Canna plants are one of the easiest tropical plants for the gardener to overwinter – which is especially handy since they are also one of the most versatile plants for the summer garden. With their large, often colorful leaves and unusual, repeatedly blooming flowers in bright, cheerful colors, they give garden beds and containers a lush, exotic look. The plants also feel at home in water features on a partially shaded terrace. You can find out how to overwinter canna from our article!
How to overwinter Canna
You don't need a greenhouse to overwinter canna. The thick, fleshy rhizomes can be easily stored in a cool cellar, garage, or cellar in complete darkness - without heat lamps, timers, or expensive lighting systems. So if you've worked hard to get one this seasonnice collection of tropicalIf you're starting cannas and hate watching them die from a cold winter, follow these simple steps to keep them blooming and multiplying in your garden for many years to come.
When should you dig up the rhizomes?
While cannas send tropical leaves skyward during the growing season, they also spread into the ground, forming shallow-rooted clumps of thick but brittle rhizomes. Fall and freezing temperatures signal that it is time to dig up the rhizomes for overwintering. Wait until frost has visibly blackened the plant's foliage before digging - usually in mid to late fall. The trick is to get the plants out of the ground before temperatures drop sharply and the ground freezes.
How to Dig Up Canna Lilies for Overwintering
Use a digging fork to gently pry the clump out of the ground. Since canna lilies have shallow roots, this is easier than you think! If you overwinter Canna in a pot, you can either store the plants together with the pot or remove the clump from the pot and do the same as with plants grown in the garden, depending on how much space you have. Plants grown in pots need to be transplanted into fresh soil next season for best results.
Separatethe rhizomeswith your hands. Use caution, but don't worry if they break. The fleshy roots dry out during storage. If the rhizomes have been stored in garden soil, they must not be washed as this will cause disease problems during storage. Instead, remove the soil and brush it lightly. However, if they were in a swampy area or pool of water (cannas make great pond plants!), it is wise to remove a long season's worth of dirt and debris.
Using a clean knife, cut off the old petioles 1-2 cm above the rhizome. Then carefully inspect the rhizomes for rot or animal damage and discard those with signs of disease. If it is a large rhizome, you can use a clean knife to cut away any rotten or damaged areas down to the clean, white flesh. Remember that different canna strains look the same naked. If you're digging up multiple varieties at once, place them in large, labeled cups (even if it's just a piece of paper you add).
Store the rhizomes properly in winter
Now comes the easiest part of all – preparing the plants for storage. Traditionally they are stored in containers or bags filled with slightly moistened peat moss or wood chips. However, if you're short on time or don't have any of these materials available, you can overwinter cannas by simply placing the sorted rhizomes in heavy-duty trash bags. The bin bags help maintain good moisture levels without adding additional moisture. However you store the rhizomes, be sure to carefully label the bags or pots.
Recommended storage locations for winter storage
Find a cool, dark spot that stays above freezing but below 13 degrees Celsius throughout the winter. Non-fluctuating temperatures are best as they prevent early sprouting. Some recommended storage locations are:
Keller
Crawlspace
Unfinished basement rooms
Unheated garages
Deep cold frames
Avoid outbuildings (barns, greenhouses, etc.) as temperatures often drop below freezing in the depths of winter.
When can you plant the flowers back in the garden?
As temperatures rise and spring returns, check your rhizomes again – discard any that are rotten or diseased, and if some begin to sprout in storage, moisten them lightly with water to replenish resources. Cannas aretropical plantsfor the warm season. Not only will they be damaged if you plant them in the garden too early, but they won't grow vigorously until temperatures are warmer.
Natural timing for canna rhizomes
Keep your storage rooms cool and, as soon as there is no danger of frost, plant the rhizomes outdoors or in containers in nutrient-rich soil with a small amount of a balanced fertilizer. It takes a while for the foliage to sprout again, but then it's ready for the summer garden. If you plant the plant in a water feature, be sure to cover the bottom of the container with at least 2 inches of gravel to keep the soil firmly in the pot.
Overwintering canna: practical tips to make the job easier
- If you use a garage or other room, you should start clearing out space in late summer.
- Look for multi-tiered rolling carts so you can keep all your dormant plants in one place and easily put them away when needed.
- Convert a raised vegetable bed into a mini greenhouse in early spring using flexible PVC pipe and 6ml plastic so you can get your cannas into early growth.
- If you have many specimens of a particular variety after many winters, consider keeping some of the rhizomes in placeto overwinterand cover with a thick layer of mulch (16-20 cm) - especially if they are in well-drained, sandy soil.
