Table of Contents
- Introduction
- Understanding the Canna Rhizome
- The Signal: When to Start Digging
- Step-by-Step Digging and Cleaning
- The Curing Process
- Selecting Your Storage Materials
- Finding the Right Winter Home
- Maintaining Your Rhizomes in Storage
- Dividing Cannas for More Plants
- Storing Container-Grown Cannas
- Planning for Spring Emergence
- Conclusion
- FAQ
Introduction
The lush, architectural foliage and vibrant blooms of cannas are the highlights of many summer gardens. These tropical favorites transform backyards into exotic retreats, offering months of color and height. One of the most rewarding parts of growing them is knowing that these spectacular plants can return year after year, often growing larger and more impressive with each passing season. For the current selection, browse our Cannas Bulbs for Sale.
At Longfield Gardens, we enjoy helping gardeners preserve their favorite varieties through the winter months. While cannas are tender perennials that cannot survive freezing ground temperatures in many regions, the process of saving them is straightforward and highly effective. With just a little bit of preparation in the autumn, you can protect your plants and prepare for an even bigger display next summer. If you want to compare heights, start with Tall Cannas.
This guide is designed to help you navigate the simple steps of digging, cleaning, and storing your canna rhizomes. Whether you are a beginner or an experienced gardener, you will find that overwintering is a practical way to expand your garden collection. Saving your canna rhizomes is a simple, rewarding process that ensures your favorite varieties return even more vigorously next season. If you want a ready-made mix, browse Assorted Cannas.
Understanding the Canna Rhizome
Before we dive into the storage process, it is helpful to understand exactly what you are working with. Although most gardeners refer to them as "bulbs," cannas actually grow from rhizomes. A rhizome is a thick, fleshy horizontal stem that grows underground. It acts as a storage organ, holding the energy and nutrients the plant needs to sprout and grow when warm weather returns. For a fuller overview, see All About Cannas.
When you look at a canna rhizome, you will notice small bumps or points known as "eyes." These eyes are the growth points where new stalks will emerge in the spring. During the summer growing season, a single rhizome will often multiply into a large clump. This natural expansion is one of the many reasons why storing them is so beneficial; you often end up with more plants than you started with.
Understanding that these are living, breathing structures is the key to successful storage. They need to stay dormant—essentially a deep winter sleep—without drying out completely or becoming too wet. The goal of winter storage is to provide a stable environment that mimics their natural rest period while protecting them from the fatal chill of frost.
The Signal: When to Start Digging
Timing is everything when it comes to overwintering cannas. You want to give the plants as much time as possible to store energy in their rhizomes, but you must get them out of the ground before the soil freezes solid.
The most common signal for digging is the first light frost of autumn. When temperatures dip just below freezing, the lush green or bronze leaves of your cannas will turn black or brown. This might look disappointing at first, but it is actually a helpful cue from nature. This "frosting" tells the plant to stop sending energy to the leaves and to focus entirely on the underground rhizome. For more timing details, see When Do I Dig Up Canna Lily Bulbs?.
If you live in an area where frost comes very late, or if you simply want to get a head start, you can dig them up once the foliage begins to yellow or look tired in late autumn. However, waiting for that first touch of frost is usually the best way to ensure the rhizome is fully "charged" for its winter nap.
Key Takeaway: Wait for the first light frost to blacken the foliage before digging. This ensures the rhizome has stored the maximum amount of energy for next year's growth.
Step-by-Step Digging and Cleaning
Once the foliage has been hit by frost, it is time to lift the rhizomes. You will need a few basic tools: a garden fork or a sturdy spade, a pair of garden shears, and perhaps a garden hose.
Cutting Back the Foliage
Start by cutting the stalks down. Use your shears to trim the blackened stems to about 3 or 4 inches above the soil line. These short "handles" of stem make the rhizomes easier to manage and help you keep track of which way is up during the initial cleaning process. Removing the bulk of the foliage also makes it much easier to see where the base of the plant meets the soil.
Lifting the Clumps
Cannas can develop surprisingly large root systems over a single summer. To avoid damaging the fleshy rhizomes, start digging about 6 to 12 inches away from the base of the stems. Instead of digging straight down, use a garden fork to gently pry the soil upward from several sides of the clump.
Once the soil is loosened, you can lift the entire mass out of the ground. It is often easier to lift the whole clump at once rather than trying to separate pieces while they are still buried. If the clump is particularly large and heavy, don't be afraid to ask for a second set of hands or to break it into two manageable halves with your spade.
Initial Cleaning
After the clump is out of the ground, gently shake it to remove large chunks of loose soil. You can use your hands to brush away excess dirt, being careful not to bruise the skin of the rhizomes. While some gardeners prefer to wash their rhizomes with a hose to see the "eyes" more clearly, others prefer to leave a little bit of soil on them to help prevent them from drying out too quickly. If you want a quick checklist for judging storage stock, read How to Tell if Canna Bulbs are Good.
If you do choose to rinse them, make sure they are allowed to dry thoroughly before the next step. Excess water trapped in the nooks and crannies of the rhizomes can lead to rot during storage.
The Curing Process
Curing is a brief but vital step that prepares the rhizomes for several months of dormancy. After digging and cleaning, the rhizomes need a short period to "air out" and allow their outer skins to toughen up slightly.
Place your cleaned rhizomes in a protected, well-ventilated area that stays out of direct sunlight and away from frost. A garage, a covered porch, or a garden shed works perfectly. Lay them out in a single layer on a piece of cardboard or a newspaper.
The curing process usually takes between one and three days. You aren't looking to dry them out until they are shriveled; you simply want the surface moisture to evaporate and any small nicks or cuts from the digging process to "callous" over. This callous acts as a natural seal against fungi and bacteria that could cause decay during the winter.
What to Look for During Curing
- Firmness: The rhizomes should feel heavy and firm, like a fresh ginger root or a potato.
- Healthy Color: They should be creamy white or tan.
- Damage Check: If you notice any sections that were badly crushed or are showing signs of soft rot, trim those parts away with a clean, sharp knife before the curing process is finished.
Selecting Your Storage Materials
Once your cannas are cured, they need to be packed away. Because rhizomes are fleshy, they can lose moisture and shrivel if left completely exposed to the air. On the other hand, if they are sealed in an airtight plastic bag, they can rot from their own respiration. The goal is to find a middle ground.
Peat Moss and Vermiculite
One of the most popular methods is to use slightly damp peat moss or vermiculite. These materials are excellent at regulating moisture. We find that placing a layer of peat moss in a cardboard box or a plastic bin with air holes, then nestled the rhizomes inside, provides a very stable environment.
Wood Shavings or Sawdust
Pine shavings, often sold as animal bedding at pet or farm supply stores, are another excellent option. They allow for great airflow while still providing enough insulation to keep the rhizomes from drying out. They are also very easy to handle and relatively inexpensive.
Newspaper and Cardboard
For a very simple approach, you can wrap each rhizome individually in a few sheets of dry newspaper. The paper acts as a buffer, preventing any rot from spreading from one rhizome to another while still allowing the plant to breathe. Place the wrapped rhizomes inside a cardboard box or a breathable crate.
What to Do Next: Packing Checklist
- Select a breathable container (cardboard box, crate, or plastic bin with holes).
- Add a 2-inch layer of your chosen medium (peat, shavings, or shredded paper).
- Place rhizomes in the container so they aren't quite touching each other.
- Cover completely with more storage medium.
- Label the container with the variety name and the date.
Finding the Right Winter Home
The location where you keep your storage containers is just as important as how you pack them. Cannas need a spot that is "cool but not cold."
The ideal temperature range for storing canna rhizomes is between 45°F and 55°F (7°C to 13°C). If the temperature stays in this range, the rhizomes will remain dormant and healthy. If it gets too warm (above 60°F), they might try to start growing prematurely. If it gets too cold (below 40°F), they may suffer chill damage or freeze, which will kill the plant.
Common Storage Locations
- Unheated Basements: Usually the most consistent environment in many homes.
- Crawl Spaces: These often stay at a perfect, steady temperature, but make sure they are dry.
- Attached Garages: These can work well, but you must be careful that the temperature doesn't drop below freezing during a cold snap. Keep the boxes off the concrete floor and away from exterior walls.
- Root Cellars: These are traditionally designed for this exact purpose and provide excellent humidity and temperature control.
Key Takeaway: Find a dark, cool spot that stays consistently between 45°F and 55°F. Avoid any area where the temperature could drop below freezing.
Maintaining Your Rhizomes in Storage
Storing your cannas isn't a "set it and forget it" task. To ensure the highest success rate, you should check on your rhizomes about once a month throughout the winter. This simple habit allows you to catch any potential issues early.
Checking for Moisture
If you open your box and the rhizomes feel very light or the storage medium feels bone-dry and dusty, they may be losing too much moisture. If they look slightly shriveled, use a spray bottle to lightly mist the storage medium. You don't want it to be wet—just a tiny bit of humidity is enough to plump them back up.
Monitoring for Rot
If you find a rhizome that feels soft, mushy, or has a sour smell, it is beginning to rot. Remove it immediately so the decay doesn't spread to its neighbors. If only a small part of a large rhizome is soft, you can sometimes save the rest by cutting away the bad part with a clean knife and letting the cut end dry out for a day before putting it back in the box.
Checking for Pests
Occasionally, small critters like mice or certain insects might find your storage boxes. If you see signs of nibbling, consider moving the containers to a more secure location or placing them inside a fine wire mesh.
Dividing Cannas for More Plants
One of the most exciting aspects of cannas is how much they multiply. A single rhizome planted in May can easily become a clump of five or more by October. You can divide these clumps either in the fall before you pack them away or in the spring before you plant them. For a dramatic container variety, shop Canna Tall Tropicanna.
We often recommend waiting until spring to do your final division. This is because it is easier to see the "eyes" once the plant is ready to wake up. However, if your clumps are simply too large to fit into your storage boxes, you can divide them in the fall.
To divide, use a clean, sharp knife or even your hands to snap the rhizomes apart. Ensure that every piece you keep has at least one or two prominent "eyes." Each of these pieces will grow into a full, beautiful plant the following summer. If you divide in the fall, remember to let the cut surfaces cure for an extra day before packing them into their winter medium.
Storing Container-Grown Cannas
If you grow your cannas in pots or large decorative containers, the process is even easier. You don't necessarily have to dig the rhizomes out of the soil.
Once the frost has hit the foliage, cut the stalks down to the soil line as usual. Move the entire pot—soil and all—into your cool, dark storage area. The soil in the pot acts as a natural insulator and storage medium. For another striped foliage option, shop Canna Tall Australia.
Throughout the winter, keep the soil dry. You may only need to give it a very tiny splash of water once or twice over the entire winter to prevent the soil from becoming completely desiccated. In the spring, you can tip the pot over, refresh the soil, divide the rhizomes if they have become crowded, and bring them back out into the sun.
Planning for Spring Emergence
As winter winds down and the days begin to lengthen, it is time to start thinking about bringing your cannas out of storage. This usually happens about 4 to 6 weeks before the last expected frost date in your area. For a step-by-step indoor-starting companion, see How to Start Planting Canna Bulbs Indoors.
Waking Them Up
Take the rhizomes out of their boxes and inspect them one last time. They should be firm and may even be showing tiny white or pink nubs at the eyes. If you want to get an even earlier start on the season, you can "pre-start" your cannas indoors.
Plant the rhizomes in pots with some fresh potting soil and place them in a warm, sunny window. Giving them this head start indoors means you will have larger plants and earlier flowers once the outdoor weather is warm enough for transplanting. If you want another bold option, shop Canna Tall Pretoria.
Moving Outdoors
Cannas love warmth. Wait until the soil has warmed up and all danger of frost has passed before planting them in the garden. They thrive in full sun and rich, well-draining soil. Because they are heavy feeders, a bit of compost or a balanced fertilizer at planting time will help them reach their full tropical potential.
Conclusion
Learning how to store canna bulbs for the winter is a simple way to enjoy these tropical beauties for years to come. By following the natural cycle of the seasons—waiting for the frost, curing the rhizomes, and providing a cool, stable winter home—you can ensure your garden remains a vibrant, colorful space summer after summer.
At Longfield Gardens, we believe that gardening should be a rewarding and accessible experience. Saving your own rhizomes is not only a great way to save money, but it also allows you to grow bigger, more established plants each year. We stand behind the quality of our plants with a 100% quality guarantee, and we are here to support you as you grow your garden. Learn more in our 100% Quality Guarantee.
- Wait for the first frost to signal that it is time to dig.
- Cure the rhizomes for a few days to toughen the skin and prevent rot.
- Store in a cool, dark place between 45°F and 55°F using a breathable medium like peat moss or wood shavings.
- Check monthly to ensure the rhizomes stay firm and healthy throughout the winter.
Storage is simply a way to hit the "pause" button on your garden. When spring returns, your cannas will be ready to wake up and transform your yard once again.
FAQ
Do I have to wash the dirt off canna rhizomes before storing them?
While some gardeners like to wash them to see the eyes more clearly, it isn't strictly necessary. Many successful gardeners simply shake off the loose soil and leave a small amount of dirt, which can help prevent the rhizome from drying out too quickly during the winter.
Can I store cannas in a refrigerator?
While a refrigerator is cool and dark, it is usually too cold and lacks the proper humidity for canna rhizomes. Temperatures in a fridge are typically set around 35-38°F, which can damage the tender tropical tissue over a long period. A cool basement or crawl space is a much better option.
What happens if I don't dig up my cannas?
If you live in USDA Zone 8 or warmer, your cannas may survive the winter in the ground with a thick layer of mulch. However, in Zone 7 and colder, the ground usually freezes deep enough to reach the rhizomes, which will cause them to turn to mush and die. In these areas, digging is essential for survival. If you are not sure which zone you garden in, check the Hardiness Zone Map.
Why did my stored canna rhizomes turn mushy?
Mushiness is usually a sign of rot, which is caused by either poor airflow, excess moisture during storage, or damage from freezing temperatures. To prevent this, ensure your rhizomes are cured (dried) for a few days before packing and check that your storage container has plenty of ventilation holes.