintering a success.
By following a few basic steps, you can ensure that your canna lilies return with even more vigor next spring. Saving your own rhizomes is not only economical but also a wonderful way to build a personal collection of the plants you love most. If you'd like to expand your planting list, the Canna Assorted Collection is an easy place to start. Storing canna lily rhizomes is an easy gardening win that guarantees a head start on a beautiful garden next year.
Understanding Cannas and the Winter Season
Canna lilies are tropical and subtropical plants by nature. For a broader look at planning, planting, and growing, see All About Cannas. They thrive in heat and humidity, which is why they look so magnificent during the peak of summer. However, because they are native to warmer climates, they have not evolved to survive freezing soil temperatures. In most parts of the United States, the USDA Hardiness Zone Map shows why providing a bit of winter protection is necessary.
While gardeners often refer to the underground part of a canna lily as a "bulb," it is technically a rhizome. A rhizome is a thick, fleshy stem that grows horizontally under the soil. It acts as a storage tank for the plant, holding onto energy and nutrients that will fuel next year’s growth. Protecting this storage organ from the cold is the key to a successful spring bloom.
Climate-Based Decision Guide: To Dig or Not to Dig?
The first step in canna lily winter care is deciding whether your plants can stay in the ground or must be lifted. This decision depends on your USDA zone and your garden's specific conditions.
- Zones 8 to 11: Cannas are generally hardy here. You can keep them alive in the ground by simply cutting back the foliage and applying a 4-to-6-inch layer of mulch (such as straw or shredded leaves) to insulate the soil.
- Zone 7: This is the "borderline" zone. In many cases, cannas can survive a Zone 7 winter if they are planted in well-drained soil and protected by a heavy layer of mulch. However, if your winter is unusually wet or cold, they may rot. If you have a rare or favorite variety, we recommend digging it up to be safe.
- Zones 6 and Colder: The ground freezes deep enough to kill the rhizomes. To keep them alive, you must dig them up and store them indoors.
The Role of Microclimates
Even in colder zones, some gardeners find success leaving cannas in the ground due to microclimates. A protected bed against a south-facing brick wall or a spot near a heated foundation can stay several degrees warmer than the rest of the garden. If your soil is sandy and drains quickly, your cannas have a better survival rate than in heavy, wet clay, which often leads to winter rot.
Knowing When to Take Action
Timing is one of the most important factors when learning how to keep canna lily bulbs over winter. You want to give the plants as much time as possible to store energy, but you must act before the ground freezes solid. The ideal window for lifting cannas usually arrives in late autumn.
For many gardeners, the first light frost is the perfect signal. A light frost will cause the lush green leaves to turn brown or black, but it won't harm the rhizomes tucked safely underground. This change in the foliage tells the plant that it is time to go dormant. Once the leaves have withered, the plant stops active growth and focuses all its energy on its root system.
If you live in an area where a hard freeze might arrive suddenly, you can also lift your cannas before the first frost. While waiting for the frost is a traditional "nature-approved" signal, the plants will be just as healthy if you dig them up once the weather stays consistently chilly. The goal is to move them into storage while they are healthy and before the soil becomes too wet and cold, which can lead to rot.
Key Takeaway: Monitor the local weather forecast in late October or November. Once the foliage has been nipped by frost or the daytime temperatures no longer encourage growth, it is time to prepare for digging.
Preparing Your Cannas for Digging
Before you bring out the shovel, there are a few simple preparation steps that make the process much easier. Starting with a clean workspace and the right tools will protect both you and your plants.
Trimming the Foliage
The first step is to remove the spent top growth. Use a pair of sharp, clean garden shears or loppers to cut the stalks down to about 4 to 6 inches above the soil line. Leaving a short "handle" of the stem makes the rhizomes easier to handle and helps you identify which end is up. A clean cut is better than a jagged one, as it reduces the surface area where moisture or pests could enter the plant.
Gathering Your Tools
You don't need specialized equipment for this task. A sturdy garden spade or a garden fork is usually the best choice. A garden fork is particularly helpful because it allows you to loosen the soil around the rhizomes without the high risk of slicing through them. If you are working with cannas in containers, a smaller hand trowel may be all you need.
Clearing the Area
Remove any mulch, weeds, or fallen leaves from the base of the plant. This gives you a clear view of where the stems emerge from the ground. It also prevents old garden debris from getting mixed in with your storage medium later on.
How to Dig Canna Lily Rhizomes
Digging up cannas is a satisfying autumn task. Because the rhizomes grow horizontally and relatively close to the surface, they are generally easy to lift. The main goal is to remove the entire clump without bruising or breaking the fleshy structures.
Step 1: Loosen the Soil
Start by inserting your spade or fork into the ground about 8 to 12 inches away from the base of the stems. You want to give the root system plenty of space so you don't accidentally cut into the rhizomes. Push the tool deep into the soil and gently rock it back and forth to loosen the earth. Work your way in a circle all the way around the plant.
Step 2: Lift the Clump
Once the soil is loose, slide your tool underneath the center of the clump. Using the tool as a lever, gently lift the entire mass of soil and rhizomes out of the ground. If the clump is very large, you may need to lift it in sections, but try to keep the main structures intact for now.
Step 3: Remove Excess Soil
Pick up the clump and gently shake it to remove the large chunks of soil. You can use your hands to brush away more dirt, but be careful not to scrape the skin of the rhizomes. You don't need to get them perfectly clean yet; the most important thing is to get them out of the cold ground and into a protected space.
Cleaning, Curing, and Dividing Your Rhizomes
Once the rhizomes are out of the ground, they need a little bit of "spa time" before they go into long-term storage. This stage is vital for preventing rot and disease.
Initial Cleaning
Use your fingers to remove as much loose soil as possible. If the soil is very sticky or clay-like, you can use a soft-bristled brush to gently clean the crevices. Some gardeners prefer to rinse their rhizomes with a garden hose. While this makes them very clean, it also introduces a lot of moisture. If you choose to rinse them, you must be extra diligent during the drying phase. Most of the time, simply brushing off the dry soil is the safer and easier option.
Dividing and Identifying Viable Eyes
Winter is an excellent time to divide your canna clumps. Look for the "rhizome eyes"—these are the small, rounded bumps or points on the surface of the rhizome where new growth will emerge.
To divide, you can pull the clumps apart by hand or use a sharp, sterilized knife to cut them into smaller sections. A viable division should be firm and have at least one to three healthy eyes. If a section is very small or has no eyes, it is unlikely to grow and can be discarded. Dividing before storage can save space, but some gardeners prefer to wait until spring when the eyes are more prominent and active.
Inspecting for Health
Take a moment to look over each clump. Healthy canna rhizomes should feel firm and heavy, similar to a fresh potato. If you find any soft, mushy, or obviously damaged sections, trim them away with a clean knife. Removing these pieces now prevents decay from spreading to the healthy parts of the collection.
The Curing Process
Curing is simply the process of letting the rhizomes air-dry in a protected spot. Place your cleaned rhizomes in a single layer on a piece of cardboard, a wooden crate, or a screen. Keep them in a cool, dry place out of direct sunlight—an unheated garage, a shed, or a porch works well.
Let them dry for a few hours or even a couple of days. During this time, the "skin" of the rhizome will toughen up slightly, and any remaining soil will become easier to remove. This drying period ensures that you aren't trapping excess moisture inside your storage containers, which is the primary cause of winter rot.
Choosing a Storage Method
There are several effective ways to store canna lilies, and the best one for you depends on what materials you have on hand and how much space is available. Each method aims to keep the rhizomes dormant, cool, and slightly hydrated.
Comparison of Storage Media
The choice of packing material determines how well you balance moisture and airflow.
- Peat Moss: Excellent for moisture retention; helps prevent shriveling but can be dusty.
- Vermiculite or Perlite: Provides great aeration and is sterile, reducing the risk of mold.
- Wood Shavings or Sawdust: A low-cost option that provides good insulation, though very dry shavings may pull too much moisture from the rhizomes.
- Coconut Coir: A sustainable alternative to peat moss that holds moisture well and is easy to work with.
- Newspaper: The simplest and most breathable option, though it provides less moisture regulation than loose media.
The Packing Process
- Find a breathable container: Use a cardboard box, a wooden crate, or a plastic bin with several holes drilled in the sides for ventilation.
- Layer the media: Place a 2-inch layer of your chosen medium (slightly damp, like a wrung-out sponge) at the bottom.
- Arrange the rhizomes: Place them in a single layer so they aren't touching. This prevents rot from spreading if one piece fails.
- Cover and Repeat: Add more media until the rhizomes are covered. Finish with a final layer on top.
The Pot Storage Method
If you grow your cannas in containers, you have the easiest option of all. Once the foliage has died back, simply cut the stems down and move the entire pot—soil and all—into a frost-free area like a basement or crawl space. The soil in the pot acts as the storage medium. In the spring, you can tip the pot over, divide the rhizomes, and replant them in fresh soil. For another take on container growing, see the Summer Blooming Bulbs for Containers.
What to Do Next:
- Choose your storage container (cardboard boxes are often best for beginners).
- Select a storage medium (peat moss, sawdust, or newspaper).
- Label your containers with the variety name and flower color so you know what is what in the spring.
The Ideal Winter Environment
Location is everything when it comes to overwintering. You are looking for a spot that mimics a "refrigerator for plants"—cool enough to keep them asleep, but warm enough to prevent freezing.
The ideal temperature range for storing canna lilies is between 40°F and 50°F (4°C to 10°C). If the temperature stays above 60°F, the rhizomes may think it is spring and start to grow prematurely. If the temperature drops below 32°F, the water inside the fleshy rhizomes will freeze, causing the cells to burst and the plant to die.
Common successful storage locations include:
- Unheated Basements: Usually provide the most consistent temperatures.
- Attached Garages: Often stay just above freezing, but be careful of spots near outside doors.
- Crawl Spaces: These are naturally dark and cool, making them perfect for dormancy.
- Root Cellars: The traditional choice for storing bulbs and tubers.
Avoid storing your cannas near a furnace, water heater, or any other heat source, as these will dry out the rhizomes far too quickly. Similarly, keep them away from drafty windows where temperatures might fluctuate wildly.
Checking in and Troubleshooting
While your cannas are technically "sleeping," they still benefit from an occasional check-up. We recommend looking in on your stored rhizomes once a month throughout the winter.
Storage Troubleshooting and Rescue Steps
If you catch a problem early, you can often save the rest of your collection. Here is how to handle common storage issues:
- Shriveling and Wrinkling: This means the rhizomes are dehydrating. They should feel firm. If they look dry, use a spray bottle to lightly mist the storage medium. Do not pour water directly onto the rhizomes; you want to create a slightly humid environment, not a wet one.
- Soft Spots or Fuzzy Mold: This is a sign of too much moisture. Use a clean, sharp knife to cut away any mushy parts back to healthy, firm tissue. Dust the cut end with a little cinnamon (a natural antifungal) and let it dry for 24 hours before repacking in fresh, dry material.
- Early Sprouting: If you see white or pink "eyes" starting to grow in February or March, your storage area is likely too warm. Move the box to a cooler spot. If the sprouts are already several inches long, you may need to pot them up and grow them under lights until spring.
- Foul Odors: A rotting rhizome has a distinct, unpleasant smell. If you smell decay, unpack the box immediately and find the source. Remove the rotting piece and replace the surrounding storage media, as bacteria can spread quickly.
Waking Up Your Cannas in Spring
The excitement of a new gardening season begins when you see those first signs of life. As the days get longer and the danger of frost begins to fade, you can start the process of bringing your cannas out of dormancy.
In most regions, you can start your cannas indoors about 4 to 6 weeks before the last expected frost date. This "head start" is especially beneficial in northern climates where the growing season is shorter. Simply remove the rhizomes from their winter storage, inspect them one last time, and plant them in pots with fresh potting soil. For container-growing tips, see How to Grow Summer Bulbs in Containers.
Place the pots in a warm, sunny window or under grow lights. Once they feel the warmth and receive a bit of water, the "eyes" on the rhizomes will begin to swell and send up new green shoots. By the time the outdoor soil has warmed up to at least 60°F, you will have healthy, established plants ready to go into the garden.
At Longfield Gardens, we love this part of the process because it represents the transition from the quiet of winter to the vibrant energy of spring. Moving your home-grown cannas back into the garden is a rewarding milestone for any gardener.
Common Myths About Overwintering
There are a few common misconceptions about how to keep canna lily bulbs over winter that can lead to unnecessary stress. Clearing these up makes the process much more approachable.
First, many believe that if a rhizome breaks, it is ruined. This isn't true! Cannas are incredibly resilient. If a large rhizome snaps into two or three pieces during digging, each piece will likely grow into a full plant as long as it has at least one "eye" or growing point. In fact, many gardeners purposefully break them apart to increase their stock.
Second, some people think you must use chemical fungicides to keep them safe. While some professionals use these, they are usually not necessary for the home gardener. Providing the right temperature and moisture levels is much more effective than relying on sprays.
Finally, don't worry if your stored rhizomes don't look "pretty." They are underground stems, after all! As long as they are firm and free of widespread rot, they are ready to perform.
Success with Different Varieties
Different canna lily varieties may have slightly different rhizome sizes.
For instance, dwarf varieties like Crocosmia 'Lucifer' often have smaller, more compact rhizomes.
Tall, vigorous types like Canna Tall Australia produce much larger, sprawling clumps.
The same is true of Canna Tall Pretoria.
The storage method remains the same regardless of the size. However, larger rhizomes tend to be more resilient to drying out, while smaller ones may need a slightly more watchful eye during your monthly winter checks. No matter which variety you grow, the goal is always the same: keep them cool, dry, and dormant until the sun returns.
Transitioning from Storage to Garden
When it is finally time to plant outdoors, remember the rule of "right plant, right place." Cannas love full sun—at least six to eight hours of direct light a day. They also appreciate rich, well-draining soil and plenty of water during the heat of summer.
Wait until the soil is warm to the touch and there is no longer any risk of frost. Planting too early into cold, wet ground can cause the rhizomes to sit idly and potentially rot. Patience is rewarded with faster growth once the weather truly warms up. Dig a hole about 4 inches deep, lay the rhizome in horizontally with the eyes facing up, and cover with soil. Within a few weeks, you will see those familiar, tropical leaves pushing through the earth once again.
Key Takeaway: Success comes from matching the timing of your planting to the warmth of your local soil. A thermometer can help, but a good rule of thumb is to wait until you are comfortable wearing a light t-shirt outside for the majority of the day.
Conclusion
Overwintering canna lilies is one of the most practical and satisfying skills a gardener can master. By taking the time to lift and store these tropical treasures, you are participating in the full cycle of the garden's life. It transforms a one-season plant into a multi-year investment that grows in beauty and size every year.
At Longfield Gardens, we want every gardener to feel confident in their ability to maintain a stunning landscape. Remember that gardening is a journey, and each season brings new opportunities to learn and grow along with your plants. The steps are simple: dig after the frost, cure the rhizomes, store them in a cool and dry place, and check on them occasionally.
- Lift rhizomes after the first light frost kills the foliage.
- Cure them in a dry, protected area for a few hours to a day.
- Store in a breathable container with peat moss or newspaper.
- Keep the storage temperature between 40°F and 50°F.
- Check monthly for shriveling or rot.
Keeping your canna lilies safe through the winter is a bridge between the seasons. It turns the end of autumn into a promise for a lush, tropical summer to come.
We invite you to explore our selection of premium canna lilies and other summer-blooming bulbs to add even more color to your garden next year. Happy gardening!
FAQ
Do I really have to dig up my canna lilies if I live in a cold climate?
Yes, if you live in USDA Zone 7 or colder, the ground typically freezes deep enough to kill canna lily rhizomes. While some gardeners try to "over-winter" them with heavy mulch, lifting them and storing them in a frost-free area is the only way to guarantee they will survive a typical northern winter.
What is the best material to use for storing canna rhizomes?
Peat moss, vermiculite, and sawdust are the most popular choices because they provide a good balance of aeration and moisture retention. If you don't have those available, wrapping individual rhizomes in several layers of dry newspaper and placing them in a cardboard box is a very effective and low-cost alternative.
How often should I water my canna lilies while they are in storage?
You should not "water" them in the traditional sense, as too much moisture will cause them to rot. Instead, check them once a month; if the rhizomes look shriveled or the storage medium feels bone-dry, use a spray bottle to lightly mist the area with water just enough to keep them from drying out completely.
Can I store my cannas in the refrigerator?
While a refrigerator provides the right temperature, it is often too humid or too dry for long-term storage, and there is a risk of the rhizomes being affected by gases released by ripening fruit. It is much better to use a cool basement, crawl space, or an attached garage where temperatures stay between 40°F and 50°F.
