Table of Contents
- Introduction
- Understanding Canna Rhizomes
- To Wash or Not to Wash?
- When to Start the Process
- How to Properly Wash Canna Rhizomes
- The Most Important Step: Curing
- Evaluating Rhizome Health
- Choosing Your Storage Medium
- Finding the Perfect Storage Spot
- Winter Maintenance: The Monthly Check-In
- Preparing for Spring
- Summary of the Canna Storage Process
- FAQ
Introduction
There is nothing quite like the tropical flair that cannas bring to a summer garden. Their oversized, paddle-like leaves and vibrant, torch-like flowers create a lush atmosphere that makes any backyard feel like a private getaway. At Longfield Gardens, we love how these easy-to-grow plants transform a landscape in just one season. As the cooler autumn air arrives, many gardeners look forward to the rewarding task of "lifting" and saving these beautiful plants for next year.
The question of whether you should wash canna bulbs—technically known as rhizomes—before storing them is one of the most common topics we hear about during the fall cleanup. Some gardeners prefer a pristine, clean start, while others swear by leaving a little garden soil on the roots. This guide will walk you through the benefits of each method so you can choose the best approach for your specific garden conditions and storage space.
We will cover the step-by-step process of digging, cleaning, and curing your cannas to ensure they stay healthy all winter long. Whether you are a first-time canna grower or a seasoned pro, these simple techniques will help you protect your investment and enjoy even bigger blooms next summer. If you want to shop a ready-made mix, the Canna Assorted Collection is a great place to start. The key to success lies in how you handle the transition from the garden bed to the storage bin.
Understanding Canna Rhizomes
Before we dive into the cleaning process, it helps to understand what you are actually digging up. While most people call them "bulbs," cannas grow from rhizomes. A rhizome is a thick, fleshy underground stem that stores energy for the plant. If you look closely at a canna rhizome, you will see "eyes" or small bumps. These are the growth points where next year’s stems and leaves will emerge.
Because these rhizomes are fleshy and full of moisture, they are sensitive to freezing temperatures. In USDA zones 8 and warmer, cannas can often stay in the ground year-round with a layer of mulch. If you are unsure of your region, the Hardiness Zone Map can help you check your zone. However, in zones 7 and colder, the ground can freeze deep enough to damage the rhizomes. This is why we lift them in the fall.
The goal of winter storage is to keep the rhizome in a state of "suspended animation." You want it to stay cool enough that it doesn’t sprout, but warm enough that it doesn’t freeze. You also need to keep it just hydrated enough so it doesn’t shrivel into a raisin, but dry enough that it doesn't rot. Choosing whether to wash or shake off the soil is the first step in finding that perfect balance.
To Wash or Not to Wash?
The short answer is that you can do either, but your choice should depend on your soil type and your storage environment. Both washing and "dry cleaning" have distinct benefits.
The Case for Washing
Washing your canna rhizomes with a garden hose is a popular choice for several reasons. First, it makes the rhizomes much cleaner to handle. If you plan to store your cannas in a finished basement or a utility closet, you likely don't want garden dirt crumbling onto your floors all winter.
More importantly, washing allows you to inspect the health of the rhizomes. Once the mud is gone, you can easily see the "eyes" and check for any signs of soft spots, mold, or pests. If you have heavy clay soil, washing is often the only way to remove the thick, sticky clumps that can trap too much moisture against the rhizome during storage.
The Case for Shaking (Dry Cleaning)
Many experienced gardeners prefer to simply shake off the excess soil and leave the rest. This is often referred to as "dry cleaning." A small amount of soil clinging to the rhizome can act as a natural protective buffer. This soil helps retain a tiny bit of moisture, preventing the rhizome from drying out too quickly if your storage area is very dry.
If you have sandy or loose loamy soil, the dirt usually falls away easily on its own. In these cases, washing might be an unnecessary extra step that introduces unwanted moisture into the "curing" process.
Key Takeaway Wash your rhizomes if you have heavy clay soil or want to inspect for pests. Stick to shaking off the soil if you have sandy soil or a very dry storage area where the extra protection is helpful.
When to Start the Process
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. The best time to dig them up is right after the first "blackening frost." This is a light frost that turns the foliage brown or black but doesn't freeze the ground.
Once the leaves have been hit by frost, the plant receives a signal to go dormant. At this point, the stems are no longer sending energy to the leaves, and the rhizomes are ready for their winter nap. It is best to wait for this frost, but if your local forecast predicts a deep, hard freeze (where the ground itself might freeze), you should go ahead and dig them even if the foliage is still green.
Step-by-Step Digging
- Cut the stalks: Use a pair of clean garden shears to cut the canna stems down to about 3 or 4 inches above the soil line. This "handle" makes the rhizomes easier to move.
- Loosen the soil: Use a garden fork rather than a shovel if possible. Start digging about 12 inches away from the base of the plant. Canna rhizomes can spread quite far, and you want to avoid slicing through them.
- Lift gently: Rock the fork back and forth to loosen the root ball. Once the soil is loose, lift the entire clump out of the ground.
- Initial shake: Give the clump a gentle shake to remove the largest chunks of soil.
How to Properly Wash Canna Rhizomes
If you have decided that washing is the right move for your garden, follow these steps to do it safely. The goal is to get them clean without damaging the delicate skin or "eyes."
Use a Gentle Spray
Take your clumps to a lawn area or a gravel driveway where the runoff won't cause a muddy mess. Use a garden hose with a spray nozzle set to a medium, gentle setting. Avoid using a high-pressure "jet" setting, as this can tear the skin of the rhizome. Damaged skin creates an entry point for bacteria and fungi during the winter.
Focus on the Crevices
Canna rhizomes grow in a segmented, bumpy pattern. Dirt loves to hide in the nooks and crannies between these segments. Spend a little extra time rinsing these areas. This is also where garden pests like slugs or earwigs might try to hitch a ride into your home. A thorough rinse ensures you aren't bringing any unwanted guests into your storage space.
Avoid Soaking
While you want to rinse away the dirt, avoid letting the rhizomes sit in a bucket of water. Rhizomes are like sponges; they can absorb too much water if left submerged. A quick, efficient rinse is all that is needed. Once they look relatively clean, move them immediately to a dry spot to begin the curing process.
The Most Important Step: Curing
Whether you wash your rhizomes or just shake them off, "curing" is the most critical part of successful storage. Curing is the process of letting the outer skin of the rhizome dry and toughen up. This creates a protective barrier that helps prevent rot and keeps the internal moisture locked in.
Where to Cure
Place your cleaned rhizomes in a single layer on a tray, a piece of cardboard, or a mesh screen. They should be kept in a warm, dry, and well-ventilated area that is protected from rain and frost. A garage, a shed, or even a covered porch works well. Avoid placing them in direct, hot sunlight, as this can "cook" the rhizomes and cause them to shrivel.
How Long to Cure
The curing time depends on whether you washed them and how humid your air is.
- If you washed them: They will likely need 3 to 7 days to dry completely. The rhizomes should feel dry to the touch, and any remaining bits of soil should be hard and crumbly.
- If you shook them: 2 to 3 days is usually enough to let the cut stems "callous" over.
You will know the curing process is finished when the cut end of the stalk looks dry and woody, rather than green and wet. The skin of the rhizome will also appear slightly duller and feel firmer.
What to Do Next
- Check the weather forecast for a light frost.
- Gather your garden fork, labels, and storage bins.
- Clear a space in your garage or shed for the curing process.
- Ensure you have a gentle spray nozzle for your hose.
Evaluating Rhizome Health
While the rhizomes are curing, take a moment to look at each one. This is the best time to sort your collection so you only spend energy storing the healthiest plants.
Healthy canna rhizomes should feel heavy for their size and firm to the touch, similar to a fresh potato. If a rhizome feels light, hollow, or "squishy," it is likely already suffering from rot or desiccation. These should be composted.
You should also look for "eyes." A healthy rhizome should have at least two or three visible growth points. Large, multi-segmented clumps can be stored as they are, or you can choose to divide them now. Most gardeners find it easier to keep the clumps intact over the winter and divide them in the spring when the eyes are more prominent. Keeping the clump whole also reduces the number of "wounds" or cut surfaces that could potentially rot.
Choosing Your Storage Medium
Once the rhizomes are cured and dry, they need a "bed" to sleep in for the winter. You shouldn't just throw them into a plastic tub and put the lid on tight. Without airflow, moisture will build up and cause rot. Without any protection, they may dry out too much.
The Best Packing Materials
We recommend using a packing material that can hold a tiny amount of moisture while still allowing the rhizomes to breathe. Popular choices include:
- Peat Moss: This is the gold standard for many gardeners. It is naturally slightly acidic, which can help inhibit fungal growth.
- Vermiculite or Perlite: these are lightweight, sterile, and excellent at regulating moisture.
- Wood Shavings: Pine or cedar shavings (the kind sold for animal bedding) are inexpensive and provide great airflow.
- Newspaper: If you are on a budget, wrapping each rhizome loosely in a few sheets of newspaper works surprisingly well.
The Container
Cardboard boxes, milk crates, or plastic bins with the lids left off (or with holes drilled in the sides) are ideal. If you use a plastic bin, do not snap the lid shut. Condensation will form inside, and by January, your cannas may be a mushy mess. A layer of newspaper on top of the box is a great way to keep dust out while still letting air circulate.
Finding the Perfect Storage Spot
The "right place" for storage is just as important as the "right place" for planting. Cannas need a spot that is cool, dark, and frost-free.
Temperature is Key
The ideal temperature range is between 45°F and 55°F.
- Too Cold: If the temperature drops below 40°F, the rhizomes can suffer "chill injury," which leads to rot once they warm back up in the spring.
- Too Warm: If the temperature stays above 60°F, the cannas may think it is spring and start to grow in the dark. This wastes the plant's stored energy and results in weak, pale sprouts.
Unheated basements, crawl spaces, and insulated garages are usually the best spots. If you use a garage, make sure the boxes are tucked into an interior corner away from the garage door, where temperatures fluctuate the most.
Winter Maintenance: The Monthly Check-In
Gardening doesn't entirely stop in the winter; it just moves indoors. Once a month, it is a good idea to peek inside your storage bins. This five-minute task can save your entire collection.
Checking for Rot
If you see a rhizome that has turned dark and soft, remove it immediately. Rot can spread from one rhizome to another if they are touching. By removing the "bad apple" early, you protect the rest of the box.
Checking for Shriveling
If the rhizomes feel very light or look wrinkled like a prune, they are getting too dry. You can lightly mist the packing material (the peat moss or shavings) with a spray bottle of water. You don't want the material to be wet—just "barely damp" to the touch. This provides enough humidity to stop the shriveling without encouraging mold.
Key Takeaway Successful storage is a balance. Aim for a "cool and goldilocks-dry" environment—not too wet, not too dry, and never freezing.
Preparing for Spring
When the days begin to lengthen and the soil starts to warm, your cannas will naturally start to "wake up." About four to six weeks before the last expected frost in your area, you can bring your boxes out of storage.
This is the perfect time to divide your clumps if you didn't do so in the fall. Use a clean, sharp knife to cut the rhizomes into pieces, making sure each piece has at least two healthy eyes. Let the cuts dry for a day before planting.
If you live in a region with a short growing season, you can give your cannas a head start by potting them up indoors in late March or early April. Place them in a sunny window or under grow lights. By the time the weather is warm enough to plant them outside (when soil temperatures reach 65°F), you will already have several inches of lush green growth. For more seasonal growing tips, visit our Garden Basic Essentials page.
Summary of the Canna Storage Process
Caring for your cannas over the winter is a straightforward process that pays off with larger, more beautiful displays every year. While the question of washing is a matter of preference, the goal remains the same: clean, dry, and healthy rhizomes.
- Dig after the first light frost has blackened the leaves.
- Wash only if you have heavy soil or want to inspect for pests; otherwise, shake off the dirt.
- Cure the rhizomes in a dry, ventilated area for several days until the skin is firm.
- Store in a breathable medium like peat moss or wood shavings.
- Maintain a temperature between 45°F and 55°F and check monthly for rot or shriveling.
At Longfield Gardens, we want every gardener to feel confident in their ability to grow and maintain these spectacular tropical plants. If you’re planning your order now, you can also browse Canna Medium Banana Punch, Canna Tall Tropicanna, Canna Tall Tropicanna Gold, and Canna Short Orange Chocolate for next season. By following these simple steps, you ensure that your cannas return year after year, bringing height, color, and excitement to your summer landscape. For more advice on growing and caring for summer-blooming bulbs, you can explore our other guides on our website. If you have questions about orders, take a look at our Shipping Information or About Us pages.
"Winter storage is not about keeping the plant alive in the sense of growing; it is about protecting the energy the plant worked all summer to store. A little care in the fall leads to a spectacular show in the spring."
FAQ
Should I wash canna bulbs if I have sandy soil?
If you have sandy soil, it is usually better to skip the washing and simply shake the rhizomes. Sandy soil falls away easily once it dries, and leaving a tiny bit of grit can help protect the rhizome from drying out too much during the winter. This "dry cleaning" method also reduces the risk of introducing excess moisture that could lead to rot.
How dry should canna rhizomes be before I put them in boxes?
The rhizomes should be completely dry to the touch on the outside. If you washed them, the skin should no longer feel damp or cool, and the cut stem "handle" should look dry and callous. If they are even slightly wet when you pack them away, the risk of mold and fungal growth increases significantly.
Is it okay to use plastic bags for storing canna rhizomes?
You can use plastic bags, but you must keep them open at the top to allow for air circulation. Never use sealed or "zipper" bags, as they trap moisture and gases that will cause the rhizomes to rot quickly. Many gardeners prefer paper bags or cardboard boxes because they naturally breathe and prevent moisture buildup. If you need help with an order or have a product question, our Contact Us page is the best place to start.
What happens if I forget to wash or dig my cannas until after a hard freeze?
If the ground has frozen solid, the rhizomes may have been damaged. However, if only the top inch of soil froze, they are likely still fine. Dig them up as soon as possible, inspect them for soft or mushy spots, and proceed with the curing process. As long as the core of the rhizome remained unfrozen, it should still grow in the spring.