Table of Contents
- Introduction
- Understanding Canna Rhizomes
- When Is the Best Time to Dig?
- Preparing Your Cannas for Storage
- How to Dig Canna Rhizomes Safely
- Cleaning and Drying the Rhizomes
- Choosing Your Storage Medium
- Packing Your Cannas for the Winter
- The Ideal Storage Environment
- Monthly Maintenance: The Winter Check-In
- Dividing Cannas During Storage
- Special Considerations for Container Cannas
- Handling Warm Climate Exceptions
- Common Myths About Canna Storage
- Preparing for Spring Planting
- Conclusion
- FAQ
Introduction
There is something truly magical about the way canna lilies transform a backyard into a tropical paradise. Their oversized, paddle-shaped leaves and brilliant blossoms bring a lush, exotic energy to the garden that lasts all summer long. At Longfield Gardens, we believe that the joy of growing these vibrant cannas should continue year after year.
Because cannas are tropical plants, they thrive in the heat of summer but cannot survive freezing temperatures. In most parts of the United States, keeping these plants for next year requires a little bit of winter preparation. This process is often called "overwintering," and it is much simpler than many gardeners realize.
This guide will show you exactly how to dig, clean, and store your canna rhizomes so they stay healthy until spring. Whether you are a beginner or a seasoned gardener, you can easily save your favorite varieties to enjoy again. By following a few straightforward steps, you can ensure your cannas have a restful winter and a spectacular return.
Understanding Canna Rhizomes
Before we jump into the storage process, it is helpful to know what you are looking at under the soil. While many people refer to them as "bulbs," cannas actually grow from rhizomes. A rhizome is a thick, fleshy underground stem that stores energy and water for the plant. For more background, read All About Cannas.
Think of the rhizome as a battery. Throughout the summer, the leaves soak up sunlight and turn it into food. This food is sent down to the rhizome to be stored. By the end of the season, a healthy canna plant has a plump, sturdy rhizome filled with everything it needs to grow again next year.
The skin of a canna rhizome is relatively thin, which is why they need protection from both freezing and drying out. When we talk about storing them, our goal is to keep that "battery" charged and hydrated without letting it get so damp that it rots. It is a simple balance that ensures your garden stays beautiful every summer.
When Is the Best Time to Dig?
Timing is one of the most important parts of successful storage. You want to give your cannas as much time as possible to store energy, but you must get them out of the ground before a hard freeze damages the rhizomes.
The best signal to start the process is the first light frost of autumn. You will notice the tips of the leaves turning brown or black after a chilly night. This frost tells the plant that the growing season is over and it is time to go to sleep. This natural cue triggers the plant to move its final bits of energy down into the rhizome.
If you live in a region where frost comes very late, you can simply wait until the foliage starts to yellow naturally in late autumn. However, if a "hard freeze" (where the ground begins to crust with ice) is in the forecast, you should dig them up immediately. A light frost on the leaves is fine, but frozen soil can damage the rhizomes themselves. If you're unsure, check the hardiness zone map first.
Preparing Your Cannas for Storage
Once the first frost has touched the leaves, the foliage will begin to look a bit bedraggled. This is your green light to begin. You do not need to wait for the entire plant to turn brown; once the leaves are damaged by cold, they are no longer feeding the plant.
Start by cutting the stalks back. Use a clean pair of garden shears or a sharp knife to cut the stems about 2 to 4 inches above the soil line. Leaving a small "handle" of the stem makes it easier to move the clumps without accidentally breaking off the growing points, which are often called "eyes."
After cutting back the foliage, clear away any mulch or garden debris from around the base of the plant. This gives you a clear view of where the rhizomes are located so you can avoid hitting them with your tools.
Key Takeaway: Wait for the first light frost to signal dormancy, then cut the stalks down to a few inches above the soil before you start digging.
How to Dig Canna Rhizomes Safely
Digging cannas is a rewarding task because you will often find that the single rhizome you planted in spring has multiplied into a large, heavy clump. To lift them safely, you will need a garden spade or a sturdy garden fork.
Step-by-Step Lifting
- Give Them Space: Start digging about 6 to 10 inches away from the base of the stems. If you dig too close, you might slice through a healthy rhizome.
- Loosen the Soil: Circle the entire clump with your shovel, pushing it straight down into the dirt. This severs the long, thin feeder roots that grow out from the rhizomes.
- Lift Like a Lever: Once you have circled the plant, slide your shovel underneath the clump and gently pry upward. Work your way around the plant until the entire mass of soil and rhizomes lifts easily out of the ground.
- Shake Off the Excess: Gently lift the clump and shake it to remove the largest chunks of soil. Do not bang the rhizomes against a hard surface, as bruises can lead to rot during the winter.
If you have cannas growing in large pots, the process is even easier. You can simply tip the pot over on a tarp and gently pull the soil away from the rhizomes.
Cleaning and Drying the Rhizomes
After the rhizomes are out of the ground, they need a little bit of grooming before they go into storage. This step helps prevent soil-borne diseases from following the plants into your basement or garage.
To Wash or Not to Wash?
There are two ways to handle the soil. Some gardeners prefer to let the soil dry for a few hours and then gently brush it off with their hands. Others prefer to use a garden hose to wash the rhizomes clean.
Washing them with a hose allows you to see the health of the rhizome clearly. You can spot any soft spots or insect damage easily. However, if you wash them, you must be very careful to let them dry completely before packing them away. Excessive moisture is the primary cause of rot in storage.
The Curing Process
Curing is just a fancy word for letting the outer skin of the rhizome dry and toughen up. Place your cleaned rhizomes in a single layer in a well-ventilated area. A garage, a covered porch, or a garden shed works perfectly. Keep them out of direct sunlight and away from freezing temperatures.
Let them sit for 2 to 7 days. During this time, the cut ends of the stems will dry out and the outer skin of the rhizomes will become less susceptible to mold. Once they feel dry to the touch and the leftover soil is crumbly, they are ready for their winter home.
Choosing Your Storage Medium
You cannot simply toss canna rhizomes into a plastic bin and hope for the best. They need a storage medium that regulates moisture. The goal is to keep the air around the rhizome slightly humid so it doesn't shrivel, but dry enough that it doesn't mold.
Here are the most successful options:
- Peat Moss: This is a classic choice. It is naturally sterile and does a great job of holding just a tiny bit of moisture.
- Wood Shavings: The kind used for pet bedding (like cedar or pine) is excellent. It allows for great air circulation and is very affordable.
- Vermiculite: This mineral-based material is very clean and keeps the rhizomes well-insulated.
- Newspaper: If you only have a few rhizomes, you can wrap each one individually in several layers of dry newspaper.
- Potting Soil: Some gardeners use dry potting soil. Just make sure it is fresh and hasn't been used for other plants, which could introduce pests.
Avoid using heavy garden soil or sand. Garden soil can hold too much moisture and harbor bacteria, while sand is often too heavy and doesn't provide enough insulation.
Packing Your Cannas for the Winter
Now that your rhizomes are clean and cured, and you have chosen your medium, it is time to pack them away. You can use cardboard boxes, plastic storage bins, or even breathable burlap bags.
If Using a Plastic Bin
If you choose a plastic bin, do not put the lid on tightly. Rhizomes are living things and they need to breathe. If you seal them up, moisture will condense on the inside of the lid and drip back onto the plants, causing them to rot. Instead, leave the lid slightly ajar or drill several small holes in the sides of the bin for ventilation.
The Layering Method
Place a 2-inch layer of your chosen storage medium at the bottom of the container. Lay the rhizomes on top so they are not touching each other. Covering each one with the medium prevents any potential rot from spreading from one plant to another. Add another layer of medium, then more rhizomes, until the container is full.
Labelling
This is the step many gardeners forget! Canna rhizomes all look very similar once the leaves are gone. Use a permanent marker to write the variety name or the color directly on the rhizome or on a wooden garden tag tucked into the box. If you are saving several different varieties, Assorted Cannas can be a helpful place to compare options for next season.
What to do next:
- Label each rhizome variety clearly.
- Choose a breathable container like a cardboard box.
- Layer the rhizomes so they do not touch.
- Cover them completely with peat moss or wood shavings.
The Ideal Storage Environment
Where you keep your stored cannas is just as important as how you pack them. They need a location that stays consistently cool but never reaches the freezing point.
The ideal temperature range is between 40°F and 55°F.
- Unheated Basements: Usually the most reliable spot in many homes.
- Crawl Spaces: Good, as long as they stay dry.
- Cool Closets: An interior closet that stays away from heater vents can work.
- Attached Garages: Be careful here. If your garage regularly drops below freezing in the winter, it is not a safe spot for cannas.
Keep the containers in a dark place. Light can sometimes trick the rhizomes into thinking it is spring, which might cause them to start growing prematurely. This uses up their stored energy before they even hit the soil.
Monthly Maintenance: The Winter Check-In
Overwintering is not a "set it and forget it" task. To ensure a 100% success rate, you should check on your cannas about once a month throughout the winter.
Open your boxes and take a quick peek at a few rhizomes. You are looking for two things:
- Signs of Rot: If you see any soft, mushy spots or white fuzzy mold, remove that rhizome immediately. If only a small part is affected, you can sometimes cut away the soft part and let the rest dry out. If it is mostly rotten, discard it so it doesn't infect the others.
- Signs of Shriveling: If the rhizomes look very wrinkled or feel lightweight and hollow, they are too dry. Use a spray bottle to lightly mist the storage medium with water. You don't want it to be wet—just slightly damp like a wrung-out sponge.
This simple monthly check takes only five minutes but can save your entire collection from a mid-winter disaster.
Dividing Cannas During Storage
As we mentioned earlier, cannas are great at multiplying. A single rhizome can turn into a massive clump in just one season. You can divide these clumps to create more plants for your garden or to share with friends. If you want a mid-size option, browse Medium Cannas.
The best time to divide cannas is either right after you dig them up in the fall or just before you plant them in the spring. Many gardeners find it easier to do in the spring when the "eyes" (the small bumps where new growth starts) are more visible.
To divide them, use a clean, sharp knife. Each piece should have at least one or two healthy eyes and a good section of the fleshy rhizome attached. Letting the cut ends dry for a day before planting (or storing) helps prevent disease.
Special Considerations for Container Cannas
If you grow your cannas in pots, you have a shortcut available. You don't necessarily have to dig the rhizomes out of the dirt. For more tips on pot size and planting, see How to Grow Summer Bulbs in Containers.
After the first frost, cut the foliage back to the soil level. Move the entire pot into a cool, frost-free area like a basement. Stop watering the pot completely. The soil will dry out, and the cannas will go dormant right inside the container. A compact choice like Short Cannas is especially easy to manage in containers.
In the spring, you can bring the pot back out, give it a fresh layer of compost, and start watering again. However, keep in mind that cannas grow very fast. After one or two years, the rhizomes will become "root-bound," meaning they have filled the entire pot. At that point, you will need to tip the pot over, divide the rhizomes, and repat them with fresh soil. If you like bold foliage, Canna Short Orange Chocolate is another good container option.
Handling Warm Climate Exceptions
If you live in USDA hardiness zones 8, 9, or 10, you may not need to dig your cannas at all. In these warmer regions, the ground rarely freezes deep enough to harm the rhizomes. If you want to compare larger varieties, browse Tall Cannas.
In Zone 8, many gardeners simply cut the stalks to the ground and apply a thick 4-to-6-inch layer of mulch (like straw, bark, or shredded leaves) over the top of the plants. This acts as a warm blanket for the winter.
If you live in Zone 7, you are in a "swing" zone. In a mild winter, cannas will survive with heavy mulch. In a very cold winter, they might not. If you have a variety you absolutely love and cannot bear to lose, it is always safer to dig and store a few rhizomes just in case.
Common Myths About Canna Storage
There is a lot of advice on the internet about storing cannas, and not all of it is helpful. Let's clear up a few common misconceptions.
Myth: You must use fungicide powder. While some people like to dust their rhizomes with sulfur or fungicide, it is usually not necessary if your rhizomes are healthy and your storage medium is clean. Good airflow and correct moisture levels are much more important.
Myth: Cannas need to stay "warm" in the winter. Actually, they need to stay cool. If they are kept too warm (above 60°F), they won't enter a true state of dormancy. They might try to grow in the dark, resulting in weak, white sprouts that waste the plant's energy.
Myth: You should store them in the dark under the kitchen sink. While it is dark, the area under a sink is often too warm and humid due to household plumbing. A basement or a cool corner of a utility room is a much better choice.
Preparing for Spring Planting
When the days begin to lengthen and the threat of frost passes, it is time to wake up your cannas. Most gardeners start this process about 4 to 6 weeks before the last expected frost date.
Take the rhizomes out of their storage containers and inspect them one last time. They should feel firm. If you haven't divided them yet, now is the perfect time. How to Plant Canna Lily Bulbs is a helpful refresher before you get started.
You can give your cannas a head start by planting them in pots indoors before moving them to the garden. Place them in a sunny window and keep the soil lightly moist. By the time the weather is warm enough to plant them outside, you will already have several inches of lush green growth.
Cannas love warm soil. Wait until the ground is at least 60°F before planting them outdoors. If you plant them too early in cold, wet soil, they will simply sit there and may even struggle. Patience pays off with cannas—once the heat of June hits, they will grow at an incredible pace.
Conclusion
Storing canna bulbs over the winter is one of the easiest ways to save money and preserve the beauty of your garden. By listening to the signals of the seasons and providing a cool, dry place for your rhizomes to rest, you ensure a spectacular display for the following year. At Longfield Gardens, we want every gardener to feel confident in caring for their plants through every season. Our 100% Quality Guarantee helps make that possible.
The process of digging and storing cannas is a satisfying way to wrap up the gardening year. It gives you a chance to see how much your plants have grown and to prepare for an even more beautiful landscape next summer.
Winter Storage Checklist:
- Dig after the first light frost.
- Clean and cure the rhizomes for a few days.
- Pack in a breathable medium like wood shavings or peat moss.
- Store in a cool (40-55°F), dark, frost-free location.
- Check for moisture or rot once a month.
With these simple steps, your cannas will be ready to bring their tropical flair back to your garden as soon as the summer sun returns. Happy gardening!
FAQ
Can I store canna rhizomes in plastic bags?
You can use plastic bags, but they must have several air holes punched in the sides to allow for ventilation. If the bag is sealed tight, moisture will build up and cause the rhizomes to rot very quickly. Most gardeners find that paper bags or cardboard boxes are much safer and more breathable options. For more winter-storage tips, see Winter Storage for Tender Bulbs and Tubers.
What should I do if my stored rhizomes look wrinkled?
If your rhizomes look shriveled or wrinkled, they are becoming dehydrated. Simply use a spray bottle to lightly mist the storage medium (the peat moss or wood shavings) with water. Do not soak the rhizomes directly; just add enough moisture to the surrounding material so the air isn't quite so dry.
Should I wash the soil off the rhizomes before storing them?
You can either wash them or gently brush the dry soil off. Washing with a hose is helpful because it allows you to see any damage or rot clearly, but it requires you to let the rhizomes dry thoroughly for several days before packing. If you live in a very humid climate, brushing off dry soil may be safer to avoid trapped moisture.
How do I know if a canna rhizome is dead?
A healthy rhizome should feel firm, similar to a fresh ginger root or a potato. If the rhizome feels hollow, very light, or squishy like a sponge, it is likely dead or rotten. If it is brown and mushy inside when you cut into it, it should be discarded to prevent the spread of disease to your healthy plants. If you want more planting inspiration, browse Fresh Ideas for Growing Cannas.