Table of Contents
- Introduction
- Understanding the Canna Life Cycle
- When to Begin the Overwintering Process
- Preparing the Plants for Digging
- How to Lift Canna Rhizomes Safely
- Cleaning and Inspecting Your Rhizomes
- The Importance of Curing
- Choosing the Best Storage Container and Medium
- Finding the Perfect Winter Location
- Maintaining Your Cannas During Winter
- Special Considerations for Potted Cannas
- Overwintering Cannas in Warm Climates (Zones 7 and 8)
- Bringing Cannas Out of Storage in Spring
- Encouraging Realistic Expectations
- Conclusion
- FAQ
Introduction
There is nothing quite like the bold, tropical flair of cannas to make a backyard feel like a private island getaway. Their oversized leaves and brilliant, sun-drenched flowers bring a level of energy to the garden that few other plants can match. At Longfield Gardens, we love how these easy-to-grow beauties transform a summer landscape into a lush paradise.
Because cannas are tropical plants, they thrive in the heat but are sensitive to freezing temperatures. If you live in a region with chilly winters, you can still enjoy these stunning plants year after year. Learning how to over winter canna bulbs—which are technically called rhizomes—is a simple and rewarding process that saves you money and results in even larger, more impressive displays each summer. If you love dramatic height, browse Tall Cannas.
This guide will walk you through the entire process of lifting, curing, and storing your cannas so they stay healthy until spring. Whether you are a beginner or a seasoned gardener, you will find that a little bit of fall preparation goes a long way. Protecting your garden investment is easy when you follow these clear, practical steps for winter care. For a middle-ground choice, browse Medium Cannas.
Understanding the Canna Life Cycle
To understand how to over winter canna bulbs, it helps to know how they grow. Cannas grow from rhizomes, which are thick, fleshy underground stems that store food and energy for the plant. During the long, sunny days of summer, the foliage absorbs sunlight and converts it into energy, which is then sent down into the rhizome. For a broader overview, read All About Cannas.
As autumn approaches and temperatures drop, the plant begins to transition into a dormant state. This dormancy is a natural resting period that allows the canna to survive without active growth. In warm climates, the rhizomes can stay in the ground. In colder areas, we need to provide a frost-free environment to mimic their native tropical home.
By lifting and storing these rhizomes, you are essentially hitting the "pause" button on their growth. When you bring them back out in the spring, they will be rested and ready to sprout with even more vigor. This cycle of growth and rest is what allows a single canna rhizome to multiply over time, giving you more plants to enjoy every single year.
When to Begin the Overwintering Process
Timing is everything when it comes to preparing cannas for their winter nap. You want to give the plant as much time as possible to store energy, but you must act before the ground freezes solid.
Watching for the First Frost
In most regions, the best signal to start the process is the first light frost of autumn. You will notice that the lush green or bronze leaves of your cannas will turn black or brown after a night of freezing temperatures. 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 start focusing entirely on the rhizome. While the foliage is damaged by a light frost, the rhizomes safely tucked underground are usually fine. We recommend waiting for this first frost before you begin digging, as it ensures the plant has finished its work for the season.
Monitoring Soil Temperatures
If you live in an area where frost comes very late, you can also look at soil temperatures. When the soil consistently stays below 50°F, the canna lilies will naturally begin to yellow and die back. This is another clear indicator that it is time to lift them.
The goal is to get the rhizomes out of the ground before a "hard freeze" occurs. A hard freeze is when the ground itself begins to freeze several inches deep. If the rhizomes themselves freeze, the water inside their cells expands and ruins the plant. By keeping an eye on the weather forecast in late October or November, you can find the perfect window for success.
Key Takeaway: Wait for the first light frost to blacken the leaves. This signals the plant to go dormant and ensures the rhizome has stored maximum energy for next year.
Preparing the Plants for Digging
Once the foliage has been hit by frost, the next step is to prepare the plants for removal. This makes the digging process much easier and keeps your workspace tidy.
Cutting Back the Foliage
Start by using a pair of sharp, clean garden shears or a lopper to cut the stalks back. You should leave about 2 to 4 inches of the stem remaining above the soil line. These short "handles" serve two purposes: they show you exactly where the rhizomes are located so you don't accidentally slice into them, and they provide a convenient grip when you are lifting the clumps.
Do not be afraid to cut the foliage away entirely if it is mushy or unsightly. The plant no longer needs the leaves once they have turned brown. You can add the healthy, frost-bitten leaves to your compost pile, provided they are free of pests or signs of disease.
Clearing the Area
Before you bring out the shovel, clear away any mulch, fallen leaves, or weeds from around the base of the cannas. This gives you a clear view of the soil and helps prevent you from mixing garden debris into your storage containers later. A clean workspace makes the job much more pleasant and efficient.
How to Lift Canna Rhizomes Safely
Lifting cannas is a straightforward task, but it requires a gentle touch. Since rhizomes are fleshy, they can be bruised or cut if hit directly with a sharp tool.
Using the Right Tools
A garden fork is often the best tool for this job. The tines of a fork can slide into the soil with less resistance than a solid shovel blade, reducing the risk of "chopping" a rhizome in half. If you only have a shovel, that will work too—just be sure to give the plant plenty of space.
The Lifting Technique
To lift the clump safely, follow these steps:
- Start Wide: Place your garden fork about 6 to 12 inches away from the base of the stems. Canna rhizomes can grow quite wide during the summer, and you want to avoid hitting them.
- Circle the Plant: Push the fork deep into the soil and gently pry upward. Move in a circle around the entire clump, loosening the soil from all sides.
- Leverage Upward: Once the soil is loose, use the fork to lever the entire root mass upward.
- Lift by Hand: Reach down and grab the short stem handles you left earlier. Gently lift the clump out of the hole.
If the clump is very large and heavy, do not feel like you have to lift it all at once. You can use your hands or a dull trowel to find natural breaking points in the soil and lift the clump out in smaller sections.
What to Do Next
- Shake the clump gently to remove large chunks of soil.
- Place the lifted rhizomes on a tarp or in a wheelbarrow to keep your lawn clean.
- Label each clump immediately if you are growing different varieties. For a ready-made mix, see Assorted Cannas.
Cleaning and Inspecting Your Rhizomes
Once the cannas are out of the ground, they need a little bit of grooming before they go into storage.
Removing Excess Soil
There are two schools of thought on cleaning cannas. Some gardeners prefer to let the soil dry and then gently brush it off with their hands. Others prefer to use a garden hose to wash the rhizomes clean. Both methods work well.
If you choose to wash them, use a gentle stream of water. Avoid high-pressure nozzles that could tear the delicate outer skin of the rhizome. Washing the rhizomes makes it much easier to see their condition and check for any hidden pests. However, if you wash them, you must be extra diligent about the "curing" phase to ensure they are completely dry before storage.
Inspecting for Health
Take a moment to look closely at your harvest. A healthy canna rhizome should feel firm, similar to a fresh potato. If you find any parts that feel soft, mushy, or hollow, these should be trimmed away.
If a rhizome has been accidentally cut by your shovel, don't worry. Simply trim the jagged edge so it is a clean cut. You can dust the cut ends with a little bit of sulfur powder (available at most garden centers) to help prevent rot, though this is often not necessary if the rhizome is allowed to dry properly.
To Divide or Not to Divide?
Many gardeners wonder if they should divide their cannas in the fall or wait until spring. While you can do it now, we generally recommend waiting until spring. Keeping the clumps larger over the winter helps prevent the individual rhizomes from drying out too quickly. In the spring, you will also be able to see the "eyes" (growing points) more clearly, making it easier to decide where to make your cuts.
The Importance of Curing
Curing is perhaps the most important step in the overwintering process. Curing is simply the process of allowing the rhizomes to air-dry in a protected area for several days.
Why Curing Matters
When you first dig up a canna, its skin is thin and full of moisture. If you put it directly into a storage box, that moisture can lead to mold and rot. Curing allows the outer "skin" of the rhizome to toughen up and creates a protective barrier. It also ensures that any surface moisture from washing has evaporated.
How to Cure Properly
Find a dry, well-ventilated spot that is protected from rain and direct frost. A garage, a garden shed, or a covered porch works beautifully. Spread the rhizomes out in a single layer on a piece of cardboard, newspaper, or a mesh screen.
Leave them there for about 3 to 7 days. The exact timing depends on your humidity and temperature. You will know they are cured when the outside feels dry to the touch and any remaining soil has turned into a fine, dry powder.
Key Takeaway: Give your rhizomes a few days to air-dry in a protected spot. This toughens the skin and is your best defense against winter rot.
Choosing the Best Storage Container and Medium
Now that your cannas are clean and cured, it is time to pack them away for the season. The goal is to keep them dormant, cool, and just slightly moist so they don't shrivel up.
Selecting a Container
You want a container that allows for a small amount of airflow while keeping the storage medium contained. Great options include:
- Cardboard boxes
- Paper grocery bags
- Plastic bins with the lids left cracked open or holes drilled in the sides
- Wooden crates or nursery flats
Avoid sealing them in airtight plastic bags or containers with tight lids. Without airflow, any remaining moisture will cause the rhizomes to rot very quickly.
Choosing a Storage Medium
Filling the container with a "packing material" helps regulate moisture and insulates the rhizomes. Some of our favorite materials include:
- Peat Moss: This is a classic choice because it holds just the right amount of moisture and is naturally slightly acidic, which can help discourage fungal growth.
- Vermiculite or Perlite: These lightweight minerals are excellent for maintaining a consistent environment.
- Wood Shavings: Common "pet bedding" found at supply stores works well and is very affordable.
- Newspaper: You can simply wrap each rhizome in a few layers of dry newspaper.
How to Pack Them
Start by placing a 2-inch layer of your chosen medium at the bottom of the container. Lay the rhizomes on top, making sure they aren't crowded or touching each other too much. If you have a lot of cannas, you can create multiple layers, separated by more packing material.
The goal is to have the rhizomes "nestled" in the material so they are protected from the air but not suffocating.
Finding the Perfect Winter Location
Where you store your boxes is just as important as how you pack them. Cannas need a spot that stays consistently cool but never reaches freezing.
The Ideal Temperature Range
The "Goldilocks" temperature for canna storage is between 40°F and 50°F.
- If it's too warm: The plants may try to start growing prematurely in the dark, which exhausts their energy.
- If it's too cold: They could freeze and die.
Common Storage Spots
- Unheated Basements: Usually the most reliable spot for consistent temperatures.
- Attached Garages: Often work well, but be careful if the temperature in your garage drops significantly during a cold snap. Place the boxes on a shelf or a wooden pallet rather than directly on the cold concrete floor.
- Crawl Spaces: These stay naturally cool and humid, which cannas love.
- Root Cellars: The traditional choice for many "bulb" plants.
Maintaining Your Cannas During Winter
Overwintering isn't a "set it and forget it" task. To ensure a high survival rate, you should check on your cannas about once a month.
The "Squeeze Test"
During your monthly check, pick up a few rhizomes and give them a gentle squeeze.
- If they feel firm: They are doing great! Put them back and check again next month.
- If they feel soft or mushy: This is a sign of rot. Use a clean knife to cut away the affected area and leave the rhizome out to dry for a day before putting it back in fresh, dry packing material.
- If they feel very light and shriveled: They are getting too dry.
Adjusting Moisture Levels
If your rhizomes look shriveled like a prune, they are losing too much moisture. You can fix this easily. Use a spray bottle to lightly mist the packing material (not the rhizome itself) with a little bit of water. You don't want the material to be wet or soggy—just slightly damp to the touch. This small amount of humidity will help the rhizome plump back up.
What to Do Next
- Mark your calendar for a "check-in" date once every four weeks.
- Remove any rhizomes that show significant rot to prevent it from spreading to the healthy ones.
- Ensure the storage area hasn't become too damp from winter rains or snowmelt.
Special Considerations for Potted Cannas
If you grow your cannas in large decorative containers, you have an even easier path to overwintering. If you want a compact container display, Short Cannas are a natural fit.
Once the first frost hits, cut the foliage back to the soil level as you would with garden plants. Move the entire pot into a cool, frost-free area like a basement or garage. Stop watering them entirely. The soil in the pot will act as the storage medium. For more container-growing ideas, see How to Grow Summer Bulbs in Containers.
If the pot is too heavy to move, you will need to follow the standard digging and lifting instructions described above.
Overwintering Cannas in Warm Climates (Zones 7 and 8)
If you live in USDA Hardiness Zones 8 through 10, cannas are generally considered hardy and can stay in the ground all year. In Zone 7, it's a bit of a gamble depending on the severity of the winter. To check your zone, use the Hardiness Zone Map.
Mulching for Protection
If you decide to leave your cannas in the ground in these warmer zones, you should still give them some protection. After the foliage dies back, cut it to the ground and apply a thick layer of mulch. Six to eight inches of straw, shredded leaves, or wood chips will act as a blanket, keeping the soil temperature more stable.
Microclimates Matter
Cannas planted near the foundation of a house or on the south side of a stone wall often benefit from "thermal mass." These areas stay slightly warmer than the rest of the garden. If your cannas are in a protected spot like this, they are much more likely to survive a colder-than-average winter in the ground.
Bringing Cannas Out of Storage in Spring
The most exciting part of the process is seeing those first signs of life in the spring! When the danger of frost has passed and the soil has warmed up to at least 60°F, you can begin the replanting process. For step-by-step planting details, see How to Plant Canna Lily Bulbs in the Ground.
Waking Them Up
A few weeks before your last frost date, you can move your storage boxes to a slightly warmer, brighter spot. This gently signals to the rhizomes that it is time to wake up. You may even see small white or pink "eyes" beginning to sprout.
Dividing for More Plants
Spring is the perfect time to divide your cannas. Use a clean, sharp knife to cut the rhizomes into smaller pieces. Each piece should have at least one or two healthy-looking "eyes." Allow the cut ends to dry for a few hours before planting to prevent soil-borne diseases from entering the fresh cuts.
Planting Depth and Care
Plant your canna rhizomes about 4 to 6 inches deep with the eyes pointing upward. Space them about 1 to 2 feet apart, depending on the variety. Give them a good drink of water to settle the soil, and then wait for the magic to happen. Before you know it, you will have those spectacular tropical leaves reaching for the sun once again.
Encouraging Realistic Expectations
While we aim for a 100% survival rate, it is normal to lose a few rhizomes over the winter. Nature is unpredictable, and factors like storage humidity and the health of the plant during the summer play a role. If 80% of your cannas make it through the winter, you should consider your efforts a resounding success!
Remember that gardening is a journey of observation. Each winter you store your bulbs, you will learn more about the specific microclimate of your home and storage areas. Over time, you will develop a "gut feeling" for exactly how much moisture or airflow your plants need.
Key Takeaway: Spring is the reward for your fall efforts. Dividing your healthy rhizomes in the spring is like getting free plants for your garden!
Conclusion
Mastering the art of how to over winter canna bulbs is one of the most satisfying skills a gardener can learn. It turns a one-season plant into a lifelong garden companion. By following the simple steps of waiting for the frost, curing the rhizomes, and providing a cool, dark winter home, you ensure that your garden will always have that touch of tropical brilliance. At Longfield Gardens, we stand behind every order with our 100% Quality Guarantee.
At Longfield Gardens, we want every gardener to feel confident in their ability to grow and maintain a beautiful landscape. Saving your cannas is not just about being practical; it is about the joy of seeing a familiar plant return each year, bigger and more beautiful than before. If you like to browse by style and palette, see Shop by Color - Spring-Planted Bulbs.
- Timing: Wait for the first frost to signal dormancy.
- Curing: Give rhizomes a few days to dry before packing.
- Storage: Keep them cool (40-50°F) in a breathable container with peat moss or wood shavings.
- Maintenance: Check monthly for rot or extreme dryness.
We are here to help you grow your best garden yet. With a little bit of care this autumn, you’ll be ready to enjoy a stunning, tropical-inspired landscape when the warm weather returns!
FAQ
Can I store canna bulbs in a refrigerator?
It is usually not recommended to store canna rhizomes in a standard refrigerator. Kitchen refrigerators are often too cold (below 40°F) and the air is very dry, which can cause the rhizomes to shrivel or die. Additionally, some fruits release ethylene gas that can interfere with the health of the dormant plants.
Do I have to wash the soil off the cannas before storing?
No, washing is not strictly necessary. Many gardeners find it easier to let the soil dry and then gently brush off the excess. If your soil is heavy clay, washing can help you see the condition of the rhizome more clearly, but if you have sandy soil, a simple shake is often enough.
What happens if I forget to dig them up before a hard freeze?
If the ground freezes solid before you dig your cannas, the rhizomes may be damaged. However, if the freeze was brief, the soil may have insulated them. Dig them up as soon as possible and check the rhizomes—if they are still firm and not mushy, they may have survived and are worth trying to save.
Should I fertilize my cannas before they go into storage?
No, you should stop fertilizing cannas in late summer, usually by August. Providing fertilizer late in the season encourages new, tender growth that won't have time to mature before the frost. You want the plant to naturally slow down and prepare for dormancy rather than pushing out new leaves.