Introduction
There is something incredibly satisfying about the bold, tropical flair that canna lilies bring to a summer garden. These canna lilies have oversized leaves and brilliant blooms. At Longfield Gardens, we know it can be hard to say goodbye to these beauties when the temperatures dip.
You do not have to start from scratch every spring. By taking simple steps to protect the rhizomes, you can save your favorite varieties and watch them grow even larger and more impressive each summer. This guide explains exactly how to manage canna lily bulbs for winter storage so they survive and return next season. Whether you are a beginner or an experienced gardener, you can successfully preserve your plants with a little bit of space in a cool closet or basement.
Quick Summary:
- Wait for frost: Let the foliage blacken after the first frost to trigger dormancy.
- Dig and cure: Carefully lift the rhizomes and let them air-dry for about a week to toughen the skin.
- Pack breathable: Store in boxes with peat moss, wood shavings, or newspaper to regulate moisture.
- Store cool: Keep containers in a dark spot between 40°F and 50°F.
- Monitor: Check the rhizomes monthly for rot or shriveling until spring replanting.
Why Storing Canna Lily Bulbs Is Worth the Effort
Cannas are remarkably resilient and vigorous plants. While they are technically tropical, they are surprisingly easy to keep "asleep" during the cold months. Saving your rhizomes—which are the thick, potato-like roots often referred to as bulbs—is not just about saving money. It is about continuity in your garden design.
When you store cannas, you are keeping a plant that has already adapted to your garden's soil and light conditions. Furthermore, canna rhizomes naturally multiply. A single plant put into the ground in May can turn into a large clump by October. By digging and storing them, you give yourself the opportunity to divide those clumps in the spring to expand your garden or share with friends.
Understanding Your Climate and Hardiness Zones
Before you grab your shovel, check if you actually need to dig your cannas. Canna lilies are hardy in USDA zones 8 through 10. In these warm regions, the ground does not freeze deeply enough to harm the rhizomes; you can simply cut the foliage back and leave them in the ground.
However, for gardeners in zones 3 through 7, the winter cold is too intense for these tropical plants to survive outdoors. In zone 7, some gardeners have success leaving cannas in the ground with a heavy layer of mulch. But for the most reliable results, digging them up is the best way to ensure they return next year.
Key Takeaway: If you live in USDA zone 7 or colder, digging and storing your canna rhizomes is the most reliable way to ensure they survive the winter and bloom again next year.
When to Dig Your Canna Lily Bulbs
Timing is everything. You want to give the plants as much time as possible to store energy, but you must get them out of the ground before the soil freezes hard.
The best signal to start the process is the first light frost of autumn. You will notice the lush green or bronze leaves suddenly turn black or brown. This "first light frost" tells the plant to stop sending energy to the leaves and move all nutrients down into the rhizomes for winter dormancy.
If you live in an area where frost comes very late, wait until the foliage begins to yellow naturally in late autumn. Aim to dig them up when the soil is still workable and relatively dry.
Tools You Will Need for the Job
You likely already have these items in your garden shed:
- A sturdy garden fork or spade.
- Garden shears or a sharp knife.
- A garden hose with a spray nozzle.
- Storage containers (cardboard boxes, plastic bins, or paper bags).
- Packing material (peat moss, vermiculite, perlite, or newspaper).
- A permanent marker for labeling.
How to Dig Canna Rhizomes Without Damage
The goal during harvest is to lift the rhizome clumps out of the earth with as little physical stress as possible. Canna rhizomes are fleshy and can be bruised or cut if hit directly with a shovel.
- Cut Back the Foliage: Trim the stalks down to about 4 to 6 inches above the soil line. This acts as a convenient "handle" for lifting and helps you identify which way is up.
- Loosen the Soil: Using your garden fork, dig a circle around the base of the plant, staying about 6 to 10 inches away from the main stems. Push the fork deep and gently pry upward.
- Lift the Clump: Use your fork to lift the entire root mass out of the ground. Shake the clump gently to remove large chunks of loose soil.
- Initial Inspection: Check for any sliced or damaged rhizomes. Set damaged pieces aside to dry separately so they don't introduce rot to the healthy ones.
What to do next:
- Clear a space in a garage or shed where you can work out of the direct wind.
- Gather your labels and markers so you don't forget which color is which.
- Prepare a flat surface for the "curing" phase.
Cleaning and Curing: The Secret to Success
Many gardeners make the mistake of taking cannas straight from the garden to a sealed box, which leads to mold. The most important step is "curing"—letting the outer skin of the rhizome dry out and toughen up.
Cleaning the Rhizomes
- Dry Brushing: If your soil is sandy and dry, let the clumps sit for a few hours and then brush off the excess dirt with your hands.
- Washing: If your soil is heavy clay or very wet, use a garden hose to gently wash the soil away. Avoid a high-pressure blast to keep the skin intact.
The Curing Process
Place cleaned rhizomes in a single layer on a tray or cardboard in a well-ventilated area out of direct sunlight. Let them sit for about 7 to 10 days. During this time, the cut ends will dry out, creating a natural defense against fungal issues.
Choosing the Right Storage Medium
Once cured, cannas need to stay dormant—not so wet that they rot, but not so dry that they shrivel.
- Peat Moss: Holds a tiny bit of moisture while staying airy.
- Vermiculite or Perlite: Sterile and provides great aeration.
- Wood Shavings or Sawdust: Use untreated shavings, like the kind for pet bedding.
- Newspaper: You can wrap individual rhizomes in several layers of dry newspaper.
Setting Up Your Storage Containers
Use containers that allow for air exchange. Avoid airtight plastic tubs.
- Cardboard Boxes: These are ideal because the material "breathes."
- Plastic Bins with Holes: Drill several half-inch holes in the sides and leave the lid slightly ajar.
- Paper Bags: These work well for smaller quantities.
To pack them, place a 2-inch layer of your chosen medium at the bottom. Lay the rhizomes on top, ensuring they aren't squeezed too tightly. Cover them with more medium until they are tucked in.
"The best storage environment is like a good wine cellar: cool, dark, and slightly humid, but never freezing."
Finding the Perfect Storage Location
Where you put your boxes matters. Aim for a temperature range between 40°F and 50°F.
- Basements: Unheated or cool basements are usually the best option.
- Crawl Spaces: These often maintain a consistent, cool temperature.
- Attached Garages: Ensure the temperature does not drop below freezing during a cold snap.
- Root Cellars: The gold standard for storage if available.
Avoid storing near a furnace or in heated living spaces. If temperatures stay above 60°F, rhizomes may begin to sprout prematurely.
Winter Check-Ups: Don't Set It and Forget It
A quick monthly check-up can save your entire collection.
- If they feel mushy or smell bad: This is rot. Immediately discard affected pieces.
- If they look extremely shriveled: Use a spray bottle to lightly mist the packing medium. It should be slightly damp to the touch, not wet.
- If you see sprouts: Move the box to a cooler spot to keep the plants dormant.
Special Case: Storing Cannas Grown in Containers
If you grow your cannas in large pots, you can move the entire pot—soil and all—into a cool, dark location once the foliage is cut back.
The soil acts as the storage medium. Do not water the pot over the winter. In the spring, bring the pot out and give it fresh compost and water. After two or three years, you will need to tip the pot and divide the rhizomes to prevent overcrowding.
Preparing for Spring Replanting
About 4 to 6 weeks before your last expected frost date, bring the boxes out of storage. Look for small "eyes" beginning to swell or turn pinkish-white. This is the perfect time to divide large clumps; each piece should have at least one or two healthy "eyes."
To jump-start the season, you can plant the rhizomes in pots indoors. Move them outside once the weather is consistently warm, usually in late May.
Common Mistakes to Avoid
- Digging too early: Wait for the first light frost or yellowing leaves to ensure the plant has enough stored energy.
- Storing while wet: Ensure rhizomes are dry to the touch to prevent "winter rot."
- Freezing temperatures: A single night of freezing can turn healthy rhizomes into mush.
- Forgetting labels: Always label clearly, as different varieties like City of Portland look identical as dormant tubers.
Summary of the Canna Storage Process
Follow this simple workflow for autumn cleanup:
- Wait for Frost: Let the foliage turn black.
- Cut and Dig: Trim stalks to 6 inches and lift gently.
- Cure: Air-dry for about one week in a protected area.
- Pack: Use breathable boxes with peat moss or newspaper.
- Store: Maintain a cool temperature between 40°F and 50°F.
- Check Monthly: Remove rot or mist if shriveled.
Key Takeaway: Success with cannas depends more on moisture control and temperature than on any specific "trick." Keep them cool, keep them dark, and keep them just dry enough.
Conclusion
Storing canna lily bulbs for winter transforms a seasonal plant into a perennial companion that grows more beautiful with each passing year. While the process requires a few steps, the payoff of seeing those first green shoots emerge in the spring—knowing they came from your own hard work—is well worth the effort.
At Longfield Gardens, we are dedicated to helping you succeed with every bulb and rhizome you plant. Ready to plan for next year? Browse our selection of canna lilies and other summer-blooming bulbs to find the perfect companions for your overwintered favorites.
FAQ
When is the best time to dig up my canna lily bulbs?
You should wait until the first light frost kills or blackens the foliage. This signal tells the plant to go dormant and move its energy into the rhizomes. If you live in an area without frost, wait until late autumn when the leaves naturally begin to yellow and die back.
Do I need to wash the dirt off the rhizomes before storing them?
It depends on your soil. If your soil is dry and sandy, you can simply brush off the excess dirt. If it is wet or heavy clay, it is better to gently wash the rhizomes with a hose to prevent soil-borne diseases from being trapped in the storage container, but make sure they dry completely afterward.
What is the ideal temperature for storing canna bulbs over the winter?
The ideal temperature range is between 40°F and 50°F. This is cold enough to keep the plants dormant but warm enough to prevent the rhizomes from freezing. Basements, crawl spaces, and insulated garages are usually the best locations for maintaining this temperature.
Can I store my cannas in the same pots they grew in?
Yes, you can store container-grown cannas in their original pots. Cut the foliage back after the first frost and move the entire pot to a cool, dark, frost-free location. Do not water the pot during the winter; simply wait until spring to bring it back out and resume watering once the weather warms.
