Table of Contents
- Introduction
- Understanding Your Climate and Canna Hardiness
- When to Leave Canna Lilies in the Ground
- How to Dig and Lift Canna Rhizomes
- Dividing Canna Rhizomes for More Flowers
- Best Practices for Winter Storage
- Growing Cannas in Containers to Simplify Winter
- When to Replant in the Spring
- Essential Summer Care for Best Blooms
- Troubleshooting Common Canna Questions
- Why Canna Lilies are Worth the Effort
- Conclusion
- FAQ
Introduction
Bringing a touch of the tropics to your backyard is one of the most rewarding parts of the summer gardening season. Canna lilies, with their massive, banana-like leaves and brilliant, jewel-toned flowers, transform any standard flower bed into an exotic escape. At Longfield Gardens, we love how these fast-growing plants provide architectural height and vibrant color from midsummer right up until the first frost.
Whether you are growing the deep bronze foliage of Tropicanna or the sunny yellow blooms of 'Yellow King Humbert,' you may be wondering what happens to these heat-loving plants once the temperatures begin to drop. The answer to whether you need to dig them up depends almost entirely on where you live and your specific garden goals. This guide will help you understand the simple steps for overwintering your cannas so you can enjoy their spectacular show year after year.
While cannas are remarkably resilient, they are tropical plants at heart and have specific needs when it comes to cold weather. By following a few straightforward rules for your climate zone, you can ensure your plants stay healthy and ready to sprout again when spring returns. For a broader overview, see All About Cannas.
Understanding Your Climate and Canna Hardiness
The first step in deciding if you need to dig up your canna lilies—which grow from thick, underground stems called rhizomes—is identifying your USDA plant hardiness zone. If you're unsure, check our Hardiness Zone Map. These zones are a standard used by gardeners to determine which plants can survive the winter in a specific location.
Canna lilies are generally considered hardy in zones 8 through 11. In these warmer regions, the ground does not freeze deep enough to damage the rhizomes. If you live in these areas, you typically do not have to dig up your cannas. They can stay in the ground year-round, entering a brief period of dormancy before sprouting again in the spring.
For gardeners in zones 3 through 7, the winter temperatures are usually cold enough to freeze the soil several inches deep. Because canna rhizomes are full of moisture, they cannot survive being frozen solid. In these colder climates, lifting the rhizomes and storing them indoors is the best way to preserve your favorite varieties for the following season.
It is helpful to think of your hardiness zone as a starting point. Your local microclimate, such as a sheltered spot near a brick foundation or a particularly wind-exposed hill, can also influence how well your plants handle the cold. If you are in zone 7, you are in a "swing" zone where a thick layer of mulch might be enough to keep the plants safe in the ground, but many gardeners choose to dig them up just to be certain.
When to Leave Canna Lilies in the Ground
If you are lucky enough to garden in a frost-free or mild-winter climate (Zones 8-11), your canna lilies can remain in their permanent garden home. This makes them a very low-maintenance addition to your landscape. However, "leaving them in the ground" does not mean leaving them completely alone. A little bit of autumn cleanup will help the plants look their best and stay healthy.
Wait for the foliage to begin yellowing or for the first light frost to singe the leaves. This is the plant's signal that it is time to rest. Use a pair of clean garden shears to cut the stems down to about 4 to 6 inches above the soil line. Removing the spent foliage prevents pests from nesting in the old leaves and gives your garden a tidy appearance for the winter.
In zone 8, and sometimes in zone 7, it is a great idea to apply a "winter blanket." Spread a 4- to 6-inch layer of organic mulch—such as shredded bark, pine needles, or straw—over the area where the cannas are planted. This mulch acts as insulation, keeping the soil temperature more consistent and protecting the rhizomes from unexpected cold snaps. In the spring, once the soil warms up, you can pull this mulch back to allow the new shoots to emerge.
What to do next: Warm Climate Care
- Wait for foliage to yellow or a light frost to occur.
- Cut stems back to 4-6 inches above the soil.
- Apply a thick layer of mulch in zones 7 and 8 for extra protection.
- Clear away the mulch in late spring when the ground warms.
How to Dig and Lift Canna Rhizomes
For those of us in colder regions, digging up canna lilies is a standard autumn ritual. While it might sound like a big task, it is actually quite simple and can be done in an afternoon. The best time to start is right after the first "black frost"—the first night when temperatures drop enough to turn the canna leaves dark brown or black. This frost tells the plant to move all its energy down into the rhizome for storage.
To begin, cut the stalks down to about 3 or 4 inches. This gives you a "handle" to work with and makes the clump easier to manage. Use a garden fork or a sturdy shovel to dig a wide circle around the base of the plant. Canna rhizomes can spread quite a bit during a single growing season, so start digging at least 12 inches away from the main stem to avoid accidentally slicing through the roots.
Gently pry the clump out of the soil. You will likely find that a single rhizome planted in the spring has grown into a large, heavy mass of several interconnected pieces. Shake off the excess soil with your hands. You do not need to wash the rhizomes with water; in fact, keeping them dry is better for the storage process.
Once the clumps are out of the ground, move them to a protected area like a garage or a porch for a few days. This "curing" period allows any remaining soil to dry and the outer skin of the rhizome to toughen up. Curing is a simple step that helps prevent rot during the long winter months.
Dividing Canna Rhizomes for More Flowers
One of the most exciting parts of digging up canna lilies is seeing how much they have multiplied. A single rhizome can often produce three to five new sections in one summer. Autumn or early spring is the perfect time to divide these clumps, which is essentially like getting free plants for your garden.
Look for the "eyes" on the rhizome. These are small, rounded bumps or points that look similar to the eyes on a potato. Each eye is a potential new stalk. Using a sharp, clean knife, you can cut the large mass into smaller sections. Ensure that each section has at least one or two healthy eyes and a good portion of the thick rhizome body.
If you prefer to wait, you can store the large clumps whole and divide them in the spring. Some gardeners find that storing the clumps whole helps keep the rhizomes from drying out too much. If you choose to divide them in the fall, allow the cut surfaces to dry and "callous" over for a day before putting them into storage. This creates a natural barrier against moisture and fungus.
Best Practices for Winter Storage
Successful overwintering is all about balance. You want the rhizomes to stay dormant and cool, but not so dry that they shrivel up, and not so wet that they rot. The ideal storage temperature is between 40°F and 50°F. An unheated basement, a crawl space, or a cool closet in a garage is usually the perfect spot.
Choose a storage container that allows for some air circulation. Cardboard boxes, plastic bins with holes drilled in the sides, or even paper grocery bags work well. To keep the rhizomes cushioned and to regulate moisture, pack them in a slightly damp medium. Common choices include:
- Peat moss: Excellent for holding just enough moisture.
- Vermiculite or Perlite: Lightweight and clean.
- Shredded newspaper: A great, budget-friendly option.
- Wood shavings: Often sold as animal bedding, these work beautifully.
Place a layer of your chosen material in the bottom of the box, then add a layer of rhizomes so they aren't touching each other. Cover them with more material and repeat until the box is full.
It is a good habit to check on your stored cannas once a month. If the rhizomes feel shriveled or dry, lightly mist the packing material with water. If you notice any soft spots or signs of mold, remove the affected piece immediately so it doesn't spread to the healthy ones. This simple "look-in" once a month ensures you'll have healthy plants ready to go in the spring.
Key Takeaway: Successful Storage The goal of winter storage is to keep the rhizomes in a "sleeping" state. By providing a cool, dark, and slightly humid environment, you mimic the conditions of a dormant tropical winter, keeping the plant's energy reserves intact for a strong spring start.
Growing Cannas in Containers to Simplify Winter
If the idea of digging in the dirt every autumn doesn't appeal to you, there is a very easy shortcut: grow your canna lilies in large pots. See How to Grow Summer Bulbs in Containers for more details. Cannas thrive in containers, provided they have plenty of water and fertilizer. In fact, Short Cannas are tailor-made for patio life.
When you grow cannas in pots, overwintering becomes a matter of moving the container rather than digging up the plant. Once the first frost hits and you have trimmed back the foliage, simply move the entire pot—soil and all—into a cool, frost-free area like a basement or garage.
The soil in the pot acts as a natural insulator and keeps the rhizomes from drying out. You don't need to water the pots during the winter; the goal is to let the soil stay dry so the plant remains dormant. In the spring, you can bring the pots back outside, give them a good soak and some fresh fertilizer, and watch the new shoots emerge. This "pot-in, pot-out" method is a fantastic time-saver for busy gardeners.
When to Replant in the Spring
Patience is a virtue when it comes to replanting canna lilies. Because they are tropical, they love warm soil. Planting them too early in cold, wet earth can cause the rhizomes to sit dormant for too long or even rot.
The golden rule for cannas is to wait until the soil temperature reaches at least 60°F. A good indicator for many gardeners is the timing of tomato planting; when it is safe to put your tomatoes in the ground, it is usually safe for your cannas. This is typically several weeks after the last frost date for your area.
Before planting, take a look at your garden spot. Cannas are "heavy feeders," meaning they need plenty of nutrients to produce those giant leaves and flowers. Mixing a few inches of compost or well-rotted manure into the soil will give them the fuel they need.
Plant the rhizomes about 4 inches deep and space them 1 to 2 feet apart, depending on the variety. Larger types need more room to breathe and spread. Make sure the "eyes" are pointing up toward the sky. If you can't tell which way is up, don't worry—the plant will figure it out and the shoot will find its way to the surface.
Essential Summer Care for Best Blooms
Once your cannas are back in the ground and growing, a few simple care steps will ensure they reach their full potential. For more seasonal care tips, see How to Care for Canna Lily Bulbs.
Cannas are not plants that enjoy a "hands-off" approach to watering. In their native habitats, they often grow near water or in boggy areas. In your garden, they will be happiest if the soil is kept consistently moist.
During the hottest parts of the summer, you may find yourself watering your cannas every other day, especially if they are in containers. A layer of mulch around the base of the plants helps hold that moisture in and keeps the roots cool.
To keep the flowers coming all summer long, practice "deadheading." This simply means cutting off the flower stalks once the blooms have faded. Canna stems often produce several clusters of flowers. When one cluster finishes, snip it off to encourage the plant to put energy into the next one. Once the entire stalk has finished blooming, you can cut that stalk back to the foliage level.
Finally, remember that cannas are sunshine lovers. They need at least 6 to 8 hours of direct sunlight to produce the most vivid leaf colors and the best flowers. If they are planted in too much shade, they may become tall and "leggy," and they won't bloom as reliably.
Troubleshooting Common Canna Questions
Gardening is a learning process, and even the most experienced growers have questions now and then. If your cannas aren't performing quite like you expected, the solution is usually found in one of the basics: sun, water, or temperature.
If your canna has plenty of leaves but no flowers, it is often a sign that it needs more light or more food. Check if nearby trees have grown and are now casting too much shade. You can also try a balanced, slow-release fertilizer to give the plant an extra boost.
If you see holes in the leaves or "rolled" leaf edges, you might have a visitor like the canna leaf roller. These are small caterpillars that hide inside the leaves. While they rarely kill the plant, they can make the foliage look a bit messy. You can often manage them by simply hand-picking the affected leaves or using a gentle, garden-safe spray as recommended by your local extension office.
One common concern for new canna growers is how slow they are to start in the spring. Do not be discouraged if you don't see green shoots for a few weeks after planting. Cannas are like many of us—they don't like to get out of bed until it is truly warm outside. Once the nights stay consistently above 50°F and the days are hot, they will grow with incredible speed.
What to do next: Summer Success
- Ensure plants get 6-8 hours of full sun.
- Keep the soil consistently moist, especially during heatwaves.
- Fertilize every 4-6 weeks with a balanced garden food.
- Deadhead faded blooms to encourage a continuous show.
Why Canna Lilies are Worth the Effort
While the process of digging and storing cannas takes a small amount of effort, the reward is a garden that looks like a high-end botanical display. Very few plants can match the sheer leaf surface area and the tropical "wow factor" that cannas provide. They are excellent for creating privacy screens, adding drama to the back of a flower border, or acting as a centerpiece in a large container.
At Longfield Gardens, we believe that gardening should be a joy, not a chore. The rhythm of planting in the spring and lifting in the fall connects us to the seasons and the life cycle of our plants. There is a special satisfaction in seeing a rhizome you carefully tucked away in a box all winter suddenly burst into life and reach six feet tall by August. We stand behind our 100% Quality Guarantee.
By understanding your zone and the simple needs of these tropical beauties, you can make canna lilies a permanent part of your gardening tradition. Whether you leave them in the ground or store them in the basement, they are a reliable, stunning, and endlessly versatile choice for any home landscape.
Conclusion
Determining whether you have to dig up your canna lily bulbs is a simple matter of checking your local winter temperatures. If you live in a warm climate, a bit of mulch is all they need. If you live in a cold climate, lifting them for the winter is a straightforward way to keep your garden favorites safe. These plants are incredibly forgiving and will reward a small amount of winter care with a massive display of summer beauty.
- Check your zone: Zones 8-11 can stay in the ground; Zones 3-7 should be lifted.
- Time it right: Dig after the first frost but before the ground freezes solid.
- Store correctly: Keep rhizomes cool, dark, and slightly damp in a breathable container.
- Replant in warmth: Wait for 60°F soil temperatures for the best spring start.
We are here to help you grow a more beautiful world, one bulb at a time. With a little bit of planning and the right care, your canna lilies will be the stars of your summer garden for years to come.
If you garden in a colder zone, Storing Canna Lily Bulbs Over Winter explains how to save your rhizomes for next year.
The most beautiful gardens are often the result of a little early planning. Starting your cannas indoors today is the first step toward a lush, tropical paradise this summer.
Ready to start your own tropical oasis? Visit our website to explore our full selection of canna lilies and find the perfect varieties for your garden this coming spring.
FAQ
What happens if I don't dig up my cannas in a cold zone?
If you live in a region where the ground freezes (Zone 6 and below) and you leave your cannas in the ground without protection, the moisture inside the rhizomes will freeze. This causes the cell walls to burst, and the rhizome will turn into a soft, mushy mess that cannot grow in the spring. In these areas, digging them up is the only way to ensure they survive the winter.
Can I store canna rhizomes in the garage?
You can store them in the garage as long as the temperature stays above freezing (usually 40°F to 50°F). If your garage is uninsulated and drops below 32°F, the rhizomes will likely be damaged. A cool corner of a basement or a crawl space is often a more consistent environment for winter storage.
Do I need to wash the dirt off the rhizomes before storing them?
It is actually better not to wash them. Using water can introduce too much moisture, which leads to rot during storage. Instead, let the clumps dry for a few days so the soil becomes loose and crumbly, then gently brush off the excess with your hands or a soft brush before packing them away.
How do I know if my stored rhizomes are still good in the spring?
Healthy rhizomes should feel firm and heavy, similar to a fresh ginger root from the grocery store. If they feel extremely light and hollow, they have likely dried out too much. If they feel soft, slimy, or have a foul smell, they have succumbed to rot. As long as they are firm and you see small "eyes" or buds, they are ready to be planted.