Successful Winter Storage of Canna Bulbs

Table of Contents

1. Introduction
2. Why Storage of Canna Bulbs is Worth the Effort
3. Determining if You Need to Dig
4. When to Dig Your Canna Rhizomes
5. Tools You Will Need
6. How to Dig Canna Bulbs Safely
7. Cleaning and Preparing for Storage
8. The Importance of Curing
9. Choosing the Best Packing Material
10. Finding the Perfect Storage Location
11. Monitoring Your Bulbs Throughout the Season
12. Storing Container-Grown Cannas
13. Preparing for Spring Replanting
14. Summary of Success
15. FAQ

Introduction

Walking through a summer garden filled with cannas feels like visiting a tropical paradise. Their oversized, paddle-like leaves and brilliant blooms in shades of red, orange, and yellow create a bold statement that few other plants can match. At Longfield Gardens, we enjoy how these vigorous plants transform a backyard into a lush retreat. The best part is that you do not have to buy new plants every year. By mastering the storage of canna bulbs, you can save your favorite varieties and enjoy even bigger, more beautiful displays each passing summer.

This guide provides everything you need to know about digging, cleaning, and overwintering your canna rhizomes. Whether you are a beginner or a seasoned gardener, these steps will help you preserve your plants through the coldest months. Learning to store these tender perennials is a rewarding way to build your canna collection over time. With a little bit of preparation in the fall, you will be ready for a spectacular planting season when spring returns.

Why Storage of Canna Bulbs is Worth the Effort

Cannas are remarkably resilient plants during the heat of summer, but they have one significant weakness. They are tropical in origin and cannot survive freezing temperatures. In many parts of the United States, the winter ground gets cold enough to turn these fleshy rhizomes into mush. Storing them indoors is the simplest way to ensure they return next year.

Saving your rhizomes is also a fantastic way to get more value out of your garden. A single canna rhizome planted in the spring often grows into a massive clump by the end of the summer. When you dig them up in the fall, you will likely find that your one plant has multiplied into several. This means you can expand your garden or share extra plants with friends and neighbors.

The process of overwintering also gives you a head start on the next growing season. Since the rhizomes you store are already mature, they often sprout faster and bloom earlier than newly purchased ones. It is a satisfying cycle that connects your garden across the seasons. For more background on growing and planting, see our All About Cannas guide.

Determining if You Need to Dig

The first step in the storage of canna bulbs is knowing if your climate requires it. Cannas grow from rhizomes, which are thick, horizontal underground stems. These structures store energy for the plant, but they are full of water, making them very sensitive to ice and frost.

Check Your USDA Hardiness Zone

In the United States, your location determines whether your cannas can stay in the ground. If you live in USDA zones 8 through 10, your soil typically stays warm enough that cannas can remain outdoors. In these warmer regions, you can simply cut the foliage back after it yellows and perhaps add a layer of mulch for extra protection. Our USDA Hardiness Zone Map can help you check your climate.

If you live in zone 7, you are in a "middle ground" area. Many gardeners in zone 7 find that their cannas survive if they are planted in a protected spot, such as near a south-facing wall. However, a particularly cold winter can still kill them. Many people in this zone choose to dig up their most prized tall cannas just to be safe.

For gardeners in zones 6 and colder, digging and storage are necessary. In these regions, the frost penetrates deep into the soil. Without intervention, the rhizomes will freeze and rot. Taking the time to bring them inside is the only way to keep them alive for the following year.

When to Dig Your Canna Rhizomes

Timing is one of the most important factors for successful 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 a deep freeze sets in.

Watch the Foliage

The ideal time to dig is right after the first "killing frost." This is a light frost that turns the lush green leaves brown or black but does not freeze the ground. This frost acts as a natural signal to the plant. It tells the canna that the growing season is over and it is time to go dormant. For more timing details, see our guide on when to dig up canna lily bulbs.

If your local weather forecast predicts a hard freeze where temperatures will stay well below freezing for several hours, do not wait. It is better to dig the rhizomes a few days early than to let them freeze in the ground. If the rhizome itself freezes, the cells will rupture, and the plant will rot.

Using Nature’s Schedule

Waiting for that first light frost is beneficial because the plant continues to move nutrients from the leaves down into the rhizome until the very last moment. This extra energy helps the rhizome stay healthy during its long winter nap. However, if you have a busy schedule and need to dig them a week or two before the first frost, the plants will usually be fine. They are adaptable and will go dormant once they are removed from the soil and kept in a dark place.

Key Takeaway: Wait for the first light frost to turn the leaves brown before digging. This signal helps the plant enter a natural state of dormancy for the winter.

Tools You Will Need

Before you head out to the garden, gather a few basic tools. Having everything ready makes the process much smoother and faster.

• A garden fork or spade: A garden fork is often preferred because it is less likely to slice through the rhizomes.
• Pruning shears or a sharp knife: You will need these to cut back the heavy stalks.
• A garden hose: This is useful for rinsing away excess soil, though it is not always required.
• Storage containers: Cardboard boxes, plastic bins with air holes, or breathable mesh bags all work well.
• Packing material: Options include peat moss, vermiculite, wood shavings, or even simple newspaper.
• Labels and a marker: It is very easy to forget which variety is which once the leaves are gone.

How to Dig Canna Bulbs Safely

When you are ready to dig, the goal is to lift the entire clump without causing damage. Canna rhizomes are sturdy, but they can be bruised or cut if you are too aggressive with your tools.

Clear the Foliage

Start by cutting the stalks down. Use your pruning shears to cut the stems about 2 to 4 inches above the soil line. Leaving a small amount of stem gives you a "handle" to grab and makes it easier to see where the rhizomes are located. Dispose of the old foliage in your compost pile or green waste bin, provided the plants were healthy and free of pests.

Loosen the Soil

Canna rhizomes can spread quite far from the original planting spot. To avoid hitting them with your shovel, start digging about 6 to 12 inches away from the base of the stems. Sink your garden fork or spade deep into the soil and gently pry upward.

Work your way around the entire clump, loosening the soil as you go. You want to lift the whole mass at once. If the clump is very large and heavy, you can use the fork to gently break it into smaller, more manageable sections while it is still in the ground, but be careful not to chop through the main growing points.

Lift and Inspect

Once the soil is loose, lift the clump out of the ground. Use your hands to shake off the big chunks of dirt. At this stage, take a quick look at the rhizomes. They should feel firm and heavy. If you see any parts that are soft, mushy, or clearly damaged, you can trim those sections off now. Healthy rhizomes are typically a light tan or white color under the dirt.

Cleaning and Preparing for Storage

There are two schools of thought when it comes to cleaning canna rhizomes: the "dry brush" method and the "rinse" method. Both can be successful, and the choice often depends on your soil type.

The Rinse Method

If you have heavy clay soil, the dirt often sticks to the rhizomes in large clumps. In this case, using a garden hose to gently wash away the soil is very helpful. Rinsing allows you to see the health of the rhizomes clearly and makes it easier to spot any hidden pests. If you choose to rinse, it is vital that you allow the rhizomes to dry thoroughly before packing them away.

The Dry Brush Method

In sandy or loose soil, the dirt often falls away naturally. You can simply let the clumps sit in the sun for an hour or two and then use your hands or a soft brush to knock off the remaining soil. This method is faster and avoids adding extra moisture to the rhizomes right before storage.

Trimming and Dividing

After cleaning, you may want to trim the small, hair-like roots hanging off the rhizomes. While not strictly necessary, it makes the rhizomes cleaner and easier to pack.

You can also divide the clumps now if you want to. Look for the "eyes" or growing points on the rhizomes. As long as each piece has at least one or two healthy eyes, it will grow into a new plant next year. Some gardeners prefer to wait until spring to divide, as the eyes are easier to see when they begin to swell with new growth. If you do divide them in the fall, let the cut ends dry for a few extra days to "callous" over. For more step-by-step care, see our guide on how to care for canna lily bulbs.

The Importance of Curing

Curing is the process of letting the outer skin of the rhizome toughen up. This is a critical step in the storage of canna bulbs because it helps prevent rot and desiccation (drying out too much).

Place your cleaned rhizomes in a dry, well-ventilated area that is out of direct sunlight. A garage, a covered porch, or a basement floor works well. Spread them out in a single layer so that air can circulate around each piece.

The curing process usually takes between 2 and 7 days. You will know they are ready when the outer skin feels dry and slightly papery, and any remaining soil has turned into a dry powder. Curing creates a protective barrier that keeps the internal moisture inside the rhizome while keeping mold spores out.

What to do next:

1. Cut stems to 3 inches above the soil.
2. Lift the clump from 10 inches away to avoid damage.
3. Shake or rinse off the soil.
4. Let the rhizomes air-dry in a cool, shaded spot for 3 to 5 days.

Choosing the Best Packing Material

Once your rhizomes are cured, it is time to pack them for the winter. You cannot simply leave them in an empty box, as they will likely dry out and shrivel. The goal is to provide a medium that maintains a tiny bit of moisture while still allowing the rhizomes to breathe.

Peat Moss and Vermiculite

Peat moss is one of the most popular choices because it is naturally acidic and helps inhibit mold. Vermiculite is another great option as it holds moisture very well without becoming soggy. If you use these materials, they should be "barely damp." A good rule of thumb is the "wrung-out sponge" test: if you squeeze a handful of the material, no water should drip out, but it should feel cool and moist to the touch.

Wood Shavings or Sawdust

Pine or cedar shavings (the kind sold for pet bedding) are excellent for storage. They are clean, easy to handle, and provide great insulation. They also allow for good air circulation, which is key to preventing rot.

Newspaper

If you are looking for a low-cost option, newspaper works surprisingly well. You can wrap each individual rhizome in a few layers of dry newspaper and then stack them in a box. The paper absorbs excess moisture but keeps the rhizomes from touching each other, which prevents a single spot of rot from spreading to the whole batch.

Finding the Perfect Storage Location

Where you put your boxes of cannas is just as important as how you pack them. You are looking for a "Goldilocks" environment: not too hot, not too cold, and not too wet.

Temperature is Key

The ideal temperature for storing canna rhizomes is between 40°F and 50°F.

• Too Cold: If the temperature drops below 35°F, you risk the rhizomes freezing.
• Too Hot: If the temperature stays above 55°F, the rhizomes may think it is spring and start to grow prematurely, which depletes their energy.

Common Storage Spots

• Unheated Basements: Usually the best option, as they stay cool and relatively humid.
• Crawl Spaces: These often have the perfect temperature, but make sure they are not too damp.
• Attached Garages: These can work well, but you must ensure the box is not sitting directly on a cold concrete floor. Place the box on a shelf or a piece of wood to provide insulation.
• Root Cellars: These are traditional for a reason; they provide the stable, cool temperatures cannas love.

Avoid storing your cannas in an attic, as these spaces often fluctuate wildly in temperature, becoming very hot during sunny winter days and freezing at night.

Monitoring Your Bulbs Throughout the Season

Storage of canna bulbs is not a "set it and forget it" task. To ensure a high success rate, you should check on your rhizomes about once a month. This only takes a few minutes but can save your entire collection.

Checking for Rot

Open your containers and look for any signs of mold or mushiness. If you find a rhizome that is starting to rot, remove it immediately so it does not infect the others. If only a small tip is soft, you can cut it off with a clean knife and let the healthy portion dry out before putting it back.

Checking for Desiccation

If the rhizomes feel very light and look shrivelled like a prune, they are getting too dry. In this case, use a spray bottle to lightly mist the packing material. You do not want it to be wet, just enough to raise the humidity inside the box.

It is normal to lose a few rhizomes over the winter. Even professional gardeners expect a small percentage of loss. If 80% to 90% of your rhizomes make it through to spring, you have done an excellent job.

Storing Container-Grown Cannas

If you grow your compact cannas in pots, the storage process is even easier. You have two main options for overwintering container plants.

The "Dry Pot" Method

The simplest way is to let the pot go dormant. After the first frost kills the leaves, cut the stalks down to the soil line. Instead of digging the rhizomes out, simply move the entire pot into a cool, frost-free area like a basement or garage. Stop watering the pot entirely. The soil will dry out, and the rhizomes will sleep comfortably in the pot all winter. In the spring, you can pull them out, refresh the soil, and start watering again.

The Dig and Store Method

If your medium cannas have become "root-bound" (filling the entire pot with roots and rhizomes), it is better to dig them up. Container-grown cannas multiply rapidly, and they can sometimes crack plastic pots or become so tight that they stop blooming. Digging them up allows you to divide them and give them more space for the next season.

Preparing for Spring Replanting

As winter fades and the ground begins to warm, your canna bulbs will start to wake up. This is the most exciting part of the process!

Timing the Return

Do not be in too much of a hurry to plant your cannas outside. They love warm soil. Wait until the danger of frost has completely passed and the soil temperature is at least 60°F. In most regions, this is around the same time you would plant tomatoes or peppers. If you are ordering ahead, our Shipping Information page explains timing by zone.

Waking Them Up Early

If you want blooms even earlier, you can "start" your rhizomes indoors about 4 to 6 weeks before the last frost. Place them in pots with some potting soil and put them in a warm, sunny window. By the time the weather is warm enough to move them outside, you will already have several inches of lush green growth. For more container ideas, see our How to Grow Summer Bulbs in Containers.

Checking for Quality

Before planting, give each rhizome a final squeeze. It should be firm. Any that are completely hollow or mushy should be discarded. We at Longfield Gardens recommend looking for those healthy "eyes" or sprouts to ensure you are planting the most vigorous pieces.

Key Takeaway: Success comes from a balance of moisture and coolness. Check your stored rhizomes monthly to ensure they are neither rotting nor drying out completely.

Summary of Success

The storage of canna bulbs is a straightforward process that becomes easier every year you do it. By following the natural cues of the seasons, you can preserve these tropical beauties and watch your garden grow more impressive with each passing summer. For more information about how we stand behind our plants, see our 100% Quality Guarantee.

• Wait for the first light frost to signal dormancy.
• Dig carefully and cure the rhizomes for a few days to toughen the skin.
• Store in a cool, dark place (40-50°F) using a breathable medium like peat moss or shavings.
• Check monthly and adjust moisture levels if necessary.

Gardening is a journey of learning and observation. While every winter is a little different, these basic steps provide a reliable foundation for keeping your cannas healthy. We look forward to seeing your garden burst into tropical color once the spring sun returns.

FAQ

Can I store canna bulbs in the refrigerator?

While a refrigerator provides the cool temperatures cannas need, it is generally too cold and too dry for long-term storage. Most refrigerators are kept around 35-37°F, which is very close to the freezing point that damages rhizomes. Additionally, the lack of humidity can cause them to shrivel quickly. A cool basement or insulated garage is a much better choice.

Do I have to wash the dirt off the rhizomes?

No, washing is not strictly required. Many gardeners prefer to leave a little bit of soil on the rhizomes, as it can act as a natural protective layer. However, if your soil is very wet or heavy clay, rinsing it off makes it easier to inspect for rot and pests. If you do wash them, ensure they are 100% dry before you pack them away for the winter.

What happens if I dig my cannas before the first frost?

Your cannas will still survive if you dig them early. While waiting for the frost is ideal because it ensures the plant has finished its growth cycle, you can dig them up whenever your schedule allows in the late fall. The rhizomes will naturally enter dormancy once they are removed from the light and warmth of the garden.

My stored canna bulbs have white mold on them, are they ruined?

Not necessarily. A small amount of fuzzy white mold on the surface is often a sign that the storage medium is a bit too damp or there isn't enough airflow. You can wipe the mold off with a soft cloth and a diluted solution of water and a little bit of dish soap or vinegar. Allow the rhizomes to air-dry for a day before repacking them in fresh, drier material. If the rhizome itself is soft and mushy, however, that piece should be discarded.