Table of Contents
- Introduction
- Determining When to Dig Your Cannas
- Preparing the Plants for Digging
- How to Dig Canna Rhizomes Carefully
- Cleaning and Curing the Rhizomes
- Dividing Canna Rhizomes
- Choosing the Right Storage Container
- Packing Materials for Moisture Control
- Finding the "Goldilocks" Storage Spot
- Storing Potted Cannas
- Mid-Winter Checkups
- Preparing for Spring Replanting
- Common Myths About Canna Storage
- The Longfield Gardens Quality Promise
- Conclusion
- FAQ
Introduction
There is nothing quite like the tropical flair that canna lilies bring to a summer garden. Their bold, paddle-shaped leaves and vibrant, jewel-toned flowers make any backyard feel like a private island getaway. At Longfield Gardens, we love how these fast-growing cannas transform a landscape in just one season.
While cannas are tropical at heart, you do not have to live in a warm climate to enjoy them every summer. Storing canna bulbs—which are technically called rhizomes—is a straightforward process that allows you to save your favorite varieties and even increase your plant collection for free. Whether you are a beginner or have been gardening for years, this guide will walk you through the simple steps to keep your cannas safe and sound through the winter months.
This post covers everything from the first frost to spring replanting, ensuring your cannas return even bigger and better next year. By following these practical steps, you can protect your investment and enjoy a lush, colorful garden every summer.
Determining When to Dig Your Cannas
The most important part of successful canna bulb storage is timing. While it can be tempting to start cleaning up the garden as soon as the weather turns chilly, cannas benefit from staying in the ground as long as possible. The longer they remain in the soil, the more energy the rhizomes can store for next year’s growth.
The First Frost Signal
In most regions, the signal to begin the storage process is the first light frost of autumn. You will know it has happened when the lush green or bronze foliage of your cannas turns black or a dull, crispy brown. This may look a bit sad at first, but it is actually a helpful sign from nature. The frost tells the plant to stop sending energy to the leaves and to focus entirely on the underground rhizomes.
Wait until this frost has occurred before you reach for your shovel. If you dig them up while the leaves are still bright green and growing, you might miss out on that final boost of stored energy. However, do not wait too long. You want to get the rhizomes out of the ground before the soil itself freezes solid. A light surface frost won't hurt the bulbs, but a deep, hard freeze that penetrates the soil can cause the watery tissues of the rhizome to turn to mush.
Knowing Your Hardiness Zone
Your local weather and USDA hardiness zone will determine if you even need to dig your bulbs at all.
At Longfield Gardens, we recommend checking your zone to make the best decision for your plants.
- Zones 8 to 10: In these warmer regions, cannas are generally hardy. You can leave them in the ground year-round. Simply cut the foliage back to the ground after it fades and perhaps add a layer of mulch for protection.
- Zone 7: This is a "swing" zone. In mild winters, cannas may survive with heavy mulching. However, many gardeners choose to dig them up just to be safe, especially if they have a prized variety.
- Zones 3 to 6: In these colder climates, the ground will freeze deep enough to kill canna rhizomes. Digging and storing them indoors is essential if you want to see them again next spring.
Key Takeaway: The best time to dig cannas is right after the first light frost has blackened the leaves, but before the ground freezes hard. This timing ensures the plant has stored maximum energy for the following season.
Preparing the Plants for Digging
Before you start digging, you need to prepare the "top side" of the plant. This makes the underground portion much easier to manage.
Cutting Back the Foliage
Once the frost has hit, take a pair of sharp garden pruners or a small garden saw and cut the stalks down. You should leave about 2 to 4 inches of stem protruding from the ground. These short "handles" serve two purposes: they show you exactly where the center of the root mass is located, and they provide a convenient way to lift the clump without damaging the fragile growing points on the rhizome.
Discard the blackened foliage in your compost pile or yard waste bin. By removing the bulky leaves now, you make the digging process much cleaner and less cumbersome.
Identifying the Root Structure
It is helpful to understand what you are looking for under the soil. A canna bulb is actually a rhizome, which is a thick, fleshy horizontal stem that grows underground. Over the course of a single summer, one small rhizome can grow into a massive, heavy clump. Expect the root mass to be significantly larger than what you planted in the spring.
How to Dig Canna Rhizomes Carefully
Digging is the most physical part of the process, but it is very rewarding to see how much your plants have multiplied. The goal is to lift the entire clump without slicing through the fleshy rhizomes.
Step 1: Choose the Right Tools
A garden fork is often the best tool for this job. The tines can slide into the soil and lift the roots with less risk of cutting the rhizomes than a flat-bladed shovel. However, if your soil is very heavy clay, a sturdy spade will also work well.
Step 2: Create a Wide Perimeter
Canna rhizomes spread outward as they grow. To avoid accidental damage, start digging about 10 to 12 inches away from the base of the stems. If you dig too close, you are likely to chop off the newest, healthiest parts of the plant.
Step 3: Loosen and Lift
Insert your fork or spade deeply into the soil all the way around the plant. Gently rock the tool back and forth to loosen the earth. Once you have circled the entire clump, slide your tool underneath the center and lift the mass upward.
If the clump is particularly large and heavy, don't be afraid to ask for a hand or to gently break the clump into two smaller pieces while it is still in the hole. This makes it much easier to carry to your cleaning station.
What to Do Next: Digging Checklist
- Cut stems to 2–4 inches above the soil line.
- Clear away dead foliage to see the base clearly.
- Use a garden fork to dig a wide circle around the plant.
- Gently pry the root mass upward from beneath.
- Lift the clump by the soil/root base, using the stems only for minor guidance.
Cleaning and Curing the Rhizomes
Once the cannas are out of the ground, they need a little bit of "spa time" before they go into storage. Cleaning and curing are the two most important steps for preventing rot during the winter.
Removing Excess Soil
Gently shake the clump to remove large chunks of soil. You can use your hands to brush away loose dirt, but be careful not to skin the rhizomes. The "skin" of a fresh rhizome is quite thin and easily bruised.
Some gardeners prefer to wash their cannas with a garden hose to get them perfectly clean. This is fine, but it adds a lot of moisture to the plant. If you choose to wash them, you must be extra diligent about the drying process that follows. If you have sandy soil, simply shaking and brushing them is usually enough.
The Importance of Curing
"Curing" is simply the process of letting the rhizomes air-dry in a protected spot for a few days. This allows the outer skin to toughen up and any small nicks or cuts to "callus" over. A callused rhizome is much more resistant to mold and fungus than a "wet" one.
Place your rhizomes in a single layer on a tray, a piece of cardboard, or a tarp. Choose a spot that is dry, out of the direct sun, and has good air circulation—a garage, a porch, or a shed works perfectly. Let them sit for 7 to 10 days. By the end of this period, any remaining soil should be bone-dry and easy to flick away, and the cut stems should look shriveled and dry.
Dividing Canna Rhizomes
One of the best things about cannas is how much they multiply. You might start the year with three rhizomes and end with fifteen. You can choose to divide them in the fall before you store them, or wait until the spring.
How to Divide
If you decide to divide in the fall, look for the "eyes." These are the small, pointed bumps on the rhizome where new growth will emerge. Use a clean, sharp knife to cut the rhizomes into smaller sections. Each section should have at least one or two healthy-looking eyes and a good portion of the fleshy root attached.
If you make fresh cuts during division, let those pieces cure for an extra day or two so the cut surfaces can dry out before they are packed away.
Choosing the Right Storage Container
How you pack your cannas depends on the space you have available. The goal is to keep them dormant, which means they need to stay cool, dark, and slightly insulated.
Cardboard Boxes and Plastic Tubs
Cardboard boxes are a classic choice because they "breathe," allowing a tiny bit of air exchange which helps prevent moisture buildup. If you use plastic totes, leave the lids slightly ajar or drill a few small holes in the sides for ventilation. If a plastic container is sealed airtight, any remaining moisture will cause the bulbs to rot within weeks.
Paper Bags
For smaller collections, individual paper grocery bags work well. You can put a few rhizomes in each bag with some packing material. This also makes it easy to label your different colors or varieties.
Packing Materials for Moisture Control
You don't want your cannas to sit in a bare box. They need a packing medium to act as a buffer. This material keeps the rhizomes from touching each other (which prevents the spread of rot) and regulates humidity.
Peat Moss and Vermiculite
Peat moss is the gold standard for canna storage. It is naturally acidic, which inhibits fungal growth, and it holds a tiny bit of moisture without feeling "wet." Vermiculite is another excellent choice; it is sterile and provides great insulation.
Wood Shavings and Newspaper
If you have a local pet store, bags of pine or cedar shavings (sold as animal bedding) are inexpensive and work wonderfully. Alternatively, you can use shredded newspaper or even wrap each individual rhizome in a sheet of dry newspaper.
The Packing Process
- Place a 2-inch layer of your chosen material (like peat moss) in the bottom of the box.
- Lay the rhizomes on top, ensuring they are not touching each other.
- Cover them with another layer of material.
- Repeat until the box is full, ending with a thick layer of packing medium on top.
Key Takeaway: Packing materials like peat moss or wood shavings act as a "blanket" for your bulbs. They prevent the rhizomes from drying out completely while also absorbing any excess moisture that could cause rot.
Finding the "Goldilocks" Storage Spot
Location is everything when it comes to overwintering. You need a spot that is cool but not freezing, and dark enough to keep the plants dormant.
The Ideal Temperature Range
Canna rhizomes are happiest when stored between 40°F and 50°F (4°C to 10°C).
- Too Warm: If the temperature stays above 55°F, the rhizomes may think it is spring and start to sprout prematurely in the dark. This wastes the plant's energy.
- Too Cold: If the temperature drops below 35°F, you risk the bulbs freezing, which is fatal.
Suggested Locations
- Unheated Basements: Usually the best option, as they stay cool and humid.
- Root Cellars: Ideal conditions for almost all bulbs and tubers.
- Crawl Spaces: Often stay within the perfect temperature range.
- Attached Garages: Can work, but be careful. Garages can fluctuate wildly in temperature and may drop below freezing during a cold snap.
Storing Potted Cannas
If you grow your cannas in large containers, you have a "short-cut" option. You don't necessarily have to dig them out of the soil.
The "Pot and All" Method
Once the frost has blackened the leaves, cut the stems down to the soil level as usual. Instead of digging, simply move the entire pot into a cool, frost-free area like a basement or garage. Stop watering the pot entirely. The soil in the pot will act as the storage medium.
In the spring, you can pull the pot out, give it a good soak of water, and move it into the sun. However, keep in mind that cannas grow very fast. After a year or two, they will become "root-bound" in the pot. At that point, you will need to tip the pot over, dump everything out, and divide the massive clump of rhizomes to give them more room to grow.
Mid-Winter Checkups
Storing canna bulbs is not a "set it and forget it" task. We recommend checking on your stored bulbs at least once a month during the winter. This five-minute check can save your entire collection.
What to Look For
Open your boxes and feel a few of the rhizomes.
- If they feel soft or mushy: This is a sign of rot. Immediately remove and discard any mushy pieces so the rot doesn't spread to the healthy bulbs.
- If they feel extremely light and shriveled: They might be drying out too much. Use a spray bottle to lightly mist the packing material with water. You don't want it to be wet—just "barely damp" to the touch.
- If you see fuzzy mold: This usually means there isn't enough air circulation. Leave the lid off the box for a few days and perhaps move the container to a slightly drier spot.
Preparing for Spring Replanting
As the days get longer and the ground begins to warm, it is time to start thinking about the garden again. Bringing your cannas out of storage is a simple and exciting process.
Timing the Return
Do not be in a rush to plant cannas outdoors. They are tropical plants and love warm soil. Wait until the danger of frost has completely passed and the soil temperature has reached at least 60°F. In many parts of the US, this is late May or even early June.
Getting a Head Start
If you want blooms earlier in the summer, you can "wake up" your cannas indoors about 4 to 6 weeks before the last frost.
- Remove the rhizomes from their winter boxes.
- Inspect them one last time, discarding any that didn't make it through the winter.
- Plant them in pots with fresh potting soil.
- Place the pots in a warm, sunny window or under grow lights.
- Water sparingly at first, then more regularly once you see green shoots poking through the soil.
By the time the weather is warm enough to move them outside, you will already have established plants ready to take off.
Common Myths About Canna Storage
There is a lot of advice on the internet, and not all of it is helpful. Let's clear up a few common misconceptions.
Myth: You must wash them with bleach.
Some people suggest dipping rhizomes in a diluted bleach solution to kill fungi. While this can work, it is usually unnecessary and adds a chemical step that most home gardeners don't need. Good curing (air-drying) and using fresh packing materials are usually enough to prevent rot.
Myth: They need to stay completely dry.
While you don't want them sitting in water, a rhizome is a living thing. If it becomes 100% dehydrated, the cells will die. The goal is "dormant," not "mummified." This is why a packing medium like peat moss is so helpful—it maintains just a hint of ambient humidity.
Myth: You can't store them if they were damaged during digging.
Accidents happen. If you accidentally slice a rhizome with your shovel, don't throw it away! Simply let that piece cure for a few extra days so the cut can dry out completely. Many times, a damaged rhizome will heal over and grow just fine in the spring.
The Longfield Gardens Quality Promise
We want every gardener to feel successful when they plant our bulbs and rhizomes. While we cannot control the winter weather or your basement's temperature, we do stand behind the quality of the products we ship.
At Longfield Gardens, we work with the best growers to ensure you receive healthy, high-quality canna rhizomes that are true to variety.
If your items arrive damaged or you have concerns about their quality upon delivery, please contact our team promptly. We want you to have the most beautiful garden possible, and we are here to support you with practical advice every step of the way.
Key Takeaway: Successful canna storage is all about balance: keeping them cool but not freezing, and dry but not dehydrated. With a little bit of attention in the fall and a quick check-up in mid-winter, you can enjoy the same beautiful cannas for many years.
Conclusion
Canna lilies are more than just a seasonal treat; they are long-term residents of your garden that happen to take a little winter vacation indoors. By following these simple steps—waiting for the frost, curing the rhizomes, and packing them away in a cool, dark spot—you ensure that your summer garden remains a lush, tropical paradise year after year. It is a rewarding cycle that saves money and allows you to watch your favorite plants grow more impressive with every passing season.
- Wait for the first frost to blacken foliage before digging.
- Cure rhizomes for a week in a dry, protected area.
- Store in a breathable container with peat moss or wood shavings.
- Keep the storage temperature between 40°F and 50°F.
At Longfield Gardens, we are excited to help you grow a garden that brings you joy. Whether you are adding new canna varieties to your collection or carefully storing the ones you already love, we are here to provide the quality plants and simple guidance you need for a beautiful yard.
"Gardening is a journey of seasons. Learning to overwinter your favorite tropicals is one of the most satisfying skills a gardener can master, turning a one-time purchase into a lifetime of summer color."
FAQ
Can I store canna bulbs in my garage?
You can store canna bulbs in a garage only if it is well-insulated and does not drop below freezing. If your garage frequently reaches temperatures below 35°F, the bulbs will likely freeze and die. It is often safer to choose a spot against an interior wall or in a cool basement where temperatures are more stable.
Why did my canna bulbs rot during the winter?
The most common causes of rot are storing the bulbs while they are still wet, lack of air circulation, or temperatures that are too warm. Ensure your rhizomes are "cured" (air-dried) for at least a week before packing them, and make sure your storage container allows for a small amount of ventilation.
Do I have to divide my cannas every year?
No, you do not have to divide them every single year. However, cannas grow very quickly and the clumps can become quite heavy and difficult to handle after just two seasons. Dividing them every year or every other year keeps the plants healthy and gives you more bulbs to plant in other parts of your garden.
When should I take my cannas out of storage in the spring?
You can take them out of storage about a month before your last expected frost if you plan to start them in pots indoors. If you are planting them directly into the garden, wait until the soil is warm (at least 60°F) and there is no longer any danger of frost, which is usually late spring.