Simple Ways to Dig and Store Canna Bulbs

Table of Contents

1. Introduction
2. Understanding the Canna Lifecycle
3. When to Start the Process
4. Checking Your Hardiness Zone
5. Preparing the Plants for Digging
6. How to Dig Canna Rhizomes
7. Cleaning and Curing the Rhizomes
8. Should You Divide the Clumps?
9. Selecting the Right Storage Container
10. Using a Storage Medium
11. Finding the Ideal Storage Location
12. Winter Maintenance and Monitoring
13. Transitioning to Spring
14. Realistic Expectations for Success
15. Summary of the Process
16. FAQ

Introduction

Canna lilies bring a bold, tropical flair to any garden with their oversized leaves and vibrant, orchid-like flowers. Watching these statuesque plants reach their full height in midsummer is one of the most rewarding experiences a gardener can have. Whether you grow them for their sunset-colored blooms or their dramatic variegated foliage, cannas are high-impact plants that make every summer feel like a vacation.

As the season winds down, many gardeners want to ensure these beautiful plants return year after year. At Longfield Gardens, we want to help you preserve your investment so you can enjoy these tropical favorites for many seasons to come. While cannas are tender perennials, storing them for the winter is a straightforward process that any gardener can master with just a little bit of time and a cool corner in the house.

This guide will walk you through the best practices to dig, clean, and store canna bulbs so they stay healthy until spring. By following a few simple steps, you can successfully overwinter your rhizomes and get a head start on next year's garden. With the right approach, storing your cannas becomes a satisfying end-of-season ritual.

Understanding the Canna Lifecycle

Before you grab your shovel, it helps to understand what a canna actually is. While we often call them "bulbs," cannas grow from thick, fleshy underground stems known as rhizomes. These rhizomes act as a storage tank for the plant, holding onto energy and nutrients throughout the growing season to fuel the next year’s growth.

In warm climates, cannas can stay in the ground all year. In most parts of the United States, however, the winter temperatures drop low enough to freeze the ground. Because canna rhizomes are full of moisture, they cannot survive a deep freeze. If the water inside the rhizome freezes, it damages the plant tissue, which usually leads to rot once the soil warms up again.

Storing canna bulbs is simply a way of protecting that stored energy from the cold. When you dig them up, you are helping the plant enter a period of dormancy. This rest period is essential for the plant's health. Once the days get shorter and the temperatures drop, the plant naturally begins to slow down, preparing to wait out the winter indoors.

When to Start the Process

Timing is one of the most important factors when you want to store canna bulbs. You want to give the plant as much time as possible to store energy, but you must get them out of the ground before the soil freezes solid.

The best signal to start digging is the first "killing frost." This is the frost that turns the lush green or bronze foliage to a dark, wilted brown. While it might look a bit sad to see your beautiful plants wilt, this is actually a helpful sign from nature. The frost tells the plant that it is time to go dormant.

Once the foliage has been hit by frost, the nutrients from the leaves move down into the rhizome. This final boost of energy helps the plant survive its winter slumber. We recommend waiting a few days after the first frost before you begin digging. If you live in an area where frost comes very late, you can simply wait until the leaves begin to yellow and die back naturally in late autumn.

Key Takeaway: Wait for the first frost to turn the foliage brown. This signals the plant to move its energy into the rhizome for winter storage.

Checking Your Hardiness Zone

Knowing your USDA plant hardiness zone will help you decide if you even need to dig up your cannas. These zones are based on the average annual minimum winter temperature in your area.

• Zones 8 to 11: In these warmer regions, cannas are usually hardy enough to stay in the ground. You can simply cut the foliage back to the ground after it yellows and cover the area with a few inches of mulch for protection.
• Zone 7: This is a "swing" zone. In many years, a thick layer of mulch (about 6 inches of straw or leaves) is enough to keep the rhizomes safe. However, during an unusually cold winter, they might not survive. Many gardeners in Zone 7 choose to dig them up just to be safe.
• Zones 3 to 6: In these cooler climates, the ground will freeze deep enough to kill the rhizomes. To keep your plants alive, you must dig and store them indoors.

If you are unsure of your zone, it is always better to be safe and dig them up. It is a great way to ensure your favorite varieties, like the ones we offer at Longfield Gardens, are ready to sprout again in the spring.

Preparing the Plants for Digging

Once the frost has arrived and you are ready to work, the first step is to manage the foliage. Dealing with five-foot-tall stalks while trying to dig can be clumsy and difficult.

Use a sharp pair of garden shears or a lopper to cut the stalks down. You should leave about 2 to 4 inches of stem protruding from the ground. This remaining bit of stalk serves as a convenient "handle" when you are lifting the rhizomes out of the dirt. It also helps you identify which end of the clump is the top when it comes time to replant in the spring.

After cutting back the foliage, clear away any mulch or debris from the base of the plant. This gives you a clear view of the soil surface so you can see exactly where the clump begins and ends. Cannas can spread significantly during a single summer, so the clump might be much larger than the one you originally planted.

How to Dig Canna Rhizomes

To store canna bulbs successfully, you must keep the rhizomes intact and avoid wounding the fleshy tissue. Scratches and cuts can create openings for fungi or bacteria during the storage months.

1. Choose the right tool: A garden fork is often better than a shovel. The tines of a fork are less likely to slice through a rhizome than a solid spade blade.
2. Give them space: Start digging about 10 to 12 inches away from the base of the stems. If you dig too close, you will likely chop off the growing tips of the rhizomes.
3. Loosen the soil: Insert your fork deep into the ground and gently pry upward. Work your way all the way around the plant, loosening the soil in a wide circle.
4. Lift the clump: Once the soil is loose, use your tool to gently lift the entire root mass out of the ground.
5. Shake off the excess: Pick up the clump by the remaining stems and gently shake it to remove large chunks of soil. Do not bang the rhizomes against a hard surface, as this can bruise them.

What to Do Next: Post-Digging Steps

• Cut the stems down to 3 inches.
• Dig a wide circle around the plant to avoid damage.
• Gently lift the clump rather than pulling by the stems.
• Shake off loose dirt but don't worry about getting them perfectly clean yet.

Cleaning and Curing the Rhizomes

After lifting the cannas, they need a little bit of grooming before they go into storage. Some gardeners prefer to wash their rhizomes with a hose, while others prefer to let the dirt dry and then brush it off. Both methods work, but if you wash them, you must be very diligent about the drying process.

If you choose to rinse them, use a gentle stream of water to remove the soil from the crevices. This allows you to inspect the rhizomes for any signs of pests or soft spots. If you notice any mushy or damaged areas, use a clean knife to trim them away until you reach healthy, white tissue.

Curing is perhaps the most important part of the process. Curing allows the "skin" of the rhizome to toughen up, which helps prevent rot and keeps the moisture inside the plant during the winter.

Place your cleaned rhizomes in a well-ventilated, frost-free area. A garage, shed, or covered porch works well, provided the temperatures stay above freezing. Spread them out in a single layer on a piece of cardboard or a mesh screen. Let them dry for 2 to 7 days. You will know they are ready when the exterior feels dry to the touch and any remaining soil has turned to dust.

Should You Divide the Clumps?

During the growing season, a single canna rhizome can multiply into a large, heavy mass. You can choose to store the entire clump as it is, or you can divide it into smaller pieces now.

Dividing before storage can save space in your storage bins. It also gives you more plants to share with friends or to place in different areas of your garden next year. To divide them, look for the "eyes"—these are the small, pointed bumps where the new stems will grow.

Use a clean, sharp knife to cut the rhizome into sections. Each section should have at least two or three healthy eyes. If you divide them now, make sure the cut ends have a day or two to dry and "callous" over before you pack them away. This callous acts as a protective barrier against disease.

Selecting the Right Storage Container

The goal of storage is to keep the rhizomes dormant, cool, and slightly moist. If they get too wet, they will rot. If they get too dry, they will shrivel up and may not have enough energy to sprout in the spring.

There are several ways to house your cannas for the winter:

• Cardboard Boxes: These are breathable and easy to find. They allow for some air exchange, which is good for preventing mold.
• Plastic Bins: If you use plastic totes, do not put the lid on tightly. Leave the lid slightly ajar or drill several small holes in the sides to allow for ventilation.
• Paper Bags: Large grocery bags are excellent for smaller quantities. You can tuck a few rhizomes into each bag and fold the top over.
• Nursery Pots: Some gardeners like to store their rhizomes in the same pots they used during the summer. You can simply cut the foliage back and move the entire pot into a cool basement.

Using a Storage Medium

While you can store canna bulbs "naked" in a box, they usually fare much better if they are nestled in a packing material. This material helps regulate moisture levels, preventing the rhizomes from drying out too quickly.

Peat Moss and Vermiculite: These are the most common choices. They are lightweight and hold just enough moisture to keep the rhizomes plump. Wood Shavings: Pine or cedar shavings (the kind used for animal bedding) are excellent. They allow for great airflow and have natural antifungal properties. Newspaper: You can wrap each individual rhizome in several layers of dry newspaper. This is a simple, low-cost method that works surprisingly well for many gardeners.

When packing, place a layer of your chosen material at the bottom of the container. Add a layer of rhizomes so they aren't touching each other, then cover them with more material. Repeat this until the container is full.

Key Takeaway: Use a breathable storage medium like peat moss or wood shavings to keep rhizomes from drying out or rotting.

Finding the Ideal Storage Location

Where you put your storage bins is just as important as how you pack them. Cannas need a spot that is dark, dry, and consistently cool but never freezing.

The ideal temperature range is between 40°F and 55°F.

• Unheated Basements: These are often the perfect environment. They stay cool and usually have just enough humidity.
• Crawl Spaces: These can work well, provided they are easy to access for occasional checkups.
• Cool Closets: If you live in an apartment or a house without a basement, an interior closet far away from heating vents can work.

Avoid storing your cannas in an attached garage or an attic. These spaces often experience extreme temperature swings. A sudden cold snap could freeze the rhizomes, or a warm sunny day could heat the space up enough to trick the plants into thinking it is springtime, causing them to sprout prematurely.

Winter Maintenance and Monitoring

Storing canna bulbs is not a "set it and forget it" task. You should check on your rhizomes about once a month throughout the winter. This only takes a few minutes but can save your entire collection from a single bad apple.

When you open your bins, look for the following:

1. Signs of Rot: If a rhizome feels mushy or smells bad, remove it immediately. Rot can spread quickly from one plant to another.
2. Shriveling: If the rhizomes look very wrinkled and feel light, they are losing too much moisture. Give the storage medium a light misting with a spray bottle. You don't want it wet—just slightly damp, like a wrung-out sponge.
3. Early Sprouting: If you see pale green shoots beginning to grow, your storage area might be too warm. Try to move the bin to a cooler spot to keep the plants dormant until spring.

By keeping an eye on them, you can adjust the conditions as needed. Most of the time, they will sit quietly through the winter, waiting for the warmth of May to return.

Transitioning to Spring

As the weather begins to warm up in the spring, you will notice your stored cannas starting to wake up. This usually happens around the time of your last local frost.

You can give your cannas a head start by "waking them up" indoors about 4 to 6 weeks before the last frost date. Take them out of their storage bins and place them in pots with some moist potting soil. Put the pots in a warm, sunny window. By the time the soil outside is warm enough for planting, you will already have established plants ready to go into the ground.

If you prefer to plant directly into the garden, wait until the soil temperature reaches at least 60°F. Cannas love heat, and they won't do much if the soil is still cold and damp from winter rains.

Realistic Expectations for Success

While storing canna bulbs is highly successful for most gardeners, it is important to remember that these are living things. Factors like the humidity in your home, the age of the rhizomes, and the weather during the previous growing season all play a role in how well they overwinter.

Don't be discouraged if you lose a few rhizomes to rot or shriveling over the winter. This is a normal part of gardening. Even professional growers expect a small percentage of loss during dormancy. The beauty of cannas is that they multiply so quickly during the summer that you will usually have more than enough healthy rhizomes to fill your garden again.

Focus on the basics: dig after the frost, dry them well, and keep them cool. These simple steps are the foundation of successful overwintering and will give you the best chance for a stunning tropical display next year.

Summary of the Process

Taking care of your cannas in the winter is an easy way to build a bigger, better garden every year. Instead of buying new plants every spring, you can watch your own collection grow in size and beauty.

• Wait for the signal: Let the first frost tell you when it is time to dig.
• Handle with care: Use a garden fork and dig wide to keep the rhizomes safe.
• Dry thoroughly: Curing for a few days prevents rot in storage.
• Pack it up: Use breathable containers and a medium like peat moss or shavings.
• Stay cool: Find a dark spot between 40°F and 55°F.
• Check in: Give your bins a quick monthly inspection.

At Longfield Gardens, we believe that gardening should be a rewarding and enjoyable journey. Saving your canna bulbs is a great way to stay connected to your garden even when the ground is covered in snow. When those first sprouts appear in the spring, you'll be glad you took the time to keep them safe through the winter.

We are here to help you succeed. Whether you are planting your very first canna or managing a large collection, following these simple steps will ensure your garden remains a vibrant, tropical oasis year after year.

FAQ

Can I store canna bulbs in a refrigerator?

Storing canna bulbs in a standard kitchen refrigerator is generally not recommended because it is usually too cold and too dry. Most refrigerators are kept around 35°F to 38°F, which can damage the tender tropical tissue of the rhizome over several months. Additionally, refrigerators lack the ventilation needed to prevent mold, and the presence of certain fruits can release gases that interfere with the plant's dormancy.

Do I have to wash the dirt off before storing?

No, you do not have to wash the dirt off, and many gardeners find that leaving a little bit of dry soil on the rhizome actually helps protect it. If the soil is very muddy or contains pests, you may want to rinse it off, but you must ensure the rhizome is completely dry before packing it away. If you leave the soil on, just let it dry and gently brush off the largest clumps before storage.

What happens if I forget to dig them up before the ground freezes?

If the ground freezes solid before you dig your cannas, there is a high risk that the rhizomes will be damaged beyond repair. Canna rhizomes are very fleshy and hold a lot of water; when that water freezes, the cells burst, and the rhizome will turn into a mushy mess once it thaws. If you experience a light frost that only affects the surface of the soil, your rhizomes are likely still fine, but you should dig them up as soon as possible.

Can I store cannas that were grown in containers?

Yes, container-grown cannas are actually the easiest to store. Once the foliage has been hit by frost, cut the stems back to a few inches above the soil line. You can then move the entire pot into a cool, frost-free area like a basement or crawl space. You don't need to water the pot at all during the winter; simply let the soil dry out and let the plant remain dormant in its own container until spring.