Table of Contents
- Introduction
- Understanding Canna Lilies and Winter Dormancy
- Determining Your USDA Hardiness Zone
- When to Start the Winterizing Process
- Step 1: Cutting Back the Foliage
- Step 2: Digging Up the Rhizomes
- Step 3: Cleaning and Inspecting the Roots
- Step 4: Curing the Rhizomes
- Step 5: Choosing the Right Storage Container
- Step 6: Using Storage Media
- The Ideal Storage Environment
- Winter Maintenance and Monitoring
- Special Case: Winterizing Cannas in Pots
- Transitioning to Spring
- Conclusion
- FAQ
Introduction
Canna lilies bring an unmistakable tropical flair to any landscape with their towering height, broad foliage, and brilliant blooms. These sun-loving plants are a highlight of the summer garden, often blooming well into the autumn months. For a quick shopping start, browse our cannas selection.
At Longfield Gardens, we enjoy helping you get the most out of your garden by sharing practical tips for plant care. Winterizing your cannas is one of the most effective ways to build a bigger, more beautiful display over time. If you want a ready-made mix, see Assorted Cannas.
This guide will walk you through the entire process of lifting, cleaning, and storing your canna rhizomes. Whether you are a beginner or an experienced gardener, you will find that winterizing is a straightforward task that preserves your investment and ensures a vibrant garden next season. For mid-size options, browse Medium Cannas.
Saving your cannas is an easy win that turns a single season of color into a lifetime of summer beauty.
Understanding Canna Lilies and Winter Dormancy
Before we dive into the "how-to," it is helpful to understand what a canna lily actually is. Although we often call them "bulbs," cannas grow from rhizomes. For a taller showpiece, take a look at Tall Cannas. A rhizome is a thick, fleshy underground stem that stores energy for the plant. During the summer, the rhizome uses this stored energy to push out those massive leaves and bright flowers.
As the weather cools, the plant begins to shift its energy back down into the rhizome. This is a natural preparation for dormancy. In their native tropical climates, cannas might grow all year round. However, in most parts of the United States, the freezing temperatures of winter would turn the water-heavy rhizomes into mush if left unprotected.
Winterizing is simply the process of helping the plant complete its dormancy in a safe, frost-free environment. By lifting them from the ground, you are protecting the energy the plant has worked hard to store all summer. When you replant them in the spring, that stored energy gives them a head start, resulting in faster growth and earlier blooms.
Determining Your USDA Hardiness Zone
The first step in winterizing is knowing if you actually need to dig your plants up. The Hardiness Zone Map is the standard for determining which plants can survive the winter in your specific location.
If you live in zones 8, 9, or 10, your cannas can usually stay in the ground year-round. In these warmer climates, the soil rarely freezes deep enough to damage the rhizomes. A thick layer of mulch—about 4 to 6 inches of straw, shredded leaves, or wood chips—is often enough to protect them through the occasional cold snap.
If you live in zone 7, you are in a "swing" area. In mild winters, cannas may survive with heavy mulching. However, a particularly harsh winter or a wet, cold spring can cause them to rot. Many gardeners in zone 7 choose to dig up their prized varieties just to be safe.
For those in zones 3 through 6, winterizing is a must. In these regions, the ground freezes solid, which will unfortunately kill the tropical rhizomes. Knowing your zone helps you plan your autumn garden chores so you aren't caught off guard by the first hard freeze.
Key Takeaway: Cannas are tropical plants that cannot survive frozen soil. If you live in zone 7 or colder, plan to lift and store your rhizomes to ensure they return next year.
When to Start the Winterizing Process
Timing is everything when it comes to winterizing cannas. You want to give the plant as much time as possible to store energy, but you must act before the ground freezes. For timing details, see When Do I Dig Up Canna Lily Bulbs?.
The best signal to start is the first light frost. You will notice that after a night of freezing temperatures, the lush green foliage of your cannas will turn black or brown and look wilted. This may look a bit sad, but it is actually a good thing. The frost sends a chemical signal to the rhizome that it is time to go to sleep.
Once the foliage has been "zapped" by the frost, wait a few days to a week before digging. This short waiting period allows the last bit of energy to move from the stalks down into the roots. If you live in an area where frost comes very late, you can still dig them up in late autumn (usually late October or early November) even if a frost hasn't occurred yet.
What to do next:
- Monitor your local weather forecast for the first frost warning.
- Observe the leaves; once they turn dark and collapse, the plant is ready.
- Gather your tools: a garden fork or spade, pruning shears, and storage containers.
Step 1: Cutting Back the Foliage
Before you reach for the shovel, you need to clear away the top growth. This makes the digging process much easier and keeps your workspace tidy.
Using a sharp pair of pruning shears or a garden knife, cut the stalks down so they are only 2 to 4 inches above the soil line. These short "stubs" will act as convenient handles when you are lifting the heavy root clumps later.
Do not worry about being too precise with the cut. The goal is simply to remove the bulk of the foliage. You can add the healthy green or blackened leaves to your compost pile, provided they aren't showing signs of disease or pests. Clearing the area first allows you to see exactly where the base of the plant is, which helps prevent accidental damage during the digging phase.
Step 2: Digging Up the Rhizomes
Cannas are vigorous growers, and by the end of the summer, a single rhizome can turn into a large, heavy clump. To lift them safely, you want to avoid cutting into the fleshy roots.
Start by digging a circle around the plant, about 8 to 12 inches away from the stalks. Use a garden fork if possible, as the tines are less likely to slice through a rhizome than a flat shovel blade. Sink the fork deep into the soil and gently pry upward, working your way around the entire clump.
Once the soil is loosened, you can usually lift the whole mass out of the ground by grasping the remaining leaf stubs. If the clump is very large, don't be afraid to break it into a couple of pieces to make it manageable. Canna rhizomes are quite tough, but you should still handle them with care to avoid deep bruises or gashes that could lead to rot during storage.
Step 3: Cleaning and Inspecting the Roots
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 clean, removing the bulk of the dirt is important for a healthy storage environment.
Shaking Off the Soil
Gently shake the clump to knock off loose clods of dirt. You can use your hands to brush away soil from the crevices. Some gardeners prefer to use a garden hose to wash the rhizomes clean. This is fine, but if you wash them, you must be extra diligent about the drying (curing) phase that follows.
Inspecting for Health
Take a moment to look at each rhizome. A healthy canna rhizome should feel firm, like a fresh potato. If you find any parts that are soft, mushy, or smell bad, trim those sections away with a clean knife. Healthy rhizomes are usually white, tan, or pinkish on the inside.
Dividing (Optional)
If your canna clumps have grown too large for your storage boxes, you can divide them now. Simply snap or cut the rhizomes into sections. Ensure each section has at least one or two "eyes"—these are the small, rounded bumps where next year’s growth will emerge. If you make fresh cuts, you can dust them with an organic fungicide or wood ash to help them calluse over, though this isn't strictly necessary if your storage conditions are good.
Step 4: Curing the Rhizomes
Curing is perhaps the most overlooked step in how you winterize canna lily bulbs, but it is vital for success. Curing is the process of letting the outer skin of the rhizome dry and toughen up before it goes into storage. For a fuller walkthrough, read Storing Canna Lily Bulbs Over Winter.
Place your cleaned rhizomes in a dry, well-ventilated area that is protected from frost and direct sunlight. A garage, a shed, or even a covered porch works well. Spread them out in a single layer on a piece of cardboard or a newspaper.
Let them sit for about 3 to 7 days. During this time, any remaining moisture on the surface will evaporate, and the cut ends will begin to dry out. This "tough skin" acts as a natural barrier against mold and rot while the plant is dormant. If the weather is particularly damp, you might need the full week; if it is very dry, three days may be enough.
Key Takeaway: Never rush the curing process. Ensuring the surface of the rhizome is dry to the touch is the best way to prevent rot during the long winter months.
Step 5: Choosing the Right Storage Container
How you pack your cannas depends on the space you have and your local humidity levels. The goal is to keep the rhizomes cool and dark while maintaining just enough moisture so they don't shrivel up completely.
Cardboard Boxes
Cardboard is an excellent choice because it "breathes." It allows for a tiny bit of air exchange while keeping the light out. You can line the box with a few layers of newspaper for extra insulation.
Plastic Bins
If you use plastic storage bins, do not put the lid on tight. Plastic traps moisture, which can lead to a moldy mess. If you prefer bins, drill several large holes in the sides and lid to ensure plenty of airflow, or leave the lid slightly ajar.
Paper Bags
For smaller quantities, heavy-duty paper grocery bags work well. You can place a few rhizomes in each bag with some packing material and fold the top over loosely.
Step 6: Using Storage Media
You shouldn't just toss the rhizomes into a box by themselves. Using a "storage medium" helps regulate moisture and prevents the rhizomes from touching each other, which stops any potential rot from spreading.
Some of the best materials to use include:
- Peat Moss: This is the most popular choice. It is sterile and holds a tiny bit of moisture without being "wet."
- Vermiculite: A mineral that is excellent for moisture control.
- Shredded Paper: A great budget-friendly option that provides good insulation.
- Wood Shavings: Often sold as pet bedding, these are dry and allow for good airflow.
To pack them, put a 2-inch layer of your chosen material in the bottom of the container. Place a layer of rhizomes on top, making sure they don't touch each other. Cover them with more material and repeat the process until the box is full. Finish with a final layer of packing material on top.
What to do next:
- Label your boxes with the variety name and the date.
- Choose a storage medium that is slightly damp but not wet—it should feel like a well-wrung-out sponge.
- Place the containers in their final winter home.
The Ideal Storage Environment
Now that your cannas are packed, they need a place to "sleep." The perfect storage spot is cool, dark, and dry. For a more complete seasonal overview, see How to Care for Canna Bulbs.
The ideal temperature range is between 40°F and 50°F. If the temperature stays in this range, the rhizomes will remain dormant. If it gets much warmer (above 55°F), they might think it is spring and start to sprout prematurely. If it drops below freezing (32°F), the rhizomes will be damaged.
Common storage locations include:
- An unheated (but attached) garage.
- A cool basement or cellar.
- A crawl space.
- A closet located on an outside wall of a cool room.
Avoid placing your boxes near a furnace, water heater, or any heat vents. The dry, warm air from a heating system will shrivel the rhizomes very quickly.
Winter Maintenance and Monitoring
Winterizing isn't a "set it and forget it" task. To ensure a high survival rate, it is a good idea to check on your cannas about once a month. This only takes a few minutes but can save your entire collection.
Open the boxes and peek at a few rhizomes. If you see any that have turned soft or show fuzzy white mold, remove them immediately. This prevents the problem from spreading to the healthy ones. If the rhizomes look very shriveled and feel lightweight, the storage medium might be too dry. In this case, use a spray bottle to lightly mist the packing material with water. Do not soak it—just a little moisture is enough to plump them back up.
Most experienced gardeners are very happy if 80% to 90% of their stored rhizomes make it through the winter. Don't be discouraged if you lose one or two; it is a normal part of the process. By checking them monthly, you greatly increase the chances that the vast majority will be ready for spring.
Special Case: Winterizing Cannas in Pots
If you grow your canna lilies in large containers, the process is even simpler. You don't necessarily have to dig the rhizomes out of the soil. For a smaller patio-friendly choice, Canna Short Pink Magic is a strong option.
Once the frost has killed the foliage, cut the stalks down to the soil level as you would with garden-planted cannas. Move the entire pot into a frost-free area like a garage or basement. Stop watering the pot completely. The soil will dry out, and the rhizomes will go dormant right where they are.
In the spring, you can pull the clump out of the pot, refresh the soil, divide the roots if they have become pot-bound, and start watering again. This is a great "shortcut" for those with limited time or garden space.
Transitioning to Spring
As the days get longer and the threat of frost passes, you will start to see signs of life. You might even notice little white or pink "pips" poking through the packing material in your storage boxes. This is an exciting sign that your cannas are ready to go back to work.
Wait until the soil temperature in your garden reaches about 60°F before planting them outside. Cannas love heat, and they won't do much in cold, wet spring soil. If you want a bold foliage accent next season, Canna Tall Tropicanna Gold is a vivid choice. If you want to get an early start, you can pot them up indoors about 4 to 6 weeks before the last frost date. This gives them a "jump start" so they are already several inches tall when it is finally time to move them into the garden.
By saving your own rhizomes, you’ll find that each year your canna display gets bigger and more impressive. The small effort of winterizing pays off with a spectacular, tropical summer landscape that costs you nothing but a little bit of time.
Conclusion
Winterizing canna lily bulbs is a rewarding part of the gardening cycle. By following the natural cues of the seasons and providing a safe place for your plants to rest, you ensure that your garden remains a vibrant, tropical oasis year after year. The process of digging, curing, and storing is a simple way to connect more deeply with the rhythm of your landscape.
- Wait for the first frost to signal dormancy before you begin digging.
- Ensure the rhizomes are cured for several days to prevent rot in storage.
- Store your packed containers in a cool, dark place between 40°F and 50°F.
- Check your stored roots once a month to maintain the perfect moisture balance.
At Longfield Gardens, we believe that gardening should be a source of joy and accomplishment. Taking the time to care for your cannas over the winter is a small task that yields huge results. For more about our promise, see our 100% Quality Guarantee. When those first green shoots emerge next spring, you’ll be glad you took these simple steps to preserve your beautiful summer blooms.
"The secret to a stunning summer garden often lies in the quiet work we do during the autumn months. Protecting your cannas is a simple investment in next year's beauty."
FAQ
How do I know if my canna rhizomes have rotted during storage?
A healthy rhizome should feel firm and heavy for its size. If a rhizome feels "squishy," light, or hollow, it has likely rotted or dried out completely. You may also see visible mold or notice a sour smell. Always discard these pieces immediately to keep the rest of your collection healthy.
Can I store my canna lilies in the refrigerator?
While a refrigerator provides a cool, dark environment, it is often too cold and too dry for long-term storage. Most refrigerators are kept around 35°F to 38°F, which is a bit too close to freezing. If you have no other choice, wrap them in several layers of newspaper and place them in the crisper drawer, but check them frequently for moisture loss.
Is it necessary to wash the soil off the rhizomes before storing?
It isn't strictly necessary to wash them perfectly clean, and many gardeners simply shake off the excess dirt. However, washing allows you to inspect the rhizomes more clearly for pests or damage. If you do wash them, remember that the curing (drying) phase is even more important to ensure no moisture is trapped in the storage box.
When is the best time to divide my cannas?
You can divide cannas either in the fall after digging or in the spring before planting. Many people prefer spring because the "eyes" or growth points are more visible then, making it easier to see exactly where to make the cuts. If you divide in the fall, just make sure the cut ends have plenty of time to dry and callus before being packed away.