Introduction
There is nothing quite like the tropical flair that canna lilies bring to a summer garden. With their lush, paddle-shaped leaves and brilliant, jewel-toned flowers, they turn any backyard into a private oasis. As the season winds down and the first frost approaches, many gardeners look for ways to save these beautiful plants so they can enjoy them again next year. At Longfield Gardens, we want to help you preserve that tropical magic by making the overwintering process as simple and successful as possible.
This guide is designed for home gardeners who want to know exactly where and how to keep their canna rhizomes (often called bulbs) safe during the cold months. We will cover the best locations in your home for storage, the right temperature settings, and how to pack them for the best results. Finding a cool, dark, and dry spot is the key to ensuring your cannas wake up ready to grow when spring returns.
Understanding Canna Lily Dormancy
Before choosing a storage spot, it is helpful to understand what the plant is doing during the winter. Cannas are tropical perennials that grow from thick, fleshy underground stems called rhizomes. In warm climates—specifically USDA hardiness zones 8 through 10—these rhizomes can usually stay in the ground all year. However, in most of the United States, the freezing winter temperatures will damage or kill the fleshy tissue.
When the weather turns cold, the canna lily naturally enters a state of dormancy. This is like a deep sleep where the plant stops growing and saves its energy. Your goal during storage is to maintain this dormancy. If the storage spot is too warm, the plant might try to grow too early. If it is too cold, the rhizomes may freeze and rot. By finding the right "middle ground" location, you keep the plant in a healthy state of rest.
To Dig or Not to Dig: The USDA Zone Decision
One of the most frequent questions we receive is whether you actually need to dig up your cannas. The answer depends heavily on your location and your garden's specific conditions.
In USDA zones 8 and warmer, cannas can stay in the ground year-round. In USDA zone 7, the decision is more nuanced. While the ground can freeze deep enough to damage rhizomes, many gardeners in zone 7 find success overwintering cannas in the ground by applying a heavy layer of mulch (6 to 10 inches) of straw or shredded leaves.
Your local microclimate also plays a major role. If your cannas are planted in a sheltered bed next to a south-facing foundation or a stone wall that retains heat, they may survive a zone colder than their official rating. However, if your soil is heavy clay that stays wet during the winter, the risk of rot is much higher, even in milder zones. If you are in zone 6 or colder, or if you want to ensure the survival of a favorite variety, digging and storing them indoors is the safest path.
The Ideal Storage Environment
The "perfect" storage spot for canna bulbs shares three main characteristics. If you can provide these three things, your success rate will be very high.
Cool Temperatures
The most important factor is temperature. You want a spot that stays consistently between 40°F and 55°F. This range is cool enough to keep the plant dormant but warm enough to prevent the tissue from freezing. Most modern living rooms are too warm, and an uninsulated shed is often too cold.
Low Light Levels
Cannas need darkness to stay dormant. Light is a signal to the plant that it is time to start photosynthesizing and growing leaves. By keeping them in the dark, you ensure they stay in their "sleep" mode until you are ready to plant them in the spring.
Managed Humidity
Rhizomes are living things that contain a lot of water. If the storage area is bone-dry, the rhizomes can shrivel up and die. If the area is too wet or has no airflow, they will likely grow mold or rot. A spot with moderate humidity and a little bit of air circulation is the best choice.
Troubleshooting Your Storage Space
Even if your storage area isn't perfect, we can usually make it work with a few adjustments:
- If the area is too warm (above 60°F): The cannas may start to sprout in February or March. If this happens, you will need to move them to a cooler spot or pot them up early to grow under lights.
- If the area is too cold (near freezing): Wrap your storage boxes in old blankets or move them away from exterior walls to provide extra insulation.
- If the area is too damp: Increase airflow by using mesh bags or keeping the lids off your boxes. Avoid storing containers directly on a damp concrete floor; use a pallet or shelf instead.
Best Locations to Store Canna Bulbs
Most homes have at least one or two spots that work well for winter plant storage. Here are the most common and effective locations.
An Unheated Basement
An unheated or "unfinished" basement is often the gold standard for storing cannas. These areas usually stay naturally cool because they are underground, but they rarely reach freezing temperatures because they are attached to the house. If your basement is heated, look for the corner furthest away from the furnace or water heater.
An Attached Garage
An attached garage can be a great option, but you must be careful. Because it shares a wall with your house, it often stays warmer than the outside air. However, in very cold climates, a garage can still drop below freezing. If you use a garage, place your storage boxes on a shelf rather than directly on the concrete floor. You can also move the boxes to an interior wall for extra warmth.
A Crawl Space
If your home has a crawl space that is accessible and dry, it can provide very stable temperatures throughout the winter. These spaces stay cool and dark, which is exactly what cannas want. Just make sure the area is not prone to flooding or excessive moisture, as this will cause the rhizomes to rot quickly.
A Root Cellar or Fruit Cellar
If you are lucky enough to have an old-fashioned root cellar, this is the perfect home for your canna bulbs. These spaces were designed specifically to keep produce at a stable, cool temperature without freezing. They provide the natural humidity that keeps rhizomes from drying out too much.
A Cool Closet
In some homes, an interior closet located on an outside wall or in a hallway far from a heat vent can stay cool enough for storage. This is a good option for gardeners living in apartments or smaller homes who do not have a basement or garage.
Key Takeaway: The best storage spot is one that stays between 40°F and 55°F, remains dark, and is protected from freezing. Basements and attached garages are the most popular choices for most home gardeners.
Preparing Cannas for Their New Home
Where you store your bulbs matters, but how you prepare them for that spot is just as important. Follow these simple steps to get them ready for their winter nap.
Wait for the First Frost
Let nature tell the plant when it is time to sleep. Wait until a light frost has turned the foliage brown or black. This signal tells the rhizome to pull all the remaining energy from the leaves down into the root system. Once the leaves are damaged by frost, you can cut the stalks down to about 2 to 4 inches above the soil.
Dig with Care
Use a garden fork or a shovel to gently lift the clumps out of the ground. Start your digging about a foot away from the base of the plant to avoid slicing through the rhizomes. Cannas often grow much larger than they were when you planted them, so give them plenty of space.
Dividing Your Canna Clumps
Once the clumps are out of the ground, we recommend dividing the largest ones before storage. Large, heavy clumps are difficult to pack and can harbor more moisture, which leads to rot. Use a sharp, clean knife to separate the rhizomes. Each division should be a healthy, firm section with at least 3–5 eyes (the small, rounded bumps where new growth will emerge). Smaller sections with only one eye can be stored, but they will take much longer to produce a full-sized plant in the spring.
The Curing Process
Before you put your cannas into their final storage spot, they need to "cure." This just means letting them dry out slightly. Shake off the big chunks of soil and let the rhizomes sit in a dry, shaded area—like a garage or a porch—for about 3 to 7 days.
During curing, look for the "dusty" stage. The outer skin should feel dry and slightly tough, and there should be no visible wet spots or "bleeding" from any cuts made during division. Curing helps the "skin" of the rhizome toughen up, which acts as a shield against rot and disease during the winter.
Cleaning vs. Not Cleaning
Some gardeners prefer to wash their rhizomes with a hose, while others prefer to leave the dirt on. Both methods can work. If you wash them, ensure they are 100% dry before packing them away. If you leave the soil on, just brush off the loose bits. Leaving a little bit of soil can actually help protect the rhizomes from drying out too fast.
Choosing Your Storage Containers
Once your cannas are cured and you have picked a spot in your home, you need to decide what to put them in. The goal is to allow the plants to "breathe" while keeping them from drying out completely.
- Cardboard Boxes: These are excellent because they are breathable. You can layer the rhizomes inside and close the top to keep the light out.
- Paper Bags: Large grocery bags are great for smaller collections. They allow for airflow and are easy to label with the variety name or flower color.
- Plastic Totes (with caution): If you use plastic bins, do not put the lid on tight. Drill several holes in the sides to allow air to move. Without airflow, the moisture trapped inside will cause the bulbs to rot.
- Milk Crates: These provide maximum airflow. If you use crates, you will likely need to use a packing medium to keep the rhizomes from drying out too much.
Using a Packing Medium
While you can store cannas "naked" in a box, most gardeners have better success when they use a packing medium. This material acts as a buffer, absorbing excess moisture but also preventing the rhizomes from becoming shriveled.
Common packing materials include:
- Peat Moss: This is the most popular choice because it holds just the right amount of moisture.
- Vermiculite or Perlite: These are sterile and very effective at managing moisture levels.
- Wood Shavings: Often sold as animal bedding, these are inexpensive and provide great airflow.
- Shredded Newspaper: A great recycled option that is easy to find.
To pack your cannas, place a layer of your chosen medium in the bottom of the container. Lay the rhizomes on top so they are not touching each other. Cover them with more medium and repeat the process until the box is full. This prevents any rot from spreading from one rhizome to another.
Storing Cannas in Their Pots
If you grow your cannas in large containers, you have a "shortcut" available. You don't actually have to dig them up. We often recommend this for beginners because it is very simple.
When the frost hits, cut the foliage back to the soil line. Move the entire pot—soil and all—into your cool storage area. The soil in the pot acts as a natural packing medium, protecting the rhizomes perfectly. In the spring, you can pull the pot out, start watering, and the plants will emerge. Every few years, you will still need to dig them up to divide the roots so they don't become too crowded.
Monitoring Your Cannas During Winter
Storage is not a "set it and forget it" task. To ensure you have plenty of healthy plants in the spring, we suggest checking on your storage boxes about once a month.
A Canna Viability Checklist
When you check your rhizomes, use this quick checklist to determine if they are healthy or if they need attention:
- Healthy (Firm and Plump): The rhizome should feel heavy for its size and be as firm as a potato. The "eyes" should be visible and not mushy.
- Too Dry (Shriveled): If the skin looks wrinkled like a raisin and the rhizome feels light or hollow, it is losing too much moisture. Use a spray bottle to lightly mist the packing medium.
- Unhealthy (Soft and Mushy): This is a sign of rot. If the rhizome gives way when squeezed or has a foul odor, it is no longer viable.
- Moldy: If you see white fuzzy growth, the area is too damp. Remove the affected piece, let the remaining rhizomes air dry for a day, and reduce the moisture in your packing material.
Most experienced gardeners expect to lose a few rhizomes over the winter. If 80% of your plants survive until spring, you are doing a fantastic job.
What to do next:
- Check your storage area once a month for consistent temperature.
- Remove any soft or mushy rhizomes immediately to protect the rest of the batch.
- If rhizomes look shriveled, lightly mist the packing material with a spray bottle.
- Keep a thermometer in your storage space to ensure it stays between 40°F and 55°F.
Moving from Storage to Spring Planting
When the days start getting longer and the threat of a hard freeze has passed, it is time to wake up your cannas. This usually happens in late April or May for most of the country.
You can give your cannas a head start by bringing the storage boxes into a warm, bright room about four to six weeks before the last frost date. We suggest inspecting each rhizome one last time for firmness before planting. You can even start canna lily bulbs indoors in pots with fresh soil. Place them in a warm spot (around 70°F) near a sunny window or under grow lights to encourage early sprouting.
Before you move them into the garden, make sure the soil is warm. Cannas love heat and won't do much if the ground is still cold and soggy. Once the soil reaches a consistent 60°F, you can plant them with confidence. If you've pre-sprouted them, be sure to "harden them off" by gradually exposing them to outdoor conditions over a week before final planting.
Enjoying the Rewards
Saving your own canna lilies is one of the most rewarding parts of gardening. It allows you to grow your collection year after year without spending more money. Plus, because cannas multiply underground, you will often find that you have twice as many plants in the fall as you did in the spring.
At Longfield Gardens, we believe that gardening should be a joy, not a chore. While digging and storing bulbs might seem like a big task, it actually only takes an hour or two on a crisp autumn afternoon. The reward—a yard full of vibrant, tropical color all summer long—is well worth the small effort.
"Winter storage is simply a way to hit the pause button on your garden. By providing a cool, dark, and stable environment, you are giving your plants the rest they need to perform beautifully next season."
Conclusion
Finding the right place to store canna lily bulbs doesn't have to be complicated. Whether you choose a corner of your basement, a spot in the garage, or a cool crawl space, the goal remains the same: keep them cool, dark, and dry. By following these simple steps for digging, curing, and packing, you can preserve your favorite varieties for years to come.
As you prepare your garden for winter, remember these key steps:
- Wait for the first frost before digging.
- Divide large clumps, ensuring 3–5 eyes per piece.
- Cure the rhizomes for several days until the skin feels dry and dusty.
- Store them in a breathable container between 40°F and 55°F.
- Check them once a month to ensure they stay firm and healthy.
We invite you to explore our website for more tips on growing beautiful summer blooms. Your garden journey is a rewarding adventure, and we are honored to be a part of it. Happy gardening, and we look forward to seeing your cannas thrive next spring!
FAQ
Can I store canna lily bulbs in the refrigerator?
While a refrigerator is cool and dark, it is generally not recommended for canna storage. Refrigerators are often too cold (usually around 35°F), which can damage the tropical tissue over a long period. Additionally, many refrigerators have low humidity, which can cause the rhizomes to shrivel and die.
Should I cut the roots off the canna rhizomes before storing?
It is best to leave the small, fibrous roots alone when you dig up the clumps. These roots will naturally dry out during the curing process. Removing them by force can create small wounds on the main rhizome where rot or fungus can enter. You can easily trim away the dried bits in the spring before planting.
My storage area is very dry; how can I keep canna bulbs from shriveling?
If you are storing cannas in a very dry environment, like a modern basement with a furnace, use a packing medium like peat moss or wood shavings. These materials hold a small amount of residual moisture around the rhizome. Check them monthly and give the packing material a very light misting of water if it feels bone-dry.
Is it okay to store canna rhizomes in plastic bags?
You can use plastic bags, but you must be very careful with airflow. Solid plastic bags will trap moisture and almost certainly cause the rhizomes to rot. If you prefer using plastic, use a mesh bag (like an onion bag) or punch several dozen large holes in a plastic grocery bag to ensure the air can circulate freely.
