Table of Contents
- Introduction
- The Signal to Start: When the First Frost Hits
- Knowing Your Garden Zone
- Preparing to Dig Your Cannas
- The Importance of Curing
- Creating the Perfect Storage Environment
- Monitoring Your Cannas Over Winter
- Storing Cannas Grown in Containers
- Transitioning to Spring
- Success Is in the Basics
- Conclusion
- FAQ
Introduction
Few plants bring the vibrant, tropical energy of cannas to a backyard. Their bold, oversized leaves and fiery blossoms create a lush sanctuary all summer long, and you can browse our Cannas Bulbs for Sale collection for more options. As the season winds down, you may wonder how to keep these beauties safe so they can return for another show next year.
At Longfield Gardens, we believe that gardening should be a rewarding experience that stays simple and enjoyable. Knowing when to transition your garden from summer growth to winter rest is a key part of that journey, and our Shipping Information page can help you plan ahead. This guide is designed for any gardener who wants to master the timing and technique of overwintering canna rhizomes.
We will focus on identifying the perfect moment to start digging and the best ways to keep your plants healthy through the cold months. By following a few straightforward steps, you can ensure your cannas stay strong and ready to sprout again in the spring.
Timing your winter preparation correctly is the secret to maintaining a beautiful, perennial-style garden even in colder climates.
The Signal to Start: When the First Frost Hits
The most important rule for canna care is watching the weather. Cannas are tropical plants that love the heat, so they do not naturally handle freezing temperatures well. However, they actually benefit from a tiny bit of cold before they go into storage.
In most regions, the ideal time to dig up your canna rhizomes—which are the thick, fleshy underground stems often called "bulbs"—is right after the first light frost. You will know this has happened when you see the lush green or bronze foliage turn black or dark brown. This color change is completely normal and serves as a natural signal that the plant is ready for its winter nap.
Why Wait for the Frost?
It might be tempting to dig your cannas early while the weather is still pleasant, but waiting for that first frost serves a practical purpose. Throughout the summer, the leaves act like solar panels, collecting energy from the sun and sending it down into the rhizomes.
This energy storage continues right up until the foliage dies back. By allowing the leaves to stay on the plant as long as possible, you give the rhizomes more fuel to survive the winter and produce bigger blooms next season. Once the frost hits and the leaves wither, the plant has officially finished its work for the year.
Avoiding the Deep Freeze
While a light surface frost is helpful, a deep freeze is a different story. A light frost only affects the leaves and the very top of the soil. A hard, deep freeze can penetrate several inches into the earth. If the ground freezes solid around the rhizomes, the water inside the plant tissues can expand and cause the cells to burst. This leads to rot and mushy bulbs that will not grow back.
If you see a forecast for a sustained period of temperatures well below freezing, it is time to get out your shovel. Aim to have your cannas lifted and safely tucked away before the soil itself begins to freeze hard.
Knowing Your Garden Zone
Not every gardener needs to dig up their cannas. Whether or not you need to take this step depends entirely on where you live. The United States is divided into USDA hardiness zones based on average winter temperatures. Understanding your zone helps you decide if your cannas can stay in the ground or if they need a cozy spot indoors. Our Hardiness Zone Map makes it easy to check.
Zones 8 and Warmer
If you live in Zone 8, 9, 10, or higher, you are in luck. In these warmer climates, the ground rarely freezes deep enough to harm canna rhizomes. You can typically leave them in the soil all year. To keep them tidy, simply cut the dead foliage back to the ground after the first frost and cover the area with a few inches of mulch to protect the soil from temperature swings.
Zone 7: The Middle Ground
Zone 7 is what we often call a "transition zone." In a mild winter, cannas can often survive in the ground here, especially if they are planted in a protected area near a house or a south-facing wall. To give them the best chance, apply a thick layer of mulch—about 6 to 8 inches of straw, leaves, or wood chips. However, if a particularly harsh winter is predicted, digging them up is the safest bet to ensure they return.
Zones 6 and Colder
For gardeners in Zone 6 and below (including much of the Midwest and Northeast), cannas will not survive the winter in the ground. In these regions, digging them up is a mandatory part of fall garden cleanup. Because the ground freezes deep in these areas, the rhizomes need a frost-free environment to stay dormant but alive.
Key Takeaway: The "when" of digging cannas is dictated by your local weather. Wait for the first light frost to blacken the leaves, but act before the ground freezes solid.
Preparing to Dig Your Cannas
Once the foliage has turned dark and the timing is right, you can begin the harvesting process. Having the right tools and a clear plan makes the job go quickly. You don’t need anything fancy; a standard garden spade or a sturdy garden fork will work perfectly.
Step 1: Cutting Back the Stems
Before you start digging, it is helpful to clear away the top growth. Use a pair of garden shears or a sharp knife to cut the stems down. Leave about 2 to 4 inches of the stalk remaining above the soil. These short "handles" make it much easier to see where the rhizomes are located and give you something to hold onto while you lift them.
Step 2: Loosening the Soil
Canna rhizomes can grow quite large and spread out horizontally over a single season. To avoid damaging them, start digging several inches away from the base of the plant.
Insert your spade or fork straight down into the soil and gently pry upward. Work your way in a circle around the clump. The goal is to loosen the entire mass so it can be lifted as one piece. Avoid "chopping" into the center of the plant, as wounds can invite rot during storage.
Step 3: Lifting and Initial Cleaning
Once the clump is loose, lift it out of the ground. Don't worry if the mass of rhizomes is large and heavy; they often multiply significantly over the summer. Use your hands to brush away the largest chunks of soil.
You can give them a gentle shake to remove loose dirt. Some gardeners prefer to rinse their rhizomes with a hose to see them more clearly, but if you do this, you must be very careful to let them dry completely before storage. Excessive moisture is the biggest enemy of a dormant bulb.
The Importance of Curing
Curing is a simple but vital step that many people skip. It essentially means letting the rhizomes air-dry for a short period before they are packed away. This process allows the "skin" of the rhizome to toughen up, which helps it resist moisture loss and disease while it sits in storage.
How to Cure Your Rhizomes
Find a dry, well-ventilated spot that is protected from rain and frost. A garage, a garden shed, or even a covered porch works well. Spread the rhizomes out in a single layer.
Let them sit for about 3 to 7 days. During this time, any remaining soil will dry up and become easier to brush off. The cut ends of the stalks will also callous over. This protective layer acts like a scab, keeping fungi and bacteria out during the long winter months.
To Divide or Not to Divide?
Fall is a great time to look at your canna clumps and decide if you want more plants for next year. Since cannas multiply, you will likely have more than you started with. You can break the large clumps into smaller sections now, or wait until the spring. If you want a ready-made mix instead, see our Canna Assorted Mix - Bulk Offer.
Creating the Perfect Storage Environment
Once your cannas are dry and cured, they need a winter home. The ideal storage spot is cool, dark, and dry, but not freezing. You are looking for a temperature range between 40°F and 50°F.
Choosing Your Packing Material
You don't want to store canna rhizomes in airtight plastic bags, as they need to breathe. Instead, use materials that can manage moisture levels. Some popular choices include:
- Peat Moss or Vermiculite: These are excellent because they are sterile and hold just a tiny bit of moisture to keep the rhizomes from shriveling without making them wet.
- Newspaper: Wrapping individual rhizomes in newspaper is a simple, low-cost way to keep them separated and protected.
- Dry Leaves or Pine Needles: If you have these in your yard, they make a great, free insulating material.
Picking a Container
A cardboard box, a plastic bin with the lid left slightly ajar, or a paper grocery bag all make fine containers. Place a layer of your chosen packing material at the bottom, then add a layer of rhizomes. Repeat this until the container is full, making sure the rhizomes aren't packed so tightly that air cannot circulate.
What to do next:
- Find a sturdy cardboard box or paper bag for storage.
- Source a bag of peat moss or save some old newspapers.
- Choose a storage location like a basement, crawl space, or unheated closet.
- Label your boxes with the variety or color so you know what is what in the spring!
Monitoring Your Cannas Over Winter
Storing cannas isn't a "set it and forget it" task. To ensure the highest success rate, it is a good idea to check on your rhizomes about once a month. This small effort can save your entire collection if an issue arises.
Watching for Rot
When you check your boxes, look for any rhizomes that feel soft, mushy, or smell bad. If you find one that is starting to rot, remove it immediately. This prevents the rot from spreading to the healthy plants nearby. If only a small tip of a rhizome is soft, you can sometimes cut that part off with a clean knife and let the healthy portion dry out again.
Preventing Shriveling
On the other hand, if the rhizomes feel very light and look shriveled like a raisin, they might be getting too dry. In this case, you can use a spray bottle to lightly mist the packing material with a little water. You don't want it to be wet—just a tiny bit of humidity is enough to keep them plump and healthy.
Storing Cannas Grown in Containers
If you grow your cannas in large pots or decorative containers, you have an even easier option with Short Cannas. You don't necessarily have to dig the rhizomes out of the soil.
After the first frost kills the foliage, cut the stems back to the soil level just as you would in the garden. Then, move the entire pot into a frost-free area like a basement or garage. The soil in the pot will act as a natural insulator. You can leave the rhizomes right in the dirt until the spring. Just make sure the soil is dry when you move it inside; you don't want to store a soggy pot of dirt, as this will lead to rot.
Transitioning to Spring
While it feels like a long way off, spring will eventually arrive, and your cannas will be ready to grow. About 4 to 6 weeks before the last expected frost in your area, you can bring your boxes out of storage.
If you didn't divide them in the fall, now is the perfect time. Inspect them one last time, discarding anything that didn't make it through the winter. You can even "wake them up" early by planting them in pots indoors in a sunny window. This gives them a head start so they are already growing by the time you move them out to the garden.
By the time the soil warms up to about 60°F, your cannas will be ready to return to their rightful place in the landscape.
Success Is in the Basics
Gardening success often comes down to getting a few simple things right. With cannas, it is all about the transition from the garden to the storage box. By waiting for the frost, curing the rhizomes properly, and keeping them in a cool, dry place, you are following the same reliable methods we use in our own trial gardens.
We want you to feel confident in your garden year after year. Cannas are incredibly resilient plants, and they are very forgiving. Even if you lose a few to the winter, the ones that survive will often multiply so much that you'll have plenty to share with friends and neighbors.
Conclusion
Digging up canna bulbs for the winter is a straightforward task that preserves your investment and keeps your garden's story going from one year to the next. By watching for the first frost and providing a cool, dry resting place, you ensure these tropical stars return even bigger and better than before.
- Wait for the first frost to turn foliage brown.
- Cut stems to 2–4 inches before lifting.
- Cure rhizomes in a dry spot for several days.
- Store in a cool, frost-free location in breathable materials.
At Longfield Gardens, we are here to help you grow a more beautiful world, one season at a time. For a bold foliage choice next season, browse Canna Tall Tropicanna Black.
Overwintering cannas is a rewarding way to connect with the natural cycle of your garden. A little bit of care in the fall leads to a spectacular tropical display every summer.
FAQ
What happens if I dig up my cannas before the first frost?
You can dig them up early if you need to, but the plants may have less stored energy. The first frost serves as a natural signal for the plant to go dormant. If you dig early, make sure the foliage has at least started to yellow, and give them a longer curing period to ensure the rhizomes are ready for storage. For a different look next season, browse our Tall Cannas.
Can I leave my cannas in the ground if I live in Zone 7?
In Zone 7, cannas can often survive the winter if they are heavily mulched and planted in a protected spot, such as against a south-facing wall. However, because winter temperatures can be unpredictable, many gardeners choose to dig up at least a few rhizomes as a "backup" in case of a record-breaking cold snap. If you want to compare mid-sized options, browse our Medium Cannas.
Do I need to wash the dirt off the rhizomes before storing them?
While you can rinse them, it isn't strictly necessary and can sometimes be counterproductive if they don't dry out completely. Brushing off the loose soil after they have cured for a few days is usually sufficient. If you do wash them, ensure they are bone-dry before you pack them into boxes for the winter. For more planting and care basics, see All About Cannas.
How do I know if a canna bulb has rotted during storage?
A healthy canna rhizome should feel firm to the touch, similar to a fresh potato. If a rhizome feels squishy, looks slimy, or has a pungent, unpleasant odor, it has likely rotted. These should be discarded immediately so the bacteria or fungi do not spread to the healthy rhizomes in your storage container. If you have order questions or want to read about our Our Guarantee, we’re here to help.