Introduction
There is nothing quite like the tropical flair canna lilies bring to a summer garden. Their bold, architectural foliage and vibrant blooms in shades of red, orange, yellow, and pink create a vacation-like atmosphere right in your backyard. At Longfield Gardens, we want to help you keep that beauty returning year after year. While these plants are famous for their heat-loving nature, they are not naturally hardy in colder climates.
Learning how to save canna lily bulbs—which are technically called rhizomes—is a simple and rewarding process. Instead of treating these spectacular plants as annuals, you can easily lift and store them for the winter. This practice not only saves money but also allows you to grow your collection as the rhizomes naturally multiply. We will walk you through the timing, the best lifting techniques, and the ideal storage conditions to ensure your cannas arrive in spring ready to grow.
Saving your cannas is a straightforward task that preserves your favorite varieties and ensures a bigger, better display next season.
Understanding the Canna Lily Rhizome
Before you start digging, it helps to understand what you are working with. While most gardeners refer to them as "bulbs," cannas actually grow from rhizomes. A rhizome is a fleshy, horizontal underground stem that stores energy for the plant. If you look closely at a canna rhizome, you will see small bumps or "eyes." These are the growth points where next year's stems and leaves will emerge.
The primary goal of saving canna bulbs is to keep these rhizomes healthy and dormant through the winter. In their native tropical environments, cannas grow year-round. In most parts of the United States, however, the freezing temperatures of winter would turn the water-filled rhizomes into mush. By lifting them out of the soil and bringing them into a frost-free environment, we mimic their natural dormancy and protect their energy stores.
Success with cannas starts with identifying your garden's hardiness zone. In USDA zones 8 to 10, cannas are generally hardy and can stay in the ground year-round with a thick layer of mulch for protection. For gardeners in zone 7 and colder, lifting is necessary. Even in warmer zones, many gardeners choose to lift their cannas every few years to divide the clumps and refresh the soil.
The Importance of Timing
Timing is everything when it comes to saving canna lily bulbs. You want to give the plant as much time as possible to store energy in the rhizome, but you must act before the ground freezes solid. The ideal window for lifting cannas usually opens in late autumn.
The best signal that it is time to dig comes from nature itself. Most gardeners wait for the first light frost to hit the foliage. This frost will turn the leaves brown or black, signaling to the plant that the growing season is over. This "cold shock" tells the canna to send all its remaining nutrients down into the rhizomes for winter storage.
If you live in an area where frost comes very late, you can simply wait until the foliage begins to yellow and die back naturally as the days shorten. As long as you dig them up before a deep, hard freeze penetrates the soil, your rhizomes will be safe. A light surface frost will not damage the buried rhizomes, but it is a clear reminder to get your garden fork ready.
Key Takeaway: Wait for the first frost to blacken the leaves before digging. This ensures the rhizomes have stored the maximum amount of energy for next year’s blooms.
Preparing to Lift Your Cannas
Lifting cannas is a simple physical task, but doing it correctly prevents damage that could lead to rot during storage. You do not need specialized equipment; a few basic garden tools are all it takes to get the job done.
Tools You Will Need
- A garden fork or spade: A garden fork is often preferred because it is less likely to slice through the rhizomes than a flat shovel.
- Pruning shears or loppers: You will need these to cut back the heavy stalks.
- Garden gloves: Canna stalks can be thick and messy to handle.
- Tags and markers: If you grow different varieties, it is vital to label them now before the flowers are gone.
Cutting Back the Foliage
Before you start digging, clear the way by cutting back the foliage. Use your shears to cut the stalks down to about 2 to 4 inches above the soil line. Leaving a short "handle" of stalk makes it easier to grab the clump and helps you keep track of where the rhizomes are located while you work.
Digging with Care
Cannas can grow significantly over a single season. A small rhizome planted in May can turn into a heavy, sprawling clump by October. To avoid damaging the fleshy roots, start digging about 6 to 12 inches away from the base of the stalks.
Insert your garden fork deeply into the soil and gently pry upward. Work your way around the entire clump in a circle, loosening the soil as you go. Once the soil is loose, you can lift the entire mass of rhizomes out of the ground. Don't be surprised if the clump is much larger and heavier than you expected—this is a sign of a healthy, happy plant!
Initial Cleaning
Once the clump is out of the ground, gently shake off the loose soil. You can use your hands to brush away larger clods of dirt. It is usually best to avoid using a high-pressure hose to spray them clean at this stage, as excess moisture can encourage rot. If the soil is very sticky or clay-heavy, a light rinse is fine, but you must be extra diligent about the drying process that follows.
What to do next:
- Label your plants by color or variety name using garden tape or tags.
- Cut stalks down to 4 inches.
- Lift the clumps using a wide circle to prevent "forking" the rhizomes.
- Remove large clumps of soil by hand.
The Curing Process
Curing is perhaps the most overlooked step in saving canna lily bulbs, but it is one of the most important. Curing is the process of allowing the rhizomes to air-dry for a short period before they are packed away for winter. This helps the "skin" of the rhizome toughen up, making it more resistant to fungal issues and rot.
To cure your cannas, find a dry, well-ventilated spot that is protected from frost and direct rain. A garage, a garden shed, or a covered porch works perfectly. Lay the rhizomes out in a single layer on a piece of cardboard, newspaper, or a mesh screen.
The curing process typically takes about 4 to 7 days. You want the exterior of the rhizome to feel dry to the touch and any remaining soil to turn into a dry powder. During this time, the cut ends of the stalks will also begin to dry and seal over. This natural seal acts as a barrier against disease during the long winter months.
Dividing Canna Rhizomes
One of the best things about saving cannas is that they provide you with free plants. Over the summer, the rhizomes grow and branch out. You can choose to divide them in the fall after they have been cleaned, or you can wait until the spring.
Many gardeners prefer to wait until spring to divide, as the "eyes" or growth points are easier to see once the plant begins to wake up. However, if your clumps are too large to store comfortably, fall division is a great option.
To divide a clump, look for natural points where the rhizomes can be separated. You can often pull them apart by hand, or you can use a sharp, clean knife. Each division should have at least one to three healthy-looking eyes. If you use a knife, let the cut pieces dry for an extra day to allow the wound to callus over before packing them away.
Choosing the Right Storage Medium
The goal of storage is to keep the rhizomes dormant, cool, and just slightly moist. If they are too wet, they will rot; if they are bone-dry, they will shrivel up and die. Finding the right balance is easy when you use the right storage medium.
Peat Moss or Vermiculite
These are the most popular choices for storing cannas. Both materials are excellent at regulating moisture. We recommend using slightly dampened peat moss—it should feel like a wrung-out sponge, not dripping wet. Place a layer of the medium in the bottom of a box, add your rhizomes, and then cover them completely.
Wood Shavings
Pine or cedar shavings (the kind sold for animal bedding) are another great option. They provide excellent insulation and allow for a small amount of airflow, which helps prevent stagnant air from causing mold.
Newspaper
For a simple and low-cost method, you can wrap individual rhizomes in several layers of newspaper. Place the wrapped bundles in a cardboard box. The newspaper helps absorb excess moisture while providing a buffer against temperature changes.
Plastic Bags vs. Cardboard Boxes
While some gardeners use plastic bags with air holes punched in them, we generally recommend cardboard boxes or plastic bins with the lids left slightly ajar. Cardboard is breathable, which is a major advantage in preventing the "sweating" that leads to rot. If you use a plastic bin, make sure it is not airtight.
Key Takeaway: The storage medium acts as a blanket for your rhizomes. It should keep them from drying out completely without trapping too much moisture.
The Ideal Storage Environment
Once your canna bulbs are packed, they need a "winter home." The location you choose will determine how well they survive until spring.
Cannas need a cool, dark place. The ideal temperature range is between 40°F and 55°F. If the temperature stays in this range, the rhizomes will remain dormant. If it gets too warm, they may try to start growing in the dark, using up their stored energy. If it drops below freezing, the cells inside the rhizome will rupture, and the plant will not survive.
Ideal storage locations include:
- An unheated (but frost-free) basement.
- A crawl space.
- An attached garage that stays above freezing.
- A cool closet or pantry in a colder part of the house.
Avoid storing your cannas near a furnace, water heater, or any other heat source. Also, keep them away from fresh fruit, such as apples, which release ethylene gas that can interfere with the dormancy of the bulbs.
Overwintering Cannas in Containers
If you grow your cannas in large pots or containers, you have a shortcut available to you. You do not necessarily have to dig the rhizomes out of the soil. Instead, you can overwinter the entire container.
After the first frost, cut the foliage back to the soil line as you would with garden-grown plants. Move the entire pot into a cool, frost-free location like a basement or garage. Stop watering the pot entirely. The soil will dry out, and the cannas will go dormant.
In the spring, you can bring the pot back out into the sun, give it a fresh layer of compost, and start watering again. Every two to three years, you should still remove the plants from the pot to divide them and refresh the soil, as cannas can quickly become "root-bound" in containers.
Winter Maintenance Checks
Saving canna bulbs isn't a "set it and forget it" task. To ensure the highest survival rate, it is a good idea to check on your stored rhizomes about once a month. This takes only a few minutes but can save your entire collection if an issue arises.
Open your storage boxes and take a quick look.
- Check for rot: If you see any rhizomes that look mushy, slimy, or have a foul odor, remove them immediately. This prevents the rot from spreading to the healthy ones.
- Check for shriveling: If the rhizomes look very wrinkled or feel lightweight, they may be drying out too much. Use a spray bottle to lightly mist the storage medium with water. You don't want it wet, just slightly humid.
- Check for growth: If you see white sprouts beginning to grow, your storage area might be too warm. Try to find a slightly cooler spot for the remainder of the winter.
What to do next:
- Set a monthly reminder on your calendar to check your bulbs.
- Discard any soft or moldy rhizomes right away.
- Lightly mist the medium if it feels bone-dry.
Preparing for Spring Planting
As the days grow longer and the ground begins to warm, it is time to think about bringing your cannas out of storage. In most regions, cannas can be planted outdoors once the danger of frost has passed and the soil temperature has reached at least 60°F.
Waking Them Up Early
If you want to get a head start on the season, you can "start" your cannas indoors about 4 to 6 weeks before the last frost date. Plant the rhizomes in pots with potting soil and place them in a warm, sunny window or under grow lights. This gives the plants a few inches of growth before they ever hit the garden, resulting in much earlier blooms.
Dividing for Success
If you didn't divide your clumps in the fall, now is the time. Look for the "eyes" and cut the rhizomes into sections. Each piece should have at least one healthy eye. Let the cuts dry for a few hours before planting to prevent soil-borne diseases from entering the fresh wounds.
Planting Depth and Spacing
When you are ready to plant outdoors, choose a spot with full sun—at least 6 to 8 hours of direct sunlight a day. Cannas are heavy feeders, so mixing some compost or well-rotted manure into the soil will give them the nutrients they need to produce those massive leaves and bright flowers.
Plant the rhizomes about 4 to 5 inches deep. For spacing, give dwarf varieties about 1 foot of room, while taller varieties need 2 feet or more to accommodate their wide foliage. Water them in well, and soon you will see the first pointed leaves poking through the soil.
Why Saving Your Own Bulbs Is Worth It
Beyond the cost savings, there is a deep sense of satisfaction in successfully overwintering your own plants. When you save your canna rhizomes, you are participating in the full cycle of the garden. You get to see how the plants grow and change over the years.
Many gardeners find that the cannas they save themselves perform even better than store-bought ones. Because the rhizomes are already "acclimated" to your local environment and have grown large over the previous season, they often emerge with more vigor and produce more flowers.
At Longfield Gardens, we believe that gardening should be a rewarding and accessible hobby for everyone. By following these simple steps to save your canna lily bulbs, you ensure that your garden remains a vibrant, tropical oasis year after year without starting from scratch every spring.
Troubleshooting Common Storage Issues
While the process is generally very successful, you may occasionally run into a few challenges. Staying positive and making small adjustments is the best way to handle these situations.
The rhizomes are soft and mushy. This is usually caused by too much moisture in the storage medium or a lack of airflow. If only a small part is soft, you can sometimes cut the mushy part away with a clean knife, let it dry, and repattern your storage with a drier medium. If the whole rhizome is soft, it’s best to discard it.
The rhizomes are very shriveled. This happens when the storage area is too dry or the medium (like dry peat moss) has pulled the moisture out of the plant. A light misting once a month is usually enough to prevent this. Even if they look a bit wrinkled, many will still grow if you soak them in lukewarm water for an hour before planting in the spring.
The stalks are starting to sprout in February. Your storage area is likely a bit too warm. Move the boxes to the coolest part of the basement or garage (as long as it stays above freezing). If they have already grown several inches, you might need to pot them up and treat them as houseplants until it is warm enough to go outside.
"Saving canna bulbs is a bridge between gardening seasons. It turns a summer favorite into a perennial tradition that grows along with your skill as a gardener."
Conclusion
Saving canna lily bulbs is one of the easiest ways to ensure your garden stays lush and colorful without needing to buy new plants every year. By waiting for the first frost, curing the rhizomes properly, and storing them in a cool, dark place, you protect the energy they worked so hard to store all summer. We invite you to try this process with your own cannas this autumn.
Remember these key steps:
- Dig after the first light frost has signaled dormancy.
- Cure the rhizomes for a week in a dry, airy spot.
- Store in a breathable medium like peat moss or newspaper.
- Keep them in a cool, frost-free location (40-55°F).
At Longfield Gardens, we take pride in providing high-quality bulbs and the knowledge you need to make them thrive. Whether you are a beginner or a seasoned pro, overwintering your cannas is a rewarding task that pays off in spectacular blooms next summer. For your next garden project, consider trying a new canna variety to add even more color to your collection.
FAQ
Can I leave canna lilies in the ground during winter?
Whether you can leave cannas in the ground depends on your USDA hardiness zone. If you live in zones 8 to 10, cannas are usually hardy and can stay in the soil, especially if you apply a thick layer of mulch. In zone 7, they may survive mild winters in protected spots, but in zones 6 and colder, the ground freezes deep enough to kill the rhizomes, making lifting necessary.
Do I need to wash the dirt off the canna bulbs before storing?
It is generally better to shake off the loose soil rather than washing them with a hose. Excess water can get trapped in the nooks and crannies of the rhizomes, increasing the risk of rot during winter storage. If the soil is very muddy, you can rinse them lightly, but ensure they have plenty of time to dry completely during the curing phase before you pack them away.
What should I do if my stored canna bulbs start to grow early?
If you see sprouts before spring arrives, it usually means your storage area is too warm. Try moving the bulbs to a cooler location that stays above freezing, such as a different part of the basement or an attached garage. If the sprouts are already several inches long, you can plant the rhizomes in pots and grow them indoors near a sunny window until the outdoor weather is warm enough for planting.
Why did my stored canna rhizomes turn into mush?
Mushy rhizomes are a sign of rot, which is usually caused by one of three things: storing them while they were still too wet, a lack of airflow in the storage container, or the rhizomes freezing during the winter. To prevent this, ensure they are well-cured (dried) for about a week before storage and keep them in a location that stays consistently between 40°F and 55°F.
