Introduction
There is nothing quite like the bold, tropical energy that canna lilies bring to a summer garden. With their massive, paddle-shaped leaves and vibrant flowers in shades of red, orange, and yellow, they turn any backyard into a lush retreat. At Longfield Gardens, we love how these plants provide vertical interest and a splash of color that lasts from midsummer right up until the first frost. Whether you are growing a tall variety like 'Tropicanna' or a more compact dwarf type, the question eventually arises as the weather cools: do you have to dig up canna lily bulbs to keep them alive for next year?
The answer depends mostly on where you live and your local winter temperatures. While often called "bulbs," cannas actually grow from thick, fleshy underground stems known as rhizomes. These rhizomes are tropical by nature, meaning they are sensitive to freezing temperatures. In this guide, we will help you determine if your cannas can stay in the ground or if they need a cozy spot indoors for the winter. We will also walk you through the simple steps for lifting, storing, and replanting them so you can enjoy these spectacular plants year after year.
Understanding your gardening zone and the needs of your rhizomes is the best way to ensure a successful bloom next season. For a detailed overview of canna biology and care, see our All About Cannas guide.
Understanding Canna Lily Hardiness
To decide if you need to dig up your canna lilies, you first need to know your USDA Plant Hardiness Zone. This system divides North America into zones based on their average annual minimum winter temperature. Cannas are tropical perennials, and their survival through the winter is entirely dictated by how deep the frost reaches into the soil. Our Canna Lily Growing Zone Guide provides additional information about matching canna care to your climate.
In general, canna lilies are considered hardy in zones 8 through 11. In these warmer climates, the ground rarely freezes deep enough to reach the rhizomes. If you live in these areas, you can typically leave your cannas in the ground all year round. They will go dormant during the cooler months and begin growing again once the soil warms up in the spring.
If you live in zone 7, you are in a "borderline" area. Depending on the severity of the winter and how well-protected your garden is, cannas might survive outdoors if they are heavily mulched. However, for gardeners in zones 6 and colder, the ground freezes solid enough to kill the rhizomes. In these regions, digging them up is a necessary step if you want to save your plants for the following summer.
Key Takeaway
- Zones 8–11: Usually safe to stay in the ground.
- Zone 7: May stay in the ground with heavy mulching, but lifting is safer.
- Zones 3–6: Must be dug up and stored indoors to survive the winter.
Why Temperature Matters for Canna Rhizomes
It helps to think of a canna rhizome as a storage tank for energy. During the summer, the large leaves soak up sunlight and turn it into food, which is then stored in the thick rhizome underground. Because these plants evolved in tropical regions of Central and South America, they never developed a way to survive cellular freezing.
When the soil temperature drops below freezing and stays there, the water inside the rhizome cells expands as it turns to ice. This causes the cell walls to burst, effectively turning the firm, healthy rhizome into a soft, mushy mess that will eventually rot. For a closer look at why cannas are rhizomes rather than true bulbs, read Are Canna Lilies Bulbs or Tubers?
By digging them up in colder climates, you are simply moving that "energy tank" into a frost-free environment where it can rest until the sun returns.
When to Dig Up Your Canna Lilies
Timing is everything when it comes to overwintering cannas. 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 itself freezes solid.
The best signal to start the process is the first "blackening frost." This is a light frost that kills the foliage, turning the bright green or burgundy leaves to a dark brown or black. This frost tells the plant it is time to go dormant. Once the leaves have been hit by frost, you can safely cut the stalks back to about 4 to 6 inches above the ground.
Do not worry if you cannot get to them the very next day. The rhizomes are protected by the soil for a short time. However, you should aim to have them lifted and moved into storage within a week or two of the first frost. If you live in an area where the ground freezes quickly after the first frost, keep a close eye on the weather forecast so you aren't trying to dig in frozen earth.
Steps to Take Before Digging
- Monitor your local weather for the first fall frost.
- Wait for the foliage to turn brown or black after a frost.
- Cut the stems back to about 4–6 inches.
- Clear away any support stakes or labels so you have a clear workspace.
How to Dig Up Canna Lily Rhizomes
Lifting cannas is a straightforward process, but it requires a bit of care to avoid damaging the fleshy rhizomes. Since cannas can grow quite vigorously over a single season, the clumps are often much larger than the single rhizome you originally planted.
Start by using a garden fork or a sturdy shovel. Dig a circle around the base of the plant, staying about 12 inches away from the stems. This ensures you aren't slicing through the new growth that happened underground during the summer. Gently pry the soil upward from several sides to loosen the entire clump.
Once the clump is loose, lift it out of the hole. You will likely see a large mass of roots and soil clinging to the rhizomes. Gently shake off the excess dirt. You don't need to wash them with a hose—in fact, keeping them dry is better for storage—but you want to remove the bulk of the garden soil so you can see what you are working with.
Pro Tip: While you have the clumps out of the ground, take a moment to inspect them. Healthy rhizomes should feel firm, like a fresh potato. If you see any soft or mushy spots, trim those away with a clean knife before moving to the next step.
Cleaning and Curing for Storage
After digging, the rhizomes need a short period of "curing." This is a simple process of letting the outer skin dry and toughen up, which helps prevent rot and mold during the long winter months.
Place your lifted clumps in a dry, shaded area for a few days. A garage, garden shed, or a covered porch works perfectly. Avoid leaving them in direct, hot sunlight, as this can dry them out too much. During this time, the remaining soil will dry up and fall away easily. You can also trim the remaining stems down to about an inch or two above the rhizome at this stage.
If the clumps are very large, you can choose to divide them now or wait until spring. Dividing involves breaking the large mass into smaller sections. Each section must have at least one "eye"—a small, rounded bump where next year's growth will emerge. Many gardeners prefer to keep the clumps whole during winter and divide them in the spring when the eyes are more visible and active.
Best Practices for Winter Storage
The goal of storage is to keep the rhizomes dormant, cool, and just slightly hydrated. If the storage area is too warm, they may try to grow prematurely. If it is too damp, they will rot. If it is too dry, they may shrivel up and lose their vitality.
We recommend storing canna rhizomes in a breathable container. Cardboard boxes, plastic bins with air holes, or even paper bags work well. To maintain the right moisture balance, layer the rhizomes in a packing medium. Common choices include:
- Peat moss
- Vermiculite
- Coarse sawdust
- Shredded newspaper
Place a layer of your chosen medium in the bottom of the container, add a layer of rhizomes (making sure they aren't touching each other), and cover them with more medium. Repeat until the box is full.
The ideal temperature for storage is between 40°F and 50°F. A cool basement, an unheated crawl space, or a frost-free garage is usually the best spot. Check on your rhizomes once a month during the winter. If they look shriveled, give the packing medium a very light misting of water. If you spot any mold or soft spots, remove the affected rhizome immediately to prevent the problem from spreading to the rest of the batch.
Overwintering Cannas in Warm Climates (Zones 8–11)
If you are lucky enough to live in a region where the ground does not freeze, your work is much simpler. You do not have to dig up your canna lily bulbs at all. However, a little bit of "winterizing" will keep the garden looking tidy and ensure the plants come back strong in the spring.
Once the foliage begins to yellow or die back in late fall, cut the stems down to the ground. In zone 7 and the cooler parts of zone 8, it is a good idea to apply a 4-to-6-inch layer of mulch over the planting site. Straw, pine needles, or shredded leaves work well to insulate the soil and protect the rhizomes from any unexpected cold snaps.
In these warmer zones, cannas can sometimes become overcrowded over several years. If you notice that your plants are producing fewer flowers or the foliage seems cramped, you may want to dig and divide them every 3 to 4 years during their dormant period, even if you plan to put them right back into the ground.
Replanting Cannas in the Spring
When the days grow longer and the threat of frost has passed, it is time to bring your cannas back into the garden. In most regions, this is around the same time you would plant your tomatoes—usually late May or early June. The soil needs to be warm, at least 60°F, for cannas to start growing.
Take the rhizomes out of storage and inspect them one last time. They should still be firm. If you kept them as large clumps, now is the perfect time to divide them. Simply pull them apart or use a sharp, clean knife to cut them into sections, ensuring each piece has at least one healthy eye.
Cannas love sun and rich soil. Choose a spot that gets at least 6 to 8 hours of direct sunlight. Before planting, we recommend mixing some compost or well-rotted manure into the soil to give them the nutrients they need for their rapid summer growth. Dig a hole about 4 inches deep, lay the rhizome in horizontally with the eyes facing up, and cover it with soil. Water them well to settle the earth and jump-start the hydration process.
What to do next:
- Check your last frost date.
- Inspect stored rhizomes for firmness.
- Divide large clumps into smaller sections with at least one eye.
- Wait for soil temperatures to reach 60°F before planting.
- Plant 4 inches deep in a sunny, nutrient-rich spot.
Growing Cannas in Containers
For many gardeners in northern climates, growing cannas in large pots is the easiest way to manage the "digging" question. Because pots can be moved, you can get a head start on the season by starting them indoors or in a greenhouse and then moving them to the patio once it is warm. For additional advice, see this guide to growing cannas in containers.
When the season ends, you don't necessarily have to remove the rhizomes from the pots. Instead, you can simply cut the foliage back after the first frost and move the entire container into a cool, frost-free area like a basement or garage. Stop watering completely so the soil dries out and the plant stays dormant. In the spring, you can move the pot back outside, start watering again, and watch them wake up.
Keep in mind that cannas grow fast. Even in a large pot, the rhizomes will eventually fill the entire space. Every year or two, it is best to tip the pot over, remove the mass, and divide the rhizomes to prevent them from becoming root-bound.
Troubleshooting Common Winter Issues
While overwintering cannas is generally a high-success activity, a few common issues can pop up. Most of these are easily fixed by adjusting your storage conditions.
If you find that your rhizomes are consistently rotting in storage, it is usually a sign of too much moisture or poor air circulation. Make sure you are using a breathable container and that the packing medium is only barely damp, not wet. On the other hand, if the rhizomes are as light as a feather and brittle, they have dried out too much. A slightly more closed container or a bit more packing material can help hold in the necessary humidity.
Another common concern is early sprouting. If you see white or pale green shoots appearing in February or March, your storage area is likely too warm. Move the container to a cooler spot to slow them down. If they continue to grow, you can pot them up and grow them as indoor plants near a sunny window until it is safe to move them outside.
The Reward of Saving Your Cannas
Saving your canna rhizomes is one of the most rewarding tasks in the garden. Not only does it save you the cost of buying new plants every year, but it also allows you to grow a collection of your favorite varieties that get larger and more impressive each season.
There is a great sense of satisfaction in pulling a firm, healthy rhizome out of storage in May and knowing it holds the potential for a six-foot-tall tropical masterpiece. At Longfield Gardens, we believe that gardening should be an achievable and enjoyable journey. Taking these simple steps to protect your plants through the winter is a small investment of time that pays off in a spectacular summer show.
Our rhizomes are sourced from trusted growers to ensure they arrive at your door in prime condition, ready to grow. We stand behind our quality with a 100% guarantee, so you can plant with confidence knowing your garden will be beautiful.
FAQ
Can canna lilies survive a freeze?
The foliage of a canna lily will be killed by a freeze, but the underground rhizomes can survive as long as the ground itself does not freeze. In zones 8 and warmer, the soil temperature typically stays high enough to protect the plant. In zones 7 and colder, a hard freeze that penetrates the soil will kill the rhizomes, which is why digging them up is recommended.
How do I know if my canna rhizomes are still good?
A healthy canna rhizome should be firm to the touch, similar to a fresh ginger root or a potato. If you squeeze it and it feels hollow, brittle, or mushy, it is likely no longer viable. You can often see small "eyes" or growth points on healthy rhizomes, which may be pink or white when they are ready to sprout.
Do I have to wash the dirt off before storing them?
It is actually better not to wash canna rhizomes before storing them. Introducing extra moisture right before they go into storage can increase the risk of rot or fungal issues. Instead, let the clumps dry for a day or two in a shaded area and then gently brush off the loose soil by hand.
Can I leave cannas in pots over the winter?
Yes, you can leave cannas in their containers if you live in a cold climate. After the first frost, cut the foliage back and move the entire pot into a frost-free area like a basement or garage. Do not water the pot during the winter; the goal is to keep the soil dry and the rhizome dormant until spring arrives. For more container-specific advice, read How Many Canna Bulbs Per Container.
Conclusion
Determining whether you have to dig up your canna lily bulbs is a simple matter of knowing your climate. If you live in a warm region, a little mulch and a seasonal trim are all you need. If you live in the north, lifting and storing your rhizomes is a straightforward process that ensures your tropical favorites return year after year. By following the steps of digging after the first frost, curing the rhizomes, and storing them in a cool, dry place, you can grow a spectacular garden with ease.
- Know your USDA zone to decide if digging is necessary.
- Wait for the first frost to signal dormancy.
- Store rhizomes in a cool, dry, frost-free environment.
- Check on your stored plants monthly to ensure they remain firm.
At Longfield Gardens, we are here to help you succeed with premium plants and practical advice. We ship high-quality rhizomes directly to your door, timed perfectly for your local planting season. For details about timing shipments by growing zone, see our Shipping Information. If you are ready to add a tropical touch to your landscape, start exploring the vibrant colors and varieties we have to offer today!
"Protecting your cannas through the winter is a simple way to ensure your garden remains a lush, tropical paradise year after year with very little effort."
