Table of Contents
- Introduction
- Identifying the Right Time to Dig
- Step-by-Step Harvesting Technique
- Cleaning and Trimming for Storage
- The Importance of Curing Rhizomes
- Choosing Your Storage Medium and Container
- Finding the Perfect Winter Storage Spot
- Monitoring Health Throughout the Winter
- Moving Potted Cannas Indoors
- Dividing and Replanting in the Spring
- What to Do Next
- FAQ
Introduction
There is nothing quite like the tropical flair of canna lilies to make a summer garden feel like a lush getaway. Their oversized, paddle-shaped leaves and brilliant orange, red, and yellow blooms bring a bold energy to the landscape that lasts from midsummer right up until the first frost. Watching hummingbirds zip from flower to flower among these tall beauties is one of the most rewarding parts of the growing season.
Because cannas are tropical plants, they thrive in the heat but are sensitive to freezing temperatures. In many parts of the country, the chilly winter months would naturally be the end of their story. However, with just a little bit of preparation, you can keep these spectacular plants for years to come. At Longfield Gardens, we enjoy helping gardeners maintain their favorite varieties by sharing the most effective ways to protect them during the off-season. If you are planning ahead, browse our Spring-Planted Summer-Blooming Bulbs.
This guide is designed for home gardeners who want to save their canna rhizomes (often called bulbs) rather than buying new ones every year. We will walk through how to harvest, clean, cure, and store them so they are ready to burst back into life when spring returns. Wintering canna bulbs is a straightforward process that rewards your effort with even bigger and more beautiful displays each summer. If you want a ready-made mix, start with our Canna Assorted Mix.
Identifying the Right Time to Dig
The most common question gardeners ask is exactly when to start the wintering process. Timing is the most important factor in ensuring the rhizomes have enough energy stored up for next year. Cannas spend the entire summer photosynthesizing and storing nutrients in their fleshy underground rhizomes. The longer you can leave them in the ground, the more robust those "bulbs" will be.
For most of the United States, the signal to begin wintering canna bulbs is the first light frost of autumn. You will know it has happened when the lush green or bronze foliage suddenly turns black or dark brown and begins to wilt. This frost effectively tells the plant that it is time to go dormant. While the top growth is killed by this cold snap, the soil usually remains warm enough to protect the rhizomes for a short while longer. If you are unsure when frost usually arrives in your area, the Hardiness Zone Map can help.
It is best to wait for this frost before digging. If you dig them up while the leaves are still green and healthy, you might cut the storage cycle short. However, you should not wait until the ground freezes solid. A deep freeze that reaches several inches into the soil can damage or kill the rhizomes. Aim to harvest your cannas within a week or two after that first frost blackens the leaves.
Key Takeaway: Wait for the first frost to turn the leaves brown or black. This signal tells the plant to move its energy into the rhizomes for winter storage.
Step-by-Step Harvesting Technique
Once the foliage has been hit by frost, it is time to get your tools ready. You will need a sturdy garden fork or a flat-bladed spade. A garden fork is often the preferred choice because it is less likely to accidentally slice through the fleshy rhizomes than a sharp shovel. If you prefer a taller look next summer, browse Tall Cannas.
Start by cutting the blackened stalks down to about 2 or 3 inches above the soil line. This makes the plants much easier to handle and gives you a "handle" to grab when lifting the clump. Next, clear away any mulch or debris from the base of the plant so you can see exactly where the stems meet the soil.
Cannas grow and expand horizontally under the ground, so the clump is likely much wider than it was when you planted it in the spring. To avoid damage, start digging about 6 to 10 inches away from the main stems. Push your fork or spade deep into the soil and gently pry upward. Work your way all the way around the plant, loosening the soil as you go.
Once the soil is loose, lift the entire clump out of the ground. Don't be surprised if the clump is heavy; a single canna can produce a massive root system in one season. Gently shake the clump to remove large chunks of soil. If the soil is heavy clay, you may need to use your hands to carefully pull away the largest clods.
- Cut stems to 3 inches above the ground.
- Dig at least 8 inches away from the center to avoid cutting rhizomes.
- Pry upward gently from all sides.
- Lift the entire mass and shake off loose dirt.
Cleaning and Trimming for Storage
After the rhizomes are out of the ground, they need a little bit of cleaning. Some gardeners prefer to leave a little bit of soil on the rhizomes, while others like them completely clean. The goal is to remove any hiding spots for pests and to get a good look at the health of the plant. For more seasonal care tips, see our How to Care for Canna Bulbs: A Complete Seasonal Guide.
You can use a garden hose with a gentle spray to wash away the remaining dirt. Avoid using high-pressure settings, as you don't want to nick or bruise the "skin" of the rhizome. These small injuries can become entry points for rot during the long winter months. If the soil is very dry and sandy, you might find that simply brushing it off with your hands is enough.
After cleaning, take a moment to inspect your harvest. Healthy canna rhizomes should feel firm to the touch, similar to a potato. If you find any soft, mushy, or foul-smelling spots, use a clean knife to trim those areas away. If a particular rhizome is mostly soft or shows signs of heavy insect damage, it is better to discard it now than to let it rot in storage and potentially infect the rest of your collection.
The Importance of Curing Rhizomes
One of the most overlooked steps in wintering canna bulbs is curing. Curing is simply the process of letting the rhizomes air-dry for a short period before they go into long-term storage. This step allows the outer skin to toughen up and any cuts or nicks to "callus" over. A well-cured rhizome is much more resistant to mold and rot. For a full walkthrough, read Storing Canna Lily Bulbs Over Winter: A Simple Guide.
To cure your cannas, find a spot that is dry, out of direct sunlight, and has good air circulation. A garage, a shed, or even a covered porch works well, provided the temperatures stay above freezing. Spread the rhizomes out in a single layer on a piece of cardboard, a wooden pallet, or a screen.
The curing process usually takes anywhere from two days to a full week, depending on the humidity in your area. You are looking for the exterior to feel dry and the cut ends of the stems to look shriveled and sealed. Once they reach this state, they are ready to be packed away for their winter nap.
Choosing Your Storage Medium and Container
The environment inside your storage container needs to strike a delicate balance. If it is too dry, the rhizomes will shrivel up and die. If it is too wet, they will rot. We recommend using a packing medium that can hold a tiny bit of moisture while still allowing the rhizomes to breathe.
Popular choices for storage media include:
- Peat Moss: This is a classic choice because it is sterile and holds moisture well.
- Vermiculite or Perlite: These provide excellent aeration and are very clean to work with.
- Wood Shavings: Often sold as pet bedding, these are inexpensive and effective.
- Shredded Newspaper: A great "no-cost" option that provides good insulation.
For containers, avoid anything airtight. Plastic bins with tight-fitting lids can trap moisture and cause the rhizomes to rot within weeks. Instead, use cardboard boxes, paper grocery bags, or plastic milk crates. If you do use a plastic bin, leave the lid off or drill several large holes in the sides to ensure plenty of airflow.
When packing, place a layer of your chosen medium at the bottom of the container. Place the rhizomes on top, making sure they aren't crowded or touching each other. Covering them with another layer of the medium helps insulate them and prevents them from drying out too quickly. If you have different colors or varieties, this is the perfect time to label them using a permanent marker directly on the rhizome or by attaching a tag to the box.
Key Takeaway: Use a breathable container like a cardboard box and a medium like peat moss or wood shavings to keep rhizomes firm but dry.
Finding the Perfect Winter Storage Spot
The location where you keep your boxes is just as important as how you pack them. Cannas need a spot that is cool and dark. Ideally, the temperature should stay between 40°F and 50°F throughout the winter.
If the storage area is too warm, the rhizomes might think it is spring and start to sprout prematurely. If it is too cold and drops below freezing, the water inside the fleshy roots will freeze, cell walls will burst, and the plant will turn into mush when it thaws.
Common successful storage locations include:
- Unheated Basements: Usually the most consistent environment for many gardeners.
- Crawl Spaces: These often stay at the perfect cool temperature.
- Attached Garages: Be careful here; ensure the boxes are placed against an interior wall to prevent them from getting too cold during a deep freeze.
- Root Cellars: The traditional and often most effective method.
Avoid spots near furnaces, water heaters, or large windows, as these areas fluctuate in temperature too much.
Monitoring Health Throughout the Winter
Wintering canna bulbs isn't entirely a "set it and forget it" task. It is a good habit to check on your storage boxes about once a month. This small effort can save your entire collection if something starts to go wrong.
When you open the boxes, feel a few of the rhizomes. They should still feel firm. If you notice any that are starting to feel soft or show fuzzy mold, remove them immediately so the problem doesn't spread to the healthy ones. If you see just a small spot of rot on a large, otherwise healthy rhizome, you can often cut the bad part away, let it dry for a day, and put it back.
If the rhizomes are starting to look shriveled or wrinkled, they are losing too much moisture. You can remedy this by lightly misting the storage medium with a spray bottle filled with water. You don't want the medium to be "wet," just slightly damp to the touch. This small boost in humidity is usually enough to keep them plump until spring.
Moving Potted Cannas Indoors
If you grow your cannas in large decorative pots, you have a shortcut available. You don't necessarily have to dig the rhizomes out of the soil. Instead, wait for the first frost to kill the foliage, cut the stems back to the soil line, and move the entire pot into a frost-free area like a basement or garage. For compact, container-friendly options, browse Short Cannas.
Stop watering the pots entirely once they are moved inside. The soil will dry out, and the plant will go into a deep dormancy. In the spring, about six weeks before the last frost date, you can move the pots back into a sunny spot and begin watering them again to wake them up. This method is much easier on the back, though it does require enough space to store large containers.
Dividing and Replanting in the Spring
One of the most exciting parts of growing cannas is how much they multiply. A single rhizome planted in May can easily turn into a clump of five or ten by October. While you can divide them in the fall, we find that at Longfield Gardens, it is often safer to wait until spring. For a refresher on planting depth, see How to Deep to Plant Canna Lily Bulbs for Best Results.
In the spring, usually about April or May depending on your location, take your rhizomes out of storage. You will see small "eyes" or bumps on the rhizomes, similar to the eyes on a potato. These are the points where new growth will emerge. Use a clean, sharp knife to cut the clumps into smaller sections. Each section should have at least two or three healthy eyes and a good amount of the fleshy "body" to provide energy.
Let the cut pieces sit for a day so the wounds can dry, and then they are ready to go back into the garden. Wait until the soil has warmed up and all danger of frost has passed before planting them outside. Most gardeners find that late spring, around the same time you would plant tomatoes, is the perfect window.
What to Do Next
Wintering canna bulbs is one of the most satisfying "circular" tasks in the garden. It connects one season to the next and allows you to build a massive collection of tropical color without a massive investment. By following these simple steps, you ensure that the vibrant flowers you loved this year will be back to greet you again next summer. If you like planning by palette, browse our Spring Planted Bulbs by Color.
- Check your calendar: Note the typical first frost date for your area so you aren't caught off guard.
- Gather your supplies: Get your cardboard boxes and peat moss or wood shavings ready before the cold weather hits.
- Label your plants: If you have multiple colors, mark them now while they are still in bloom so you know which is which come spring.
Wintering cannas is a simple, rewarding process that transforms a one-season plant into a lifelong garden companion. With a cool spot and a little bit of care, your garden will be ready for a tropical explosion every year.
We are here to help you make your garden the most beautiful it can be. For mid-height plantings, explore our Medium Cannas. For the best selection of high-quality cannas and other summer-blooming bulbs, you can always rely on the premium varieties we offer at Longfield Gardens. Happy gardening!
FAQ
Should I wash the soil off my canna rhizomes before storing them?
Yes, it is generally better to gently wash or brush off the soil. Removing the dirt allows you to inspect the rhizomes for any signs of rot or insect damage and prevents pests from hitchhiking into your storage area. Just be sure to let the rhizomes dry thoroughly (cure) after washing so that no moisture is trapped against the skin when you pack them away.
Can I store my canna bulbs in a garage over the winter?
An attached garage can be a great storage spot as long as it stays above freezing. If your garage frequently drops below 32°F, the rhizomes will likely freeze and die. To be safe, place your storage boxes on a shelf rather than the cold concrete floor, and keep them against a wall that shares heat with the house.
What should I do if my stored canna rhizomes look shriveled in mid-winter?
Shriveling is a sign that the storage environment is too dry and the rhizomes are losing their internal moisture. If this happens, use a spray bottle to lightly mist the packing medium (like peat moss or wood shavings) with water. You want the medium to be barely damp, not soggy, which will help the rhizomes rehydrate without causing them to rot.
When is the best time to divide my canna rhizomes?
While you can divide them in the fall after digging, it is usually better to wait until spring. In the spring, it is much easier to see the "eyes" or growth points that will become new stalks. Dividing in the spring also reduces the risk of rot during the winter, as there are fewer open "wounds" on the plant tissue during the long dormancy period. For spring timing, When Can I Plant My Canna Lily Bulbs? is a helpful next read.