As a passionate gardener I adore the vibrant colors and tropical flair that cannas bring to my garden beds each summer. Their large, banana-like leaves and stunning blooms create an exotic oasis right in my own backyard.
While cannas thrive in warm weather their beautiful foliage dies back and goes dormant when cool fall temperatures arrive. But with proper overwintering care you can save cannas to replant again next spring.
Overwintering cannas allows you to:
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Save money by not having to repurchase new bulbs every year.
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Build your collection by saving and dividing rhizomes.
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Share extras with gardening friends,
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Enjoy consistent blooms as mature rhizomes produce more flowers.
Overwintering sounds complicated but it’s surprisingly easy with a few simple steps. In this guide, I’ll walk through exactly when and how to dig up cannas, proper storage conditions, what to look for come spring, and when to replant.
When to Dig Up Cannas for Overwintering
Cannas form thick underground rhizomes that are the key to overwintering success. But you need to dig them up at just the right time.
Ideally, let your cannas experience a light frost or two before digging them up. This usually occurs in mid to late fall. Waiting for some frost damage:
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Allows the rhizomes to go dormant before storage.
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Maximizes the growing season before digging too early.
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Prevents leaving rhizomes in the ground too long where they may rot.
Signs cannas are ready for digging include:
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Leaves and stems blackened by frost.
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Plants appearing dried out and faded.
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Nighttime temperatures dipping below freezing.
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1-2 light frosts have occurred in your area.
I like to dig up my cannas within 1-2 weeks of heavy frost damage. This prevents the rhizomes from rotting but also ensures I dig before a hard freeze sets in.
How to Dig and Store Rhizomes for Overwintering
Digging up and storing the rhizomes properly is key for successfully overwintering cannas. Follow these steps when harvesting in fall:
1. Cut Back Foliage
Trim dead or fading leaves back to about 2 inches above soil level. This makes it easier to access the rhizomes underground.
2. Dig Under Clumps
Use a spade or digging fork to gently lift up entire rhizome clumps. Cannas have shallow roots so they pull up easily.
3. Gently Rinse
Rinse off excess soil but don’t damage the roots. Dry the clumps for 2-3 days in a shaded spot to cure.
4. Break Apart & Inspect
Carefully separate the rhizome mass into smaller sections. Discard any diseased or damaged rhizomes.
5. Allow Divisions to Cure
Let rhizome divisions cure for 2-3 more days before storage. This helps wounds callous over.
6. Store in Cool Spot
Place cured rhizomes in peat moss or damp sand. Use boxes or breathable bags.
Best Storage Conditions for Overwintering
To keep your stored rhizomes healthy, you need to provide proper storage conditions all winter long. Follow these guidelines:
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Ideal Temperature: Between 40-50°F. Avoid freezing or hot temps.
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Humidity: Keep rhizomes slightly moist but not wet.
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Light: Store in complete darkness to prevent sprouting.
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Ventilation: Use breathable containers for air circulation.
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Location: Unheated garage, cellar, crawl space, or basement.
Monitor your storage spot occasionally throughout winter. Watch for any sprouting, rotting, or desiccation issues. Make adjustments as needed to maintain ideal conditions.
What to Look for When Replanting in Spring
As spring approaches, check stored rhizomes for any signs of problems. Healthy rhizomes should be:
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Firm, turgid, and heavy.
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Free of mold, rot, or hollowness.
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Showing plump growth buds or “eyes”.
Discard any rhizomes that are soft, mushy, or extremely lightweight as they likely died over winter. Also remove any sprouted sections that may have exhausted energy reserves.
Once you’ve culled damaged rhizomes, soak the healthy ones for a few hours before planting to rehydrate.
When to Replant Cannas Outdoors
Cannas can be replanted once all danger of frost has passed and soil temperatures warm up. Some guidelines for replanting:
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Evening temps consistently above 55°F.
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2-3 weeks after your region’s average last spring frost date.
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When other heat-loving plants like dahlias are being planted.
Prepare garden beds with rich, moist soil. Plant rhizomes 3-4 inches deep, 12 inches apart with the eyes pointing up. Water thoroughly after planting and provide 1-2 inches of water per week. Fertilize lightly once new shoots appear.
Enjoy Lush Cannas Year After Year
While cannas thrive in hot weather, gardeners in cool climates can easily overwinter their rhizomes indoors. Storing them properly each fall allows you to enjoy lush tropical foliage and flowers season after season.
Just be sure to time it right in the fall, provide proper storage conditions, and replant again once danger of frost has passed. With a little TLC, your cannas will thank you with abundant growth and vivid blooms summer after summer.
Why Should I Overwinter Cannas?
Cannas spread vigorously, forming clumps of thick, fleshy rhizomes held close to the soil surface. That’s a lot of plant material to simply throw away when temperatures hit the freezing mark! Especially when they are easy to dig, easier to store, and doing so over the winter months allows you to cost-effectively increase their presence in your garden. You can build your cultivar collection over time and still have plenty to share with other gardeners.
You don’t need a greenhouse to consider overwintering Cannas. In fact, even if you do have a greenhouse, it’s much easier to store them in a garage, basement, crawl space, or unheated spare room. Don’t have any of those places? You might have a friend who doesn’t mind housing a plastic bag of maintenance-free rhizomes in their cellar – particularly when you share a few in the spring!
Using an unheated cold frame in the early spring months can help you get the foliage going earlier in the season, but even if you don’t, you’ll find your Cannas can’t wait to get started again once the temperatures warm.
Natural Timing For Canna Rhizomes
Keep your storage areas cool, and when all danger of frost has past, re-plant outside or in containers in rich soil with a small amount of balanced fertilizer. Foliage will take a while to re-sprout, but will be ready for your summer garden. If you are planting in a water feature, make sure to cover the soil of the container with at least 2 inches of pea gravel to keep soil firmly in the pot.
CANNA LILY Overwintering – How to Store Bulbs (Rhizomes) over Winter
FAQ
How do you winterize cannas?
The roots will be dormant and won’t require water, but should be protected from complete desiccation. Check the stored roots during the winter and add a little moisture to the peat moss if the roots begin to shrink or shrivel up. You can store canna in a garage or cool, dark basement.
Can you keep cannas in pots over winter?
Where Do I Store Cannas For Overwintering? Find a cool, dark space that stays above freezing but below 55 throughout the winter. Non-fluctuating temperatures are best as they prevent early sprouting.
Can a Canna overwinter?
Overwintering cannas in pots is another possibility if you have the space. Most of the time, the extra soil takes up quite a bit of room, but if you only have a few cannas to overwinter, you can try storing the pot in the basement as well. Try these tips: Cut back the foliage as you would at the end of the season.
Should you overwinter Canna bulbs?
Even those who grow cannas in the ground can benefit from overwintering them in pots. As a result, those in most US regions will have to decide whether they’d rather uproot and overwinter the bulbs indoors or grow them as annuals instead. If you already grow your cannas in containers, congratulations! – this decision won’t affect you.
Can Canna bulbs be left in the ground over winter?
In warm climates (USDA hardiness zones 8 to 10), canna bulbs can be left in the ground over winter, and the plants perform reliably as perennials, coming back year after year. However, north of zone 8, the bulbs will die if they spend winter in the ground.
How do you overwinter canna lilies?
By far the most popular method of overwintering canna lilies is to dig up and store the bulbs. This is a must if they are planted in the garden. The nice thing about it is that there’s no rush to dig them up. You can leave them in the ground even after a hard freeze kills the plant.
How do you overwinter a Canna plant?
Follow this checklist for successfully overwintering your cannas: Dig up rhizomes in early fall after foliage is killed by frost. Shake off excess soil and divide large clumps into smaller sections. Allow divisions to cure for 2-3 days in a warm, dry spot before storing. Pack in slightly moist peat moss or vermiculite.
Can a Canna grow in winter?
In very cold climates, cannas can be grown as annuals. Plant rhizomes in spring after frost danger has passed. Dig up the rhizomes in fall to overwinter or simply discard them after first frost and replant new ones next year.