Digging Up Canna Bulbs for Success Next Season

Table of Contents

1. Introduction
2. Why We Dig Up Canna Bulbs
3. Timing Your Harvest Correctly
4. Tools and Preparation
5. Step-By-Step Guide to Digging Up Canna Bulbs
6. The Curing Process
7. Storing Your Cannas for Winter
8. Winter Maintenance and Care
9. Dividing for More Blooms
10. Storing Potted Cannas
11. Preparing for Spring
12. Conclusion
13. FAQ

Introduction

Canna lilies are the undisputed heavyweights of the summer garden, offering a bold, tropical flair that few other plants can match. At Longfield Gardens, we love how their oversized foliage and vibrant blooms turn even the most modest backyard into a lush getaway. Because these plants are native to warm, tropical climates, they thrive in the heat of July and August. However, for gardeners in many parts of the United States, the arrival of autumn means it is time to plan for the winter months. For more warm-season options, browse our Spring-Planted Summer-Blooming Bulbs.

If you live in a region where the ground freezes, digging up canna bulbs is the best way to ensure these beautiful plants return to your garden next year. While they are technically rhizomes—thick, fleshy underground stems—rather than true bulbs, the process of harvesting and storing them is quite simple. This guide is designed for home gardeners who want to protect their investment and enjoy their favorite canna varieties for many seasons to come. By following a few straightforward steps, you can successfully transition your cannas from the garden bed to winter storage.

Why We Dig Up Canna Bulbs

The primary reason for digging up cannas is their sensitivity to cold temperatures. Most canna varieties are hardy only in USDA zones 8 through 11. In these warmer climates, the soil stays warm enough through the winter that the rhizomes can remain in the ground. However, in zones 7 and colder, the freezing winter temperatures will damage or destroy the fleshy rhizomes if they are left unprotected. See the Hardiness Zone Map if you need to check your climate zone.

Digging up your cannas is also a wonderful opportunity to grow your garden collection. Over a single growing season, a healthy canna plant will produce several new offshoots underground. When you dig them up in the fall, you will likely find that your one original plant has turned into a large clump. By harvesting these, you can divide them and have twice as many plants to place around your yard next spring. It is a rewarding way to see your garden’s progress firsthand. For a ready-made mix, see the Canna Assorted Mix - Bulk Offer.

Timing Your Harvest Correctly

Knowing exactly when to start digging up canna bulbs is the secret to a successful harvest. In gardening, timing often matters more than complex techniques. For cannas, the signal to begin comes directly from nature in the form of the first autumn frost.

The Frost Signal

While you can dig up cannas as soon as the leaves begin to yellow in late fall, most gardeners wait for the first light frost. This frost will usually turn the lush green or bronze foliage to a dark brown or black color. While it might look like the plant has died, the rhizome underground is perfectly safe. In fact, this period of cooling helps the plant understand that it is time to go dormant.

Waiting for that first frost allows the plant to spend the entire summer and early fall storing energy. The longer the leaves are active, the more nutrients they can pump down into the rhizome. These stored starches are what the plant will use to push out new growth next spring. However, you should aim to dig them up before the ground itself freezes solid. A light surface frost is a helpful signal, but a deep, hard freeze that penetrates several inches into the soil can damage the rhizomes.

Checking Your Hardiness Zone

If you are unsure whether you need to dig up your bulbs, a quick check of your USDA hardiness zone is helpful.

• Zones 8-11: You can typically leave cannas in the ground. Adding a thick layer of mulch in late fall provides extra protection.
• Zone 7: This is the "swing" zone. In mild winters or protected microclimates (like a south-facing wall), cannas may survive with heavy mulching. However, many gardeners dig them up just to be safe.
• Zones 3-6: Digging up the rhizomes is necessary. The ground in these regions freezes deep enough to reach the bulbs, which will cause them to rot once the soil thaws.

Tools and Preparation

Before you head out to the garden, gather a few basic tools. Having everything ready makes the process quick and prevents unnecessary damage to the plants.

• A Garden Fork or Spade: A garden fork is often better than a shovel because it is less likely to slice through the rhizomes. If you use a spade, you will need to be extra careful with your placement.
• Pruning Shears or a Garden Knife: You will need these to cut back the heavy stalks.
• A Garden Hose: Useful for rinsing off excess soil.
• Identification Tags: It is very easy to forget which rhizome is which once the leaves are gone. We recommend having some string tags or a permanent marker and masking tape ready to label your varieties.
• Gloves: Canna stalks can be juicy and messy, and digging in the soil is always easier with a good pair of gardening gloves.

Key Takeaway: The goal of harvesting is to keep the rhizomes intact. Using a garden fork instead of a sharp shovel reduces the risk of accidentally cutting into the fleshy "eyes" of the bulb, which are the points where new growth will emerge.

Step-By-Step Guide to Digging Up Canna Bulbs

Once the first frost has blackened the foliage, you can begin the harvesting process. Follow these steps for a smooth and successful dig.

Step 1: Cut Back the Foliage

Before you touch the soil, use your pruning shears to cut the canna stalks down. Leave about 4 to 6 inches of the stalk remaining above the soil line. These short "handles" make it much easier to see where the plant is located and give you something to hold onto while you lift the clump. Discard the frosted leaves and upper stalks in your compost pile or green waste bin, provided they show no signs of disease.

Step 2: Loosen the Soil

Cannas grow outward as well as downward. The rhizomes can spread significantly during the summer, so it is important not to dig too close to the center of the plant. Start your digging about 10 to 12 inches away from the base of the stalks.

Push your garden fork or spade deep into the soil and gently rock it back and forth to loosen the earth. Work your way in a circle around the entire clump. This gradual loosening prevents the rhizomes from snapping under pressure. For planting-time spacing, see How Far Apart Should Canna Bulbs Be Planted?.

Step 3: Lift the Clump

Once you have loosened the soil all the way around, slide your tool underneath the clump and gently pry it upward. You may need to do this from a few different angles to get the whole mass to move. Lift the entire clump out of the ground.

Don't worry if the clump is very large and heavy. At this stage, it is better to lift it as one piece rather than trying to break it apart while it is still buried in the dirt.

Step 4: Remove Excess Soil

Shake the clump gently to remove large clods of dirt. If your soil is heavy clay, the dirt might stick stubbornly to the rhizomes. You can use your hands to pull away the larger pieces of soil.

At this point, some gardeners prefer to use a garden hose to rinse the rhizomes clean. Rinsing makes it easier to see the condition of the bulbs and helps you spot any "eyes" or potential pests. However, if you rinse them, you must be very diligent about the drying process in the next phase.

Step 5: Initial Inspection and Labeling

Take a moment to look at your harvested rhizomes. They should feel firm to the touch, similar to a fresh potato. If you find any parts that are soft, mushy, or obviously damaged, you can trim those sections off with a clean knife.

Immediately label your plants. You can write the variety name directly on the remaining stalk with a permanent marker or tie a tag around it. If you have several different colors or heights of cannas, you will be very glad you did this when planting time arrives next spring.

What to do next:

• Cut stalks to 4-6 inches.
• Dig 12 inches away from the stem to avoid damage.
• Lift the entire clump carefully.
• Shake or rinse off the heavy soil.
• Label each variety clearly.

The Curing Process

Curing is a vital step that many beginners overlook. Curing simply means letting the rhizomes dry out slightly before they go into long-term storage. This process allows the outer "skin" of the rhizome to toughen up, which acts as a natural barrier against rot and mold.

Place your cleaned rhizomes in a dry, well-ventilated area that stays out of direct sunlight and away from freezing temperatures. A garage, a covered porch, or a basement work area is perfect. Spread them out in a single layer on a sheet of cardboard or newspaper. Do not stack them, as they need good airflow to dry properly.

Let the cannas cure for about 7 to 10 days. During this time, the remaining soil will dry up and become easy to brush off, and the cut ends of the stalks will begin to callus over. Once the rhizomes feel dry to the touch and the skin looks slightly matte, they are ready for their winter home.

Storing Your Cannas for Winter

The goal of winter storage is to keep the rhizomes dormant, cool, and just moist enough that they don't shrivel up, but dry enough that they don't rot. We often refer to this as the "Goldilocks" state of storage.

Choosing a Storage Container

There are several ways to house your cannas for the winter. The best method often depends on what supplies you have on hand:

• Cardboard Boxes: These are excellent because they allow for some breathability.
• Paper Bags: Good for smaller quantities or individual varieties.
• Plastic Totes (Lid Off): If you use plastic, leave the lid off or drill several large holes in the sides to ensure air can circulate. Never store rhizomes in a sealed plastic bag, as the trapped moisture will almost certainly lead to rot.

Using Storage Media

To maintain the right moisture balance, it is helpful to pack the rhizomes in a loose material. This material acts as insulation and helps regulate humidity. Common choices include:

• Peat Moss: This is a classic choice because it is sterile and holds a tiny bit of moisture without becoming soggy.
• Vermiculite or Perlite: These provide excellent aeration.
• Wood Shavings: Often sold as pet bedding, these work well and are very affordable.
• Newspaper: You can wrap individual rhizomes in sheets of dry newspaper.

Place a layer of your chosen material in the bottom of the box, lay the rhizomes on top (not touching each other if possible), and then cover them with more material.

Finding the Right Location

Your storage location should be dark and cool, but never freezing. The ideal temperature range is between 40°F and 50°F.

• Good spots: An unheated basement, a crawl space, or a cool closet.
• Spots to avoid: An attic (often too hot or too cold) or a garage that drops below freezing.

If the temperature is too warm, the cannas might try to start growing in the dark, which wastes their energy. If it is too cold, the cells inside the rhizome will freeze and turn to mush.

Winter Maintenance and Care

Digging up canna bulbs isn't quite a "set it and forget it" task. To ensure a high success rate, you should check on your stored rhizomes about once a month throughout the winter. This only takes a few minutes but can save your entire collection. For more season-long guidance, see How to Grow and Care for Canna Bulbs.

Open your boxes and feel a few of the rhizomes.

• If they feel shriveled or very light: They are getting too dry. Use a spray bottle to lightly mist the storage medium (the peat moss or shavings) with a little bit of water. You don't want it wet—just slightly damp to the touch.
• If you see fuzzy mold or soft spots: The environment is too damp. Remove any affected rhizomes immediately so the rot doesn't spread to the healthy ones. Leave the box open for a few days to let more moisture escape.

Most experienced gardeners are very happy if 80% to 90% of their rhizomes make it through the winter. By checking them monthly, you can catch small issues before they become big ones.

Dividing for More Blooms

One of the most exciting parts of digging up canna bulbs is seeing how much they have grown. A single rhizome planted in May can easily become a clump of five or more by October. You can divide these clumps either in the fall before you store them or in the spring before you plant them.

We generally recommend waiting until spring to do the final division. This way, you can see exactly where the new growth points (the "eyes") are located. However, if your clumps are simply too large to store, you can break them into smaller sections in the fall.

When dividing, make sure each piece has at least one or two "eyes"—these look like small, raised bumps or points on the surface of the rhizome. Use a clean, sharp knife to make the cuts. If you divide them in the fall, let the cut surfaces dry and callus for an extra day before putting them into storage.

Storing Potted Cannas

If you grow your cannas in large containers, the process is even easier. You don't necessarily have to dig the bulbs out of the soil. Once the frost has hit the foliage, cut the stalks down to the soil level just as you would in a garden bed. For containers, Short Cannas are a useful fit.

Move the entire pot into a cool, frost-free area like a basement or a deep garage. Stop watering the pot entirely. The soil will dry out, and the cannas will go dormant right there in the container. In the spring, you can bring the pot back out into the sun, give it a good soak, and wait for the new shoots to appear. Every few years, you will still need to empty the pot to divide the rhizomes, as they will eventually become "root-bound" and run out of space to grow.

Preparing for Spring

As the days get longer and the threat of frost passes, it will be time to wake up your cannas. About 4 to 6 weeks before the last expected frost in your area, you can bring your boxes out of storage.

At this stage, we recommend a final inspection. Discard anything that didn't make it through the winter. If you want a head start on the season, you can "pot up" your rhizomes indoors. Place them in containers with moist potting soil and keep them in a warm, sunny window. By the time the weather is warm enough to plant them outside, you will already have several inches of lush green growth. For depth details, see How Deep to Plant a Canna Bulb.

If you prefer to plant directly into the garden, wait until the soil has warmed up to at least 60°F. At Longfield Gardens, we have found that cannas are much happier when they go into warm soil rather than cold, damp earth. Planting too early can lead to slow growth or rot. For a bolder display next season, browse Tall Cannas.

Key Takeaway: Patience is a virtue when replanting. While it is tempting to get them in the ground at the first sign of spring, waiting for warm soil ensures the rhizomes "wake up" quickly and start growing vigorously.

Conclusion

Digging up canna bulbs is a simple and rewarding part of the gardening cycle. It marks the end of a successful summer and the beginning of a period of rest for both the gardener and the plants. By taking the time to harvest, cure, and store your rhizomes properly, you are preserving the vibrant beauty of your garden for years to come. If you're ordering more rhizomes, review our Shipping Information.

At Longfield Gardens, we believe that gardening should be an enjoyable journey. While it takes a little extra effort to overwinter tropical plants, the sight of those first bold leaves emerging in the spring makes it all worthwhile. Whether you are saving a single favorite variety or a whole collection of colors, the steps remain the same: wait for the frost, dig with care, dry them well, and keep them cool and dark. Our 100% Guarantee backs that up.

• Wait for the first frost to signal dormancy.
• Dig wide to avoid damaging the fleshy rhizomes.
• Cure the bulbs for a week to toughen the skin.
• Store in a cool, dark place in a breathable medium.
• Check monthly for moisture levels and health.

Managing your own canna collection is one of the easiest ways to see the "magic" of gardening as plants multiply and return year after year. With just a little bit of winter care, your tropical garden will be ready to shine again next summer.

FAQ

Can I dig up canna bulbs before the first frost?

Yes, you can dig them up earlier if you need to, especially if you are expecting a sudden deep freeze or if your schedule requires it. However, waiting for the first light frost is ideal because it signals the plant to move its energy into the rhizome for winter storage. If you dig them up while the leaves are still bright green and active, the rhizomes may be slightly smaller or less prepared for dormancy.

Should I wash the dirt off the rhizomes with water?

Rinsing the rhizomes is a matter of personal preference. Some gardeners find it helpful because it allows them to see the "eyes" and check for pests or rot more clearly. If you do use water, it is essential that you allow the rhizomes to dry completely (cure) for about 7 to 10 days before putting them into storage. Storing wet rhizomes in a box will almost always result in mold or rot.

What is the best material to pack canna bulbs in for storage?

The most popular materials are peat moss, wood shavings (like those used for small animal bedding), or vermiculite. These materials are excellent because they are lightweight, sterile, and provide good insulation. They also help to absorb any excess moisture while preventing the rhizomes from drying out completely. Plain, dry newspaper is also a great budget-friendly alternative for wrapping individual bulbs.

What should I do if my stored cannas start growing in February?

If you notice new green shoots appearing while the plants are still in storage, it usually means the storage area is a bit too warm or receiving some light. If the shoots are small, you can try to move the box to a slightly cooler (but still frost-free) location to slow them down. If the shoots are already several inches long, you might want to "pot them up" in containers and treat them as houseplants until it is warm enough to move them outside.