Table of Contents
- Introduction
- Understanding Canna Hardiness
- Timing Your Harvest: The First Frost
- Tools and Preparation
- Step-By-Step: Digging Your Canna Rhizomes
- Cleaning and Curing the Rhizomes
- Choosing the Right Storage Medium
- Finding the Perfect Winter Home
- Monitoring During the Winter
- Special Advice for Container-Grown Cannas
- Dividing for More Plants
- Preparing for a Successful Spring
- Conclusion
- FAQ
Introduction
There is something truly special about the lush, tropical feel that cannas bring to a summer landscape. With their oversized, paddle-shaped leaves and vibrant, orchid-like blooms, they turn any backyard into a vacation destination. These plants are remarkably easy to grow, but because they are tropical by nature, they need a little extra care to survive the cold months in many parts of the country.
Learning how to store canna bulbs through the winter is one of the most rewarding skills you can add to your gardening toolkit. By taking a few simple steps in the fall, you can save your favorite varieties and enjoy even larger, more beautiful displays every year. At Longfield Gardens, we want to make sure you feel confident and excited about keeping your garden favorites healthy from one season to the next.
This guide will walk you through the entire process, from the first frost of autumn to the final packing steps. Whether you have a single pot on your patio or a long border of tall cannas, these techniques will help you preserve your plants with ease. Storing your cannas correctly ensures that your garden will be ready to burst into color as soon as the warm weather returns.
Understanding Canna Hardiness
Cannas are native to warm climates, which means they thrive in heat and humidity but are sensitive to freezing temperatures. In the world of gardening, we talk about hardiness zones to help determine which plants can stay outside all winter. For cannas, the rules of thumb are straightforward and help you decide whether digging is necessary.
In USDA hardiness zones 8 through 11, cannas are often able to stay in the ground year-round. In these warmer regions, the soil rarely freezes deep enough to damage the underground structures. Gardeners in these areas usually just cut the stalks back and perhaps add a fresh layer of mulch for a little extra insulation.
However, for those of us in zones 7 and colder, the winter chill is a bit too much for cannas to handle outdoors. In these climates, the fleshy parts of the plant would freeze and rot if left in the garden. By digging them up and moving them to a protected spot, we can keep them in a dormant state—basically a long winter nap—until spring.
While the common term is "canna bulbs," these plants actually grow from rhizomes. A rhizome is a thick, fleshy underground stem that stores energy for the plant. Because these stems are full of moisture and nutrients, they are sensitive to the cold but very easy to store once you know the basics. For a broader overview, see All About Cannas.
Timing Your Harvest: The First Frost
The best time to start the storage process is closely tied to the weather. You do not need to rush to dig your cannas as soon as the kids go back to school or the first autumn leaf falls. In fact, cannas benefit from staying in the ground as long as possible.
As the days get shorter and the air turns crisp, cannas continue to move energy from their leaves down into their rhizomes. This energy storage is what fuels the spectacular growth and blooming you see the following summer. Waiting until the end of the season ensures that your rhizomes are as large and healthy as they can be.
The ideal signal to start digging is the first light frost. You will know it has happened when the lush green foliage of your cannas turns dark brown or black overnight. While the leaves might look a bit sad after a frost, this is actually a helpful part of the process. The frost tells the plant that it is time to go dormant.
If you live in an area where a hard freeze (where the ground begins to freeze solid) happens quickly after the first frost, try to get your cannas out of the ground within a few days of that first cold snap. The goal is to dig them while the soil is still workable and before the rhizomes themselves are exposed to freezing temperatures under the soil.
Key Takeaway: Wait for the first light frost to blacken the leaves before digging. This natural signal tells the plant to move its energy into the rhizomes for winter storage.
Tools and Preparation
Before you head out to the garden, gathering a few simple tools will make the job much faster and more enjoyable. You don't need heavy machinery; most home gardeners already have everything they need in the shed.
- A sturdy garden fork or spade: A garden fork is often the preferred tool for digging rhizomes because it is less likely to slice through the fleshy stems than a flat shovel.
- Garden shears or loppers: You will need these to cut back the heavy stalks.
- A garden hose: This is helpful for rinsing off excess soil, though some gardeners prefer to let the soil dry and brush it off.
- Labels and a waterproof marker: This is perhaps the most important tool. Many cannas look identical once they are just bare rhizomes, so labeling them now prevents confusion in the spring.
- Storage containers: Cardboard boxes, plastic bins with air holes, or even breathable burlap bags all work well.
Having your supplies ready allows you to move through the process efficiently, ensuring your cannas spend the minimum amount of time exposed to the elements between the soil and their winter home.
Step-By-Step: Digging Your Canna Rhizomes
When you are ready to dig, the most important thing is to be gentle. Think of this as a harvest rather than a demolition project. Follow these simple steps for a successful dig:
1. Cut Back the Foliage
Start by cutting the stalks down to about 2 to 4 inches above the soil line. Removing the bulky leaves and stems makes the plant much easier to handle. Leaving a small "handle" of the stalk attached to the rhizome gives you something to hold onto and helps you identify which side is "up" later on.
2. Loosen the Soil
Position your garden fork or spade about 6 to 10 inches away from the base of the stalks. Cannas grow outward, so the rhizomes may have spread further than you think. Push the tool deep into the soil and gently pry upward. Work your way around the entire clump, loosening the earth as you go.
3. Lift the Clump
Once the soil is loose all the way around, gently lift the entire mass of rhizomes out of the ground. You might be surprised at how much they have grown! A single canna planted in the spring can turn into a large, heavy clump by autumn. If the clump is too heavy to lift all at once, you can gently use your spade to divide it into two or three manageable pieces while it is still in the ground.
4. Shake Off Excess Dirt
Hold the clump by the remaining stalks and gently shake it to remove the bulk of the garden soil. You can also use your hands to brush away large clods of earth. Don't worry about getting them perfectly clean just yet; the goal is simply to make them light enough to move to your cleaning station.
What to Do Next:
- Cut stalks to 2-4 inches.
- Dig wide to avoid cutting the rhizomes.
- Lift the whole clump gently.
- Shake off the heaviest soil.
Cleaning and Curing the Rhizomes
Once the cannas are out of the ground, they need a little preparation before they go into long-term storage. For a fuller overview, see Winter Storage for Summer Bulbs and Tubers. This phase is often called "curing," and it is a vital step in preventing rot.
To Wash or Not to Wash?
There are two schools of thought on cleaning cannas. Some gardeners prefer to use a garden hose to wash every bit of soil off the rhizomes. This makes it easier to inspect them for any signs of damage or pests. Other gardeners prefer to let the soil dry for a day and then simply brush off the loose dirt.
Either method works well. If you choose to wash them with water, just be sure to let them dry thoroughly afterward. Moisture is the biggest challenge during winter storage, so starting with a dry surface is key.
The Curing Process
Curing is simply letting the rhizomes sit in a protected, dry area for a few days. This allows the outer skin to toughen up slightly, which helps the rhizome retain its internal moisture while resisting external mold.
Place your cleaned rhizomes in a single layer on a piece of cardboard or a mesh screen. A garage, a covered porch, or a garden shed are perfect spots. Avoid leaving them in direct sunlight, as this can cause them to overheat or dry out too quickly. Ideally, you want a spot with good air circulation and temperatures between 60°F and 70°F. Let them cure for two to four days until the surfaces feel dry to the touch and any remaining soil is crumbly.
Inspection and Trimming
While your cannas are curing, take a moment to inspect them. Look for any soft spots or areas that look damaged. If you find a small soft spot, you can usually trim it away with a clean knife. If a rhizome feels mushy or smells sour, it is best to discard it so it doesn't affect the healthy ones. You can also trim away any long, stringy roots that are hanging off the bottom of the rhizomes, though this isn't strictly necessary.
Choosing the Right Storage Medium
How you pack your cannas depends on the environment where you will be storing them. The goal is to keep them "just right"—not so wet that they rot, but not so dry that they shrivel up like a raisin. To achieve this balance, we use a storage medium to surround the rhizomes.
Peat Moss or Coir
Peat moss is one of the most popular choices for storing canna bulbs. It is naturally sterile and does a great job of absorbing excess moisture while still providing a little humidity. Coconut coir is a wonderful, sustainable alternative that works in the same way. Simply place a layer of slightly damp (but not wet) peat or coir in the bottom of your container, nestle the rhizomes in, and cover them with more material.
Wood Shavings
If you have a basement or storage area that tends to be a bit damp, wood shavings (the kind sold for animal bedding) are an excellent choice. They allow for more airflow than peat moss, which helps prevent rot in humid environments. They are also very lightweight and easy to handle in the spring.
Newspaper
For a very simple approach, you can wrap individual rhizomes in a few sheets of dry newspaper. Then, layer the wrapped bundles in a cardboard box. The newspaper acts as a buffer, preventing one rhizome from touching another. This is helpful because if one happens to develop a soft spot, the newspaper prevents it from spreading to its neighbors.
Plastic Bags
In very dry homes, some gardeners have success using plastic bags. If you use this method, it is essential to poke plenty of air holes in the bag to allow for ventilation. You should also add a bit of peat moss or wood shavings inside the bag to regulate moisture. Without air holes, the moisture from the rhizomes will condense on the plastic and cause them to rot quickly.
Key Takeaway: The storage medium acts as insulation and moisture control. Choose peat moss for dry areas and wood shavings or newspaper for more humid spots.
Finding the Perfect Winter Home
Once your cannas are packed, they need a place to stay until spring. The ideal storage location is cool, dark, and dry.
Temperature Matters
The sweet spot for storing canna rhizomes is between 45°F and 55°F. If the temperature stays in this range, the plants will remain perfectly dormant. If the storage area gets too cold (below 40°F), there is a risk of the rhizomes freezing. If the area is too warm (above 60°F), the cannas might think it is spring and start to grow prematurely in the dark, which uses up their stored energy.
Common Storage Locations
- Unheated Basements: Often the most reliable spot for many gardeners. Basements usually stay cool and have relatively stable humidity.
- Crawl Spaces: These can be great as long as they stay above freezing and are not prone to flooding.
- Attached Garages: A garage can work, but you must be careful. Often, the floor of a garage can get much colder than the rest of the space. It is a good idea to keep your storage boxes up on a shelf or a pallet rather than directly on the concrete.
- Root Cellars: If you are lucky enough to have one, this is the gold standard for storing any kind of dormant bulb or rhizome.
Regardless of where you put them, make sure the spot is dark. Light can encourage the rhizomes to start sprouting before you are ready to plant them.
Monitoring During the Winter
Storing cannas is not a "set it and forget it" task. To ensure the best results, we recommend checking on your rhizomes about once a month. This small habit only takes a few minutes but can save your entire collection.
When you check your boxes, look for two things:
1. Signs of Rot
If you see any rhizomes that look fuzzy, feel mushy, or have a bad odor, remove them immediately. By taking out the "bad apples" early, you protect the rest of the batch. This is why using newspaper or individual wrapping can be so helpful.
2. Signs of Shriveling
If the rhizomes look very wrinkled or feel extremely light and hollow, they are getting too dry. You can remedy this by using a spray bottle to lightly mist the storage medium (the peat moss or shavings) with a little water. You don't want to soak the rhizomes; you just want to add a tiny bit of humidity back into the box.
Most of the time, you will find that your cannas are sitting quietly, waiting for the sun. If they look the same as they did when you packed them, you are doing a great job!
Special Advice for Container-Grown Cannas
If you grow your cannas in pots, Short Cannas are especially easy to manage. Many gardeners find it easier to store the entire pot rather than digging the rhizomes out of the soil.
After the first frost has blackened the foliage, cut the stalks back to just above the soil line as you normally would. Then, simply move the entire pot into a cool, frost-free area like a basement or garage. The soil in the pot acts as a natural storage medium, keeping the rhizomes insulated and holding just enough moisture.
How to Grow Summer Bulbs in Containers is a helpful next step if you want to grow more of these plants in pots. In the spring, about six weeks before the last frost, you can bring the pots back out into the light and start watering them. This gives you a significant head start on the season, and you may find your potted cannas blooming much earlier than those planted directly in the garden. Just remember that cannas are fast growers; eventually, they will become crowded in the pot and will need to be divided every year or two to keep them healthy.
Dividing for More Plants
One of the most exciting things about cannas is how much they multiply. A single rhizome can easily produce three to five new growing points over the course of a summer. This means you can gradually fill your entire garden—or share plants with friends and neighbors—starting from just a few initial bulbs. The Canna Medium Banana Punch is a good example of the kind of lively canna that works well in many garden spaces.
While you might be tempted to divide your clumps in the fall when you dig them, we generally recommend waiting until spring. In the spring, it is much easier to see the "eyes" (the small bumps or sprouts where new growth will emerge).
When you are ready to plant in the spring, use a clean knife to cut the rhizomes into pieces. Ensure each piece has at least one or two healthy-looking eyes. Let the cut surfaces dry for a day before planting to prevent rot. This simple process of division is the secret to a massive, colorful garden on a budget.
Preparing for a Successful Spring
As the winter begins to fade and the first signs of spring appear, you can start thinking about bringing your cannas out of storage. In most areas, you can plant cannas outdoors once the soil has warmed up and all danger of frost has passed. For step-by-step planting instructions, see How to Plant Canna Lily Bulbs.
If you want to get a head start, you can "wake up" your cannas indoors about 4 to 6 weeks before your last frost date. Simply plant the rhizomes in pots with potting soil and place them in a sunny window or under grow lights. By the time it is warm enough to move them outside, you will already have several inches of lush green growth.
Our team works with trusted growers to ensure all the cannas we offer are top-quality. We stand behind our plants with confidence, so you can plant knowing your items are true to variety and ready to perform.
Conclusion
Storing canna bulbs through the winter is a simple, satisfying process that bridges the gap between garden seasons. By following the natural cues of the frost and providing a cool, stable environment, you can preserve the tropical beauty of your garden for years to come. It is a wonderful way to connect with the cycle of growth and ensure that your yard remains a vibrant, welcoming space every summer.
- Wait for the first frost to signal dormancy.
- Cure rhizomes for a few days to toughen the skin.
- Store in a cool, dark place between 45°F and 55°F.
- Check monthly for moisture balance and health.
Storing your own canna rhizomes is one of the easiest ways to grow a bigger, better garden every year without starting from scratch.
When you're ready to add new colors and textures to your landscape, we invite you to explore the Canna Assorted Collection at Longfield Gardens.
Whether you are looking for dramatic foliage or brilliant blooms, we invite you to explore Shop by Color - Spring-Planted Bulbs.
FAQ
Do I have to dig up my cannas every year?
It depends on your location. If you live in USDA zone 8 or warmer, you can usually leave cannas in the ground with a layer of mulch for protection. If you live in zone 7 or colder, you must dig them up and store them indoors to prevent the rhizomes from freezing and rotting over the winter. If you're not sure where you fall, check the Hardiness Zone Map.
What happens if I dig my cannas before the first frost?
You can certainly dig them earlier if your schedule requires it, but they may not have stored as much energy as those that stayed in the ground until frost. If you dig early, just make sure the plants have had a full growing season to develop large, healthy rhizomes before you start the curing and storage process.
Can I store canna rhizomes in a refrigerator?
While a refrigerator is cool and dark, it is usually too cold and lacks the proper humidity for canna storage. The temperature in a fridge is typically around 35°F to 38°F, which can damage the tropical tissues of the rhizome. A cool basement or insulated garage is a much better choice for maintaining the ideal 45°F to 55°F range.
My stored cannas have started to sprout in February. What should I do?
If your cannas start to sprout early, it usually means their storage area is a bit too warm. If the sprouts are small (less than an inch), you can try moving them to a slightly cooler spot to slow them down. If they are growing vigorously, your best bet is to plant them in pots and grow them as houseplants until it is warm enough to move them outside. For more on container growing, see the container growing guide.