Table of Contents
- Introduction
- Understanding Canna Rhizomes
- When Is the Right Time to Dig?
- Preparing the Plants for Digging
- The Best Tools for the Job
- Step-by-Step: How to Dig Canna Rhizomes
- Cleaning and Curing Your Cannas
- Should You Divide Your Cannas Now?
- Choosing Your Storage Medium
- The Best Way to Pack Your Cannas
- The Ideal Storage Environment
- Monthly Maintenance: The Winter Check-up
- Storing Container-Grown Cannas
- Preparing for Spring
- Why Quality Matters
- Conclusion
- FAQ
Introduction
There is nothing quite like the tropical transformation cannas bring to a summer garden. With their lush, banana-like leaves and vibrant, orchid-inspired blooms, these plants turn any backyard into a vacation destination. Whether you grow them in large containers on the patio or as a bold backdrop in your garden beds, cannas are reliable performers that provide months of high-impact color.
As the season winds down and the first crisp evenings of autumn arrive, it is time to think about preserving that beauty for next year. While cannas are tropical plants, they are incredibly easy to save if you live in a climate with freezing winters. At Longfield Gardens, we want to help you enjoy your favorite canna varieties year after year by mastering a few simple end-of-season steps.
In this guide, we will walk you through the straightforward process of lifting, cleaning, and storing your canna rhizomes. This process is perfect for home gardeners who want to expand their collection without starting from scratch every spring. For more on winter storage, you can ensure your cannas stay healthy and dormant until it is time to plant them again.
Understanding Canna Rhizomes
Before you pick up a shovel, it helps to understand what you are actually digging up. Although many people refer to them as "bulbs," canna rhizomes grow from thick, fleshy underground stems called rhizomes. These rhizomes act like a storage battery for the plant. Throughout the summer, the large leaves soak up sunlight and convert it into energy, which is then sent down into the rhizome.
This stored energy is what allows the plant to sprout quickly and grow several feet tall in a single season. The goal of winter storage is to keep that "battery" charged and healthy while the plant is dormant. If the rhizomes freeze, the water inside their cells expands and destroys them. If they get too wet during the winter, they can rot. Our goal is to find the perfect middle ground: a cool, dark, and slightly dry environment.
Most cannas are hardy in USDA zones 8 through 11, meaning they can stay in the ground year-round in those warm climates. However, if you live in zone 7 or colder, digging them up is the best way to guarantee they return. Even in zone 7, where they might survive a mild winter with heavy mulching, lifting them offers peace of mind and an opportunity to divide the plants. For the most up-to-date USDA Hardiness Zone Map, check your local zone before deciding whether to dig them.
When Is the Right Time to Dig?
Timing is one of the most important parts of successful canna storage. You want to give the plants as much time as possible to store energy, but you must get them out of the ground before the soil itself freezes solid.
The best signal to start the process is the first frost of the season. A light frost will usually turn the lush green leaves to a dark brown or black. While this might look disappointing, it is actually a helpful "off switch" for the plant. The frost tells the canna that the growing season is over and it is time to go dormant.
If you live in an area where frost comes very late, you can still dig your cannas in late autumn once the temperatures consistently stay below 50°F. The plants will naturally begin to yellow and slow down their growth. Waiting for that first light frost is the traditional method, as it ensures the plant has finished its energy-storage cycle for the year.
Key Takeaway: Wait for the first frost to blacken the foliage before digging. This signal ensures the plant has stored maximum energy in its rhizome for next year’s growth.
What to Do Next:
- Keep an eye on your local weather forecast for the first "killing frost."
- Gather your supplies: a garden fork or spade, pruning shears, and storage containers.
- Check your garden labels to make sure you know which variety is which before the foliage dies back.
Preparing the Plants for Digging
Once the foliage has been hit by frost, your first task is to clear away the dead growth. This makes the digging process much cleaner and allows you to see exactly where the base of the plant is.
Using a sharp pair of pruning shears or a garden knife, cut the stalks down to about 2 to 4 inches above the soil line. You don't want to cut them completely flush with the ground, as leaving a short "handle" makes it easier to move the clumps and helps you identify which end is up later on.
Discard the frost-damaged leaves and stems. While you can compost them if they are healthy, it is often better to dispose of them if you noticed any pests like canna leaf rollers during the summer. This prevents any dormant pests from sticking around in your compost pile.
The Best Tools for the Job
Choosing the right tool can make the work much easier and prevent damage to the rhizomes. While a standard pointed shovel (spade) works, a garden fork (also called a digging fork) is often the superior choice for lifting cannas.
The tines of a garden fork can slide through the soil with less resistance than a solid shovel blade. This reduces the chance of accidentally slicing through a large rhizome clump. If you do use a shovel, be sure to give the plant plenty of "breathing room" by digging further away from the center than you might think necessary.
Step-by-Step: How to Dig Canna Rhizomes
Digging cannas is a satisfying task because you are often surprised by how much the plants have grown beneath the surface. A single rhizome planted in May can turn into a massive clump by October.
Step 1: Loosen the Soil
Start by inserting your fork or spade into the soil about 6 to 10 inches away from the base of the stalks. You want to avoid hitting the fleshy rhizomes. Dig in a circle all the way around the clump, pushing the tool deep into the ground and gently rocking it back and forth to loosen the roots.
Step 2: Lift the Clump
Once you have loosened the soil around the entire perimeter, slide your tool underneath the center of the clump. Use the tool as a lever to gently pry the mass upward. If the clump is very large, you might need to do this from several sides. Lift the entire root mass out of the ground.
Step 3: Shake Off Excess Soil
Cannas have a very dense, fibrous root system that holds onto soil tightly. While the clump is still fresh from the ground, give it a gentle shake or use your hands to brush away the loose dirt. Don't worry about getting them perfectly clean just yet; the goal is simply to make them light enough to carry to your workspace.
Step 4: Inspect for Health
As you dig, keep an eye out for any rhizomes that feel soft, mushy, or show signs of significant rot. Healthy rhizomes should feel firm, similar to a fresh potato. If you find any damaged sections, you can cut them away now or wait until you have cleaned them more thoroughly.
Key Takeaway: Dig wide and deep to avoid cutting the rhizomes. A garden fork is the gentlest tool for lifting large clumps without causing damage.
Cleaning and Curing Your Cannas
After digging, the next phase is preparing the rhizomes for their long winter nap. This involves cleaning and "curing," which is a fancy gardening term for letting the outside of the rhizome dry out slightly so it doesn't rot in storage.
Washing vs. Brushing
There are two schools of thought on cleaning cannas. Some gardeners prefer to use a garden hose to wash all the soil off the rhizomes. This makes it very easy to see the "eyes" (growth points) and check for pests. If you choose to wash them, you must be very diligent about drying them afterward.
The second method is to let the soil dry for a few hours and then brush it off with a soft brush or your gloved hands. This method is often safer for beginners because it introduces less moisture into the process. Excessive moisture is the primary cause of rot during winter storage.
The Curing Process
Curing is a vital step that many people skip. Once the rhizomes are mostly clean, lay them out in a single layer in a frost-free, well-ventilated area. A garage, garden shed, or a covered porch works well. Avoid placing them in direct sunlight, as this can cause them to shrivel too quickly.
Let the rhizomes air dry for 2 to 7 days. During this time, the outer skin will toughen up slightly, and any remaining soil will become crumbly and easy to remove. This "toughening" act creates a natural barrier against disease and moisture loss.
Should You Divide Your Cannas Now?
One of the most rewarding parts of growing cannas is that they multiply. When you dig them up in the fall, you will likely have three or four times as many plants as you started with. You can divide these clumps either in the fall after cleaning or in the spring before replanting.
We often recommend waiting until spring to do the heavy dividing, as it gives you more options. However, if your clumps are too large to store easily, you can break them into smaller pieces now.
To divide them, look for the "eyes"—these are the small, rounded bumps on the rhizome where new stems will grow. Ensure each piece you break off has at least two or three healthy eyes and a good portion of the fleshy rhizome attached. Use a clean, sharp knife to make the cuts, and let the cut ends dry for a day before packing them away.
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 helps maintain a very slight amount of moisture while allowing the plant to breathe. If the environment is bone-dry, the rhizomes will shrivel and die. If it is soaking wet, they will rot.
Here are the most successful materials to use for storage:
- Peat Moss: This is the most popular choice. It holds a tiny bit of moisture but is naturally anti-fungal. Use slightly damp (not wet) peat moss to surround the rhizomes.
- Wood Shavings or Sawdust: Large cedar or pine shavings (like the kind used for pet bedding) provide excellent airflow while preventing the rhizomes from touching each other.
- Vermiculite or Perlite: These lightweight minerals are great for moisture control and are very clean to work with.
- Newspaper: If you are on a budget, wrapping each individual rhizome in several layers of dry newspaper is an effective and traditional method.
The Best Way to Pack Your Cannas
Once your rhizomes are cured and you have chosen your medium, it is time to pack them away. We recommend using cardboard boxes, plastic totes with the lids left cracked open, or milk crates. Avoid airtight containers, as the rhizomes are living things that need a small amount of oxygen.
- Layering: Place a 2-inch layer of your chosen medium (like peat moss) at the bottom of the container.
- Placement: Lay the rhizomes on top of the medium. Do not let them touch each other. This ensures that if one rhizome happens to rot, the problem won't easily spread to the others.
- Covering: Add another layer of medium until the rhizomes are completely covered.
- Labeling: This is a crucial step! It is very easy to forget which box contains the "Red Futurity" and which has the Pretoria once the leaves are gone. Write the variety name and the flower color on the outside of the box or place a plastic label inside.
What to Do Next:
- Choose a storage container that allows for some airflow.
- Lightly mist your peat moss or shavings so they feel barely damp to the touch.
- Double-check that every box is clearly labeled with the variety name.
The Ideal Storage Environment
Location is everything when it comes to winter storage. Cannas need a spot that stays consistently cool but never reaches freezing temperatures.
The ideal temperature range is between 45°F and 55°F. If the temperature drops below 40°F, you risk damaging the plant tissues. If the temperature stays above 60°F, the cannas might think it is spring and start to grow in the dark, which depletes their energy.
Great storage locations include:
- Unheated Basements: Usually the most consistent environment.
- Root Cellars: Naturally humid and cool.
- Crawl Spaces: As long as they are dry and frost-free.
- Attached Garages: Be careful here; some garages can get too cold during a polar vortex. If using a garage, keep the boxes on an inner wall and off the concrete floor.
Monthly Maintenance: The Winter Check-up
Storing cannas isn't a "set it and forget it" task. To ensure a high success rate, you should check on your boxes once a month throughout the winter. This only takes a few minutes but can save your entire collection.
Open the boxes and feel a few of the rhizomes.
- If they feel shriveled or very dry: The storage medium has lost too much moisture. Use a spray bottle to lightly mist the medium. Do not soak it; just add enough moisture to dampen the air around the plants.
- If they feel soft, mushy, or smell bad: This is a sign of rot. Immediately remove any affected rhizomes and throw them away. Check the surrounding medium to make sure it isn't too wet.
- If you see sprouts: The storage area is too warm. Move the boxes to a cooler spot to keep them in dormancy until spring.
Key Takeaway: A quick monthly check is the secret to success. Maintaining the balance between "too dry" and "too wet" ensures your cannas arrive in spring ready to grow.
Storing Container-Grown Cannas
If you grow your container-grown cannas in large pots, you have a shortcut available. You don't necessarily have to dig the rhizomes out of the soil.
After the first frost, cut the stalks back as you would for garden-grown plants. Move the entire container into a cool, frost-free area like a basement or garage. Stop watering the pot entirely. The soil will dry out, and the plant will go dormant. In the spring, you can simply bring the pot back into the sun, start watering, and wait for the new shoots to appear.
Keep in mind that cannas grow very quickly. After one or two years of this "pot storage" method, the rhizomes will likely become crowded and will need to be removed, divided, and replanted with fresh soil to keep the plant healthy and blooming well.
Preparing for Spring
When the days begin to lengthen and the threat of frost passes, it is time to wake up your cannas. Most gardeners begin checking their stored rhizomes in late March or April.
If you want an early start, you can plant your rhizomes in pots indoors about 4 to 6 weeks before the last frost date. This gives them a head start so they are already a few inches tall by the time the outdoor soil is warm enough for planting. If you prefer to plant directly in the ground, wait until the soil temperature reaches at least 60°F. Cannas love heat, and they won't do much until the ground is warm and cozy.
At our trial garden at Longfield Gardens, we have found that being patient with spring planting leads to much better results. Planting in cold, wet spring soil can lead to slow growth or even rot. Wait for those warm, sunny days to ensure your cannas hit the ground running.
Why Quality Matters
While storing your own rhizomes is a great way to save money and keep your favorite plants, sometimes you might want to add new colors or textures to your garden. When buying new cannas, always look for firm, heavy rhizomes with visible eyes.
We take great pride in the quality of the plants we provide. Every order is backed by our 100% quality guarantee. We ensure that your items are true to variety and arrive in prime condition for planting. If you ever have a concern about the performance of your plants in their first growing season, we are here to help with replacements or credits to ensure your gardening experience is a success.
Conclusion
Digging and storing canna rhizomes is a simple, rewarding tradition that connects you to the cycle of the seasons. It turns a one-time purchase into a lifetime of tropical beauty. By waiting for the first frost, curing the rhizomes properly, and finding a cool, dark corner for them to rest, you are setting the stage for another spectacular summer display.
The effort required is minimal compared to the joy of seeing those first red, orange, or yellow blooms emerge next July. Gardening is about the long game, and successfully overwintering your plants is one of the most satisfying "easy wins" a home gardener can achieve.
- Wait for frost to signal dormancy.
- Cure rhizomes for a few days to toughen the skin.
- Store in a breathable medium like peat moss or wood shavings.
- Check monthly for moisture balance.
"Preserving your cannas is not just about saving a plant; it's about carrying the warmth and color of summer into the next year."
We invite you to explore the many beautiful canna varieties available at Longfield Gardens to expand your tropical oasis. Whether you are a beginner or a seasoned pro, we are here to support you with quality plants and practical advice every step of the way.
FAQ
How long can canna rhizomes stay in the ground after a frost?
It is best to dig them up within a week or two after the first frost. While the rhizomes are safe as long as the ground doesn't freeze, waiting too long increases the risk of soil-borne rot if the autumn weather is particularly wet.
Can I store my cannas in a plastic bag?
You can use plastic bags, but they must have several large air holes punched in the sides. Without airflow, moisture will become trapped against the rhizome, which almost always leads to rot. A cardboard box or an open bin is generally a safer choice for beginners.
What should I do if my stored rhizomes look wrinkled in January?
Wrinkling is a sign that the rhizomes are dehydrating. Use a spray bottle to lightly mist the storage medium (the peat moss or shavings) with water. This increases the humidity in the box and helps the rhizomes plump back up without making them wet enough to rot.
Do I need to treat the rhizomes with fungicide before storing?
For most home gardeners, a fungicide is not necessary if the rhizomes are properly cured and stored in a clean medium like peat moss. Ensuring the rhizomes are dry to the touch and that any damaged parts are cut away before storage is the most effective way to prevent disease naturally.