Introduction
Canna lilies are the undisputed stars of the summer garden, offering bold foliage and vibrant blooms that make any backyard feel like a tropical getaway. At Longfield Gardens, we love how these high-energy plants transform a landscape with their height and drama. While cannas are tropical by nature, you don't have to treat them as annuals. With a little bit of care at the end of the season, you can save these beautiful plants and enjoy them again next year.
This guide is designed for home gardeners who want to keep their favorite canna varieties flourishing year after year. We will walk you through the simple process of lifting, cleaning, and storing your canna rhizomes through the cold winter months. By following these steps, you can expand your garden collection without having to start from scratch every spring. Learning how to protect your plants from the frost is a rewarding skill that ensures your garden returns even bigger and better each season.
Why Overwintering Cannas Is Worth the Effort
Cannas grow from thick, fleshy underground stems called rhizomes. In their native tropical environments, these rhizomes stay in the ground year-round. However, in most parts of the United States, winter temperatures drop low enough to freeze the soil, which would turn a tender canna rhizome into mush. By bringing them indoors, you are essentially giving them a safe place to nap until the warm weather returns.
One of the best reasons to overwinter your cannas is that they actually get better with age. As a canna grows throughout the summer, the rhizome expands and produces "eyes," which are the buds that will become next year's stalks. When you store them successfully, you often end up with more plants than you started with because you can divide the large clumps in the spring. It is a cost-effective and satisfying way to fill your garden beds with lush, tropical color.
Identifying Your Hardiness Zone
Before you start digging, it is helpful to know your USDA hardiness zone. This helps you determine if overwintering is a choice or a necessity. We ship our plants based on these zones to ensure they arrive at the perfect planting time for your local climate.
For gardeners in zones 8 through 11, canna lilies are often hardy enough to stay in the ground all year. In these warmer regions, a thick layer of mulch is usually all that is needed to protect the rhizomes from an occasional light frost. However, if you live in zone 7 or colder, the ground will likely freeze deep enough to damage the plant. In these areas, lifting the rhizomes is the best way to guarantee they survive until spring.
Key Takeaway Most gardeners in the United States will need to lift their cannas once the temperatures drop. If your area experiences regular freezing temperatures that penetrate the soil, your cannas will need a cozy spot indoors for the winter.
When to Begin the Overwintering Process
Timing is everything when it comes to preparing your cannas for storage. 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 the soil freezes solid.
The ideal signal to start is the first light frost of autumn. You will notice the lush green or burgundy leaves turn black or brown after a cold night. This might look a bit sad at first, but it is actually a helpful part of the process. The frost tells the plant that the growing season is over and it is time to move into dormancy. Once the foliage has been nipped by frost, you should aim to have your cannas dug up and tucked away within a week or two.
If you live in a region where frost comes very late, you can still lift your cannas in late October or early November. Even if the leaves are still green, the shorter days and cooler soil temperatures will have slowed the plant's growth enough for a successful transition into storage.
Preparing the Plants for Digging
Before you reach for your shovel, you need to clear away the top growth. This makes the lifting process much cleaner and easier to manage.
Using a pair of sharp, clean garden shears or a lopper, cut the canna stalks down to about four to six inches above the soil line. Leaving a small "handle" of the stalk is very helpful. It gives you something to hold onto while you are moving the clumps and helps you identify which side of the rhizome is "up" when it comes time to replant in the spring.
Once the stalks are cut, clear away any fallen leaves or garden debris from around the base of the plants. This helps prevent pests or fungal spores from hitching a ride into your storage containers.
Tools for the Job
- A sturdy garden fork or spade
- Sharp pruning shears
- A garden hose with a spray nozzle
- Garden gloves
- Containers for storage (cardboard boxes or plastic bins)
- Storage medium (peat moss, perlite, or wood shavings)
Lifting Canna Rhizomes Safely
Canna rhizomes can grow surprisingly large and heavy over a single summer. They often spread out horizontally just beneath the soil surface. To avoid damaging the fleshy roots, you need to be careful with your digging technique.
Start by inserting your garden fork or spade about a foot away from the base of the stems. If you dig too close, you risk slicing through the rhizome. Work your way around the entire clump, gently prying upward to loosen the soil. You want to lift the entire mass as one piece if possible.
Once the soil is loose, use the stalks as a handle to gently lift the clump out of the ground. Don't worry if the clump is heavy with soil; we will address that in the next step. If a piece of the rhizome breaks off during the process, don't throw it away! As long as it has at least one "eye" or growing point, it can grow into a new plant next year.
Cleaning and Curing
Once the cannas are out of the ground, they need a bit of grooming before they go into storage. First, shake off as much loose soil as you can. If your soil is heavy clay, you might need to use a garden hose to gently wash the dirt away. Getting the rhizomes clean makes it much easier to inspect them for any signs of damage or rot.
After cleaning, the rhizomes need a "curing" period. This is a short drying phase that allows the outer skin to toughen up slightly, which helps prevent rot during the winter. Place the clumps in a dry, frost-free area out of direct sunlight. A garage, shed, or covered porch works well. Let them sit for one to two days until the surface feels dry to the touch. Avoid leaving them out for too long, as you don't want the fleshy interior to shrivel or dry out completely.
What to Do Next
- Cut stalks to 4-6 inches.
- Loosen soil 12 inches away from the plant.
- Lift the clump gently and shake off excess dirt.
- Let the rhizomes air dry in a protected spot for 24–48 hours.
Choosing Your Storage Medium
The goal of winter storage is to keep the rhizomes dormant, cool, and just slightly moist. If they are too wet, they will rot. If they are bone-dry, they will shrivel up and die. Using a storage medium helps regulate this moisture balance.
There are several great options for packing your cannas:
- Peat Moss: This is a classic choice because it holds just enough moisture while still allowing for some airflow.
- Vermiculite or Perlite: These lightweight minerals are excellent for maintaining a stable environment.
- Wood Shavings: Often sold as pet bedding, these are inexpensive and provide good insulation.
- Shredded Newspaper: A great "recycled" option that is easy to find around the house.
At Longfield Gardens, we find that slightly dampened peat moss or wood shavings offer the most consistent results for home gardeners.
Selecting a Storage Container
The container you choose should allow for a small amount of air exchange. You want to avoid airtight plastic bags or sealed bins, as these trap moisture and almost always lead to mold and rot.
Cardboard boxes are an excellent choice because the material "breathes" naturally. You can also use plastic storage bins, but you should leave the lids off or drill several large holes in the sides to ensure the plants don't suffocate. Paper grocery bags can also work for smaller rhizomes, though they are less sturdy if you have large, heavy clumps.
Packing the Rhizomes for Winter
Now it’s time to tuck your cannas in for their winter nap. Start by placing a two-inch layer of your chosen storage medium in the bottom of your container.
Arrange the canna clumps on top of the medium. Try to keep them in a single layer if you can. It is best if the rhizomes aren't touching each other; this way, if one piece happens to develop a spot of rot, it won't easily spread to its neighbors. Cover the rhizomes with more peat moss or shavings until they are completely buried. If you have a lot of plants, you can add another layer of medium and a second layer of rhizomes.
Finally, label your boxes! It is easy to forget which box contains the "Red King Humbert" and which has the "City of Portland" by the time spring rolls around. Write the variety name and the date on the outside of the box with a permanent marker.
Finding the Perfect Storage Location
Where you put your boxes is just as important as how you pack them. Cannas need a spot that is cool and dark, but strictly frost-free.
The ideal temperature range is between 45°F and 55°F. If the location is too warm (above 60°F), the plants may try to start growing in the dark, which exhausts their energy. If the location is too cold (below 40°F), you risk the rhizomes freezing.
Good storage locations include:
- An unheated basement
- A crawl space
- An insulated garage that stays above freezing
- A cool closet in a mudroom
Keep the boxes off the floor if possible, especially if you are storing them on a concrete garage or basement floor, as concrete can draw out moisture and become very cold. Placing the boxes on a wooden pallet or a shelf is a simple way to provide a bit of extra insulation.
Winter Maintenance and Monitoring
Overwintering isn't a "set it and forget it" task. To ensure the highest success rate, we recommend checking on your rhizomes about once a month throughout the winter.
Open the boxes and feel the rhizomes. They should feel firm, like a fresh potato. If you notice any soft, mushy spots, use a clean knife to cut that section away and discard it. If the storage medium feels bone-dry and the rhizomes are starting to look wrinkled or shrivelled, use a spray bottle to lightly mist the packing material. You don't want it to be wet—just a tiny bit of humidity is enough to keep them plump.
If you see any fuzzy white mold starting to grow on the surface, it’s a sign that the storage environment is too damp or doesn't have enough airflow. Move the box to a slightly drier location and leave the top open for a few days to let the excess moisture escape.
Key Takeaway A quick monthly check is the best way to prevent small issues from becoming big problems. Catching a single soft spot early can save an entire box of plants.
Waking Up Your Cannas in the Spring
When the days begin to lengthen and the threat of a hard frost has passed, it is time to think about bringing your cannas back into the light. This usually happens in late March or April, depending on your local climate.
You have two choices for starting your cannas in the spring. You can plant them directly into the garden once the soil has warmed to at least 60°F and all danger of frost is gone. This is the easiest method, though it may take a few weeks for the first sprouts to appear above the soil.
Alternatively, you can "pre-start" your cannas indoors to get a head start on the season. This is a great trick if you live in a northern climate with a short growing season. About 4 to 6 weeks before the last expected frost, plant the rhizomes in pots with some potting soil. Place the pots in a warm, sunny window or under grow lights. By the time it is warm enough to plant them outside, you will already have established plants with several inches of growth, leading to earlier blooms in the summer.
Dividing Rhizomes for More Plants
Spring is also the perfect time to divide your canna clumps. When you pull them out of storage, you will see the individual "segments" of the rhizomes. Each segment with a visible "eye" or bud can become a new plant.
Using a clean, sharp knife, cut the large clumps into smaller sections. Make sure each piece has at least one healthy-looking bud, though two or three eyes per piece will give you a stronger plant in the first year. Let the cut ends dry for a few hours to form a callous before planting. This simple step is how one or two cannas can eventually fill an entire garden border over a few seasons.
Safety and Best Practices
While gardening is a safe and joyful activity, it is always wise to keep a few things in mind. Canna lily rhizomes are generally not considered toxic to humans or pets, but it is always a good practice to keep stored bulbs and rhizomes out of reach of curious dogs or small children. Ingesting any garden plant can cause mild stomach upset.
Always wear gloves when handling soil or packing materials like peat moss to protect your skin. If you use any tools to cut away rot, remember to clean them with a quick wipe of rubbing alcohol before moving on to the next plant. This prevents the spread of any potential issues between your rhizomes.
Common Myths About Canna Storage
There are plenty of "garden hacks" online about overwintering plants, but sticking to the basics is usually the most reliable path. For example, some suggest storing cannas in a refrigerator. While the temperature is okay, refrigerators are often too dry and can cause the rhizomes to shrivel. Others suggest leaving them in their outdoor pots and just bringing the pots inside. This can work if the soil is allowed to dry out completely, but the rhizomes are more prone to rot in old, compacted potting soil than they are in fresh peat moss or shavings.
Another common misconception is that you must wait for the foliage to die back completely on its own. While you can do this, waiting too long increases the risk of a deep freeze damaging the rhizomes. The "first frost" rule is the most reliable guide for most US gardeners.
Conclusion
Successfully overwintering your canna lilies is a simple way to bring a sense of continuity and abundance to your garden. By taking the time to lift and store these tropical beauties, you are investing in a more vibrant landscape for the years to come. It turns a one-season plant into a lifelong garden companion.
At Longfield Gardens, we take pride in providing high-quality plants that are ready to perform. We stand behind our quality with a 100% guarantee: our items are true to variety and arrive in prime condition. If you ever have a concern about the quality of your delivery, please reach out to us promptly so we can help. We want your gardening experience to be as rewarding and successful as possible.
- Wait for the first frost to signal dormancy.
- Store in a cool, dark, frost-free location (45–55°F).
- Use a breathable storage medium like peat moss or wood shavings.
- Check monthly for moisture and health.
We are here to help you grow a more beautiful world, one bulb at a time. Whether you are a beginner or a seasoned pro, the cycle of planting, growing, and preserving is what makes gardening such a wonderful journey.
FAQ
Can I leave my canna lilies in the ground if I live in Zone 7?
In zone 7, cannas can sometimes survive the winter in the ground, especially if they are planted in a protected "microclimate" near a south-facing wall. However, success depends heavily on the severity of the winter. For the best results, we recommend applying a very thick layer (6–8 inches) of mulch or lifting a few "backup" rhizomes just to be safe. For more guidance, see this guide to leaving canna bulbs in the ground over winter.
How do I know if a stored canna rhizome is dead?
A healthy rhizome should feel firm and heavy for its size. If a rhizome feels very light, hollow, or shrivelled like a prune, it has likely dried out too much and may not grow. Similarly, if it is soft, mushy, or has a foul odor, it has succumbed to rot and should be discarded to protect the other plants.
Do I need to wash the dirt off the rhizomes before storing them?
While it isn't strictly mandatory, washing the dirt off makes it much easier to see the health of the rhizome and identify the "eyes" for dividing. If you do wash them, just ensure they are given enough time to dry (cure) for a day or two before you pack them away in your storage medium.
My cannas are in large pots; do I still need to dig them up?
If you live in a cold climate, the soil in pots freezes much faster than the soil in the ground. You can either dig the rhizomes out of the pots and store them as described above, or you can cut the stalks back and bring the entire pot into a frost-free garage or basement. If you store the whole pot, do not water it at all during the winter; the soil must remain dry to keep the plant dormant. See this guide to overwintering potted cannas.
