Do I Have to Dig Up Canna Bulbs?

Table of Contents

1. Introduction
2. Understanding Canna Hardiness and Your Climate
3. When to Dig Up Canna Bulbs
4. How to Dig and Clean Canna Rhizomes
5. Curing and Preparing for Storage
6. Best Methods for Winter Storage
7. Caring for Cannas in Warm Climates (Zones 8-11)
8. Managing Container-Grown Cannas
9. Dividing Your Cannas for More Plants
10. Common Myths About Canna Storage
11. Replanting in the Spring
12. Troubleshooting Winter Storage Issues
13. Why Quality Matters
14. Conclusion
15. FAQ

Introduction

There is something truly magical about the way cannas transform a summer garden. With their lush, banana-like leaves and vibrant, tropical blooms, they bring an exotic energy to any landscape, whether you are planting them in garden beds or large patio containers. We love how these high-impact plants perform during the hottest days of August when other flowers might begin to fade. At Longfield Gardens, we want to help you enjoy that tropical beauty year after year, which leads to one of the most common questions we receive: do I have to dig up canna bulbs in the fall?

The answer to this question depends almost entirely on where you live and how cold your winters get. While cannas are vigorous growers, they are tropical plants at heart and cannot survive freezing ground temperatures. This guide will help you determine the best winter plan for your specific location, whether that means leaving your plants in the ground or tucking them away safely for the winter. By understanding a few simple rules about temperature and storage, you can keep your canna collection growing bigger and better every season.

Whether you are a first-time canna grower or a seasoned gardener looking to refine your technique, the following steps will take the guesswork out of winter care.

Understanding Canna Hardiness and Your Climate

To decide if you need to dig up your canna rhizomes (which many gardeners commonly call "bulbs"), you first need to know your USDA Plant Hardiness Zone. These zones are based on the average minimum winter temperature in your area. Because cannas are native to tropical and subtropical regions, they have not evolved to survive deep freezes.

In general, canna rhizomes are hardy in zones 8 through 11. In these warmer regions, the ground rarely freezes deep enough to damage the rhizomes. If you live in these zones, you can typically leave your cannas in the ground all year long. They will go dormant when temperatures drop, then sprout again once the soil warms up in the spring.

If you live in zones 3 through 6, the ground will freeze solid during the winter months. This freezing action turns the moisture inside the canna rhizome into ice, which destroys the plant tissue and causes the bulb to rot. In these cooler climates, digging them up is a necessary step if you want to save the plants for next year. Zone 7 is considered a "swing" zone; in a mild winter with heavy mulching, cannas might survive, but most gardeners find it safer to lift them.

Key Takeaway: Your local winter temperature is the biggest factor. If your ground freezes, your cannas need to come indoors. If your soil stays frost-free, they can stay in the garden.

When to Dig Up Canna Bulbs

Timing is everything when it comes to lifting cannas. You want to give the plants as much time as possible to store energy in their rhizomes, but you must get them out of the ground before a hard, deep freeze sets in.

The best signal to start the process is the first frost of autumn. You will notice that the once-vibrant green or bronze foliage turns black or wilted after a night of freezing temperatures. This is perfectly normal and does not mean the plant is dead; it simply means the foliage has finished its job for the year.

Once the foliage has been "zapped" by frost, the plant enters its dormant phase. It is often best to wait a few days after this first frost before digging. This allows the nutrients from the dying leaves to travel down into the rhizome, providing a little extra fuel for next year's growth. However, do not wait until the ground itself freezes solid, as this can damage the rhizomes and make digging much more difficult.

Steps to Take Before You Dig

• Monitor your local weather forecast for the first "killing frost."
• Gather your tools: a garden fork or spade, sharp bypass pruners, and a way to label your varieties.
• Prepare a space in a garage, basement, or crawlspace that stays cool but remains above freezing (ideally between 40°F and 50°F).

How to Dig and Clean Canna Rhizomes

When you are ready to lift your cannas, the goal is to remove the rhizomes from the soil without bruising or cutting them. Canna rhizomes are thick, fleshy structures that grow horizontally just beneath the soil surface. They can become quite large and heavy by the end of a successful growing season.

Start by cutting the stalks down to about 2 to 4 inches above the soil line using your pruners. This gives you a "handle" to hold onto and makes the clump easier to manage. Next, use a garden fork to gently loosen the soil in a circle about 6 to 12 inches away from the base of the plant. A garden fork is often better than a shovel because it is less likely to slice through the rhizomes.

Once the soil is loose, lift the entire clump out of the ground. Don't be surprised if the clump is much larger than the single rhizome you planted in the spring! Use your hands to knock off the large chunks of soil. You do not need to scrub them perfectly clean, but removing the bulk of the dirt helps them dry faster and prevents soil-borne diseases from lingering during storage.

What to Do Next:

• Cut stalks to 3 inches above the rhizome.
• Loosen soil in a wide circle to avoid damage.
• Gently lift the clump and shake off excess soil.
• Label each clump immediately so you remember the colors and heights next spring.

Curing and Preparing for Storage

After digging, canna rhizomes need a short period of "curing." Curing is simply letting the rhizomes air-dry so the outer skin can toughen up slightly. This step is vital because it helps prevent rot during the long winter months.

Place your cleaned clumps in a dry, shaded area—like a porch or a well-ventilated garage—for one to two days. Avoid leaving them in direct sunlight, as this can cause them to dry out too quickly and shrivel. You want the surface to feel dry to the touch, but the rhizome itself should still feel heavy and firm.

While you are cleaning and curing, take a moment to inspect the rhizomes. If you see any soft spots, mushy areas, or signs of insect damage, use a clean knife to trim those parts away. A healthy rhizome should be light-colored inside and firm, similar to a potato. If a clump has grown particularly large, you can break it into smaller sections, provided each section has at least one or two "eyes" (the small bumps where new growth will emerge).

Best Methods for Winter Storage

The key to successful canna storage is finding the right balance of moisture. If the storage environment is too wet, the rhizomes will rot. If it is too dry, they will shrivel up and lose their vitality.

We recommend nesting the rhizomes in a moisture-retaining material. Common choices include:

• Peat moss
• Vermiculite
• Coarse sawdust or wood shavings
• Shredded newspaper

Place a layer of your chosen material in the bottom of a cardboard box, plastic bin with air holes, or a paper grocery bag. Arrange the rhizomes in a single layer so they aren't touching, then cover them with more material. If you have a large collection, you can stack layers, but ensure there is plenty of packing material between them.

Store the containers in a dark, cool place where the temperature stays consistently between 40°F and 50°F. An unheated basement or a temperature-controlled crawlspace is usually ideal. Avoid storing them near a furnace or in a spot where the temperature fluctuates wildly.

Key Takeaway: Check your stored rhizomes once a month during the winter. If they look shriveled, lightly mist the packing material with water. If you see any soft spots or mold, remove the affected piece immediately to keep the rest of the batch healthy.

Caring for Cannas in Warm Climates (Zones 8-11)

If you are lucky enough to live in a region where you don't have to dig up your canna bulbs, your winter chores are much simpler. Even though the plants stay in the ground, they still benefit from a little end-of-season care to ensure they return vigorously in the spring.

Once the foliage begins to yellow or brown in late autumn, you can cut the stalks down to the ground. This cleans up the garden bed and prevents old foliage from harboring pests or diseases over the winter. In Zone 8, where a surprise frost might occur, it is a good idea to apply a 3-to-4-inch layer of mulch—such as straw, bark, or shredded leaves—over the top of the planting area. This mulch acts like a blanket, keeping the soil temperature stable.

In these warmer zones, drainage becomes the most important factor during the winter. Cannas like plenty of water during the growing season, but if they sit in cold, soggy soil during their dormant period, the rhizomes can rot. Ensure your garden beds have good drainage so that winter rains don't pool around the dormant plants.

Winter Maintenance Checklist for Warm Zones

• Cut back dead foliage after the first chill.
• Apply a fresh layer of mulch for insulation.
• Avoid over-watering while the plants are dormant.
• Check for adequate drainage during the rainy season.

Managing Container-Grown Cannas

Many gardeners choose to grow cannas in pots to add height and drama to patios. If you live in a cold climate, you have two choices for your container-grown cannas.

First, you can treat them exactly like garden plants. This involves digging the rhizomes out of the pot, cleaning them, and storing them in peat moss as described earlier. This is often the best choice if your pots are too large to move or if you want to reuse the pots for winter evergreen displays.

The second option is to move the entire pot into a frost-free area, such as a basement or garage. If you choose this method, cut the stalks back to the soil level and stop watering entirely once you move the pot indoors. The soil in the pot will act as the storage medium. In the spring, you can move the pot back outside, give it a good soak of water, and wait for the new shoots to appear.

Note that cannas are fast growers and can become "pot-bound" quickly. Even if you store them in their pots, every two or three years you should tip the pot over, remove the rhizome clump, and divide it. This prevents the roots from becoming too crowded and ensures the plant continues to bloom well.

Dividing Your Cannas for More Plants

One of the most rewarding parts of growing cannas is how quickly they multiply. When you dig up your rhizomes in the fall, you will likely find that one rhizome has turned into a large clump with several offshoots. Digging and storing provides the perfect opportunity to divide these clumps and expand your garden for free.

You can divide cannas either in the fall before you put them into storage or in the spring before you replant. Using a clean, sharp knife or your hands, break the rhizome clump into smaller pieces. Each piece must have at least one "eye," which is a small, raised point or bud where the new stem will grow.

Large, healthy rhizomes produce the strongest plants and the most flowers. When dividing, try to keep pieces that are about the size of a large potato. This gives the new plant plenty of stored energy to start growing quickly once the weather warms up.

What to Do Next:

• Identify the "eyes" on the rhizome clump.
• Use a sharp knife to create sections with 1–3 eyes each.
• Allow any cut surfaces to dry for 24 hours before storing or planting.
• Share extra rhizomes with friends or use them to fill new areas of your yard.

Common Myths About Canna Storage

There are many "internet hacks" and myths regarding canna care that can lead to confusion. Let's clear up a few of the most common ones.

One common myth is that you must wash canna rhizomes with bleach or chemicals before storing them. In reality, this is rarely necessary and can sometimes damage the delicate eyes of the plant. As long as you remove the bulk of the soil and allow the rhizomes to dry properly, they should store just fine without chemical intervention.

Another misconception is that cannas will "bloom better" if they aren't dug up. While established clumps in warm climates can be very productive, cannas grown from stored rhizomes in the north will bloom just as beautifully. The key is providing them with plenty of sun, water, and fertilizer once they are replanted in the spring.

Finally, some believe that canna rhizomes need to be kept in the dark to stay dormant. While a dark spot like a basement is ideal, the temperature is far more important than the light level. If it stays cool, the plant will remain dormant. If it gets too warm, the plant may try to sprout early, regardless of whether it is in the dark or not.

Replanting in the Spring

The cycle of canna care comes full circle in the spring. Once the danger of frost has passed and the soil has warmed to at least 60°F, you can bring your rhizomes out of storage. At Longfield Gardens, we recommend waiting until the weather is consistently warm before planting outdoors, as cannas really don't like cold soil.

If you want a head start on the season, you can "start" your rhizomes indoors about four to six weeks before the last frost date. Simply plant them in pots with high-quality potting soil and place them in a sunny window or under grow lights. This gives the plants time to develop roots and a few inches of green growth, so they are ready to take off the moment they hit the garden.

When planting, place the rhizomes horizontally in the soil, about 4 to 5 inches deep. Space taller varieties like Canna Tall Australia about 2 feet apart and smaller dwarf varieties like Canna Medium Banana Punch about 1 foot apart. Give them a good drink of water to settle the soil, and then wait for those first tropical leaves to unfurl.

Troubleshooting Winter Storage Issues

Even with the best care, you might occasionally run into a few hurdles during the winter. The most common issue is rot. If you check your rhizomes and find some that are soft, slimy, or smell bad, it usually means they were too wet when they went into storage or the packing material was too damp.

If you catch rot early, you can often save the rest of the clump by cutting away the bad parts and letting the healthy section dry out for a day before repacking it in fresh, dry peat moss.

On the other hand, if the rhizomes feel very light and look shriveled like a raisin, they have lost too much moisture. You can try to revive them by soaking them in lukewarm water for a few hours, then repacking them in slightly more damp material.

Remember, gardening is a learning process, and every microclimate is different. If one storage method doesn't work perfectly the first year, try adjusting the moisture levels or the location next year. Most cannas are quite resilient and will forgive a few minor mistakes.

Why Quality Matters

The success of your winter storage actually begins with the quality of the plants you choose in the spring. Healthy, vigorous rhizomes that have been grown and stored correctly by professionals will produce stronger plants that are better able to handle the stresses of dormancy.

We work with experienced growers to ensure that the rhizomes we provide are true to variety and arrive in prime condition. When you start with high-quality stock from Longfield Gardens, you are giving yourself a head start. These robust plants develop larger root systems and thicker rhizomes by the end of the summer, making them much easier to store through the winter.

Investing in top-tier varieties also means you get the best flower production and the most striking foliage colors. Whether you prefer the dark, moody leaves of Australia or the bright, spotted blooms of Canna Assorted Collection, starting with healthy plants is the best way to ensure a spectacular garden year after year.

Conclusion

Determining whether you have to dig up your canna bulbs is one of the most important steps in maintaining a beautiful tropical garden. While it requires a bit of effort in the fall for those in colder climates, the reward of seeing those giant, colorful leaves return every summer is well worth the work. By matching your care to your USDA zone and following a simple routine of lifting, cleaning, and storing, you can preserve your favorite varieties for a lifetime of garden enjoyment.

• Know your zone: Dig in Zones 3-7; leave in ground in Zones 8-11.
• Wait for frost to blacken the foliage before digging.
• Store in a cool, dry, frost-free location with peat moss or sawdust.
• Divide large clumps to expand your garden for free.

Growing cannas should be a rewarding experience that adds a sense of adventure to your landscape. With just a little bit of seasonal planning, these tropical beauties will continue to be the stars of your summer garden.

Ready to add some tropical flair to your yard? Explore the Canna Tall collection and the full canna collection at Longfield Gardens today.

FAQ

How do I know if my canna bulbs are still good after winter?

Healthy rhizomes should feel heavy and firm to the touch, similar to a fresh potato or ginger root. When you look closely, you should see small, firm "eyes" or buds. If the rhizome is mushy, smells bad, or crumbles when squeezed, it has likely rotted or dried out completely and should be discarded.

Can I store cannas in the refrigerator?

While a refrigerator provides a cool environment, it is generally not recommended for canna storage. Refrigerators are often too cold (below 40°F) and the air is very dry, which can cause the rhizomes to shrivel. Additionally, some fruits and vegetables in the fridge release gases that can damage dormant flower bulbs.

Do I need to water my cannas while they are in winter storage?

Generally, no. The goal of storage is to keep the rhizomes dormant. However, you should check them once a month. If the rhizomes look very shriveled and the packing material is bone-dry, you can lightly mist the peat moss or sawdust with a spray bottle to provide a tiny amount of moisture.

What happens if I forget to dig up my cannas in a cold zone?

If you live in a zone where the ground freezes (Zone 6 or lower) and you leave your cannas in the ground, the rhizomes will almost certainly die. The freezing temperatures turn the water inside the rhizome into ice, which ruptures the plant's cells. In the spring, the rhizome will simply turn into a soft, mushy mass and will not regrow.

For help choosing the right plants and timing your order, see our Shipping Information and 100% Quality Guarantee pages, or read more in All About Cannas and Know Your Growing Zone: Cold Hardiness and Heat Tolerance.