Canna lilies make for a remarkable display during their bloom time, but these wonderful perennials hate the cold. So how do you go about overwintering canna lilies in pots?
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.
How To Overwinter Canna Lilies In Pots?
Overwintering a canna in its container is nearly identical to overwintering a rhizome you’ve excavated for the winter.
The biggest difference is that you won’t need to uproot the plant before storing it.
Some Pros And Cons Of Growing Cannas In Containers
There are many advantages and disadvantages to growing any plant in a container, but knowing how the two compare will help you decide whether overwintering in pots is right for you.
Here are the pros and cons which affect cannas the most:
- Better control against overwatering
- Can simply bring the plant indoors when it gets cold
- Potted cannas can be forced (i.e. made to bloom early)
- No need to uproot annually
- Cannas can get overcrowded faster
- Soil builds up toxins faster
Digging Up Garden Cannas
Let’s say you have a planted canna in your garden and wish to move it to a pot.
The Autumn uprooting is a perfect time for this.
Cut back the canna foliage to about 3” inches once the first light frost hits.
At this point, the leaves will be dying and can no longer photosynthesize efficiently.
Follow all steps as you would usually, but decide whether you wish to pot now or in the spring.
If in the spring, continue with standard storage methods.
Autumn Potting A Canna Rhizome
It’s usually best to pot the canna rhizomes in pots when it’s time to plant for the spring, but you can also pot them in autumn.
Many growers prefer to use pure sphagnum moss as a storage medium, which will work in containers.
Simply follow the same steps as you would typically to divide the rhizome.
However, instead of putting more than one in a container, give each their own pot, then store them as normal.
Come spring, you can replace the moss with a good canna lily potting soil, making the container it’s new permanent home.
Overwintering A Potted Canna
As mentioned before, overwintering a canna that’s already potted saves a lot of time and effort.
When dealing with an indoor canna, there’s very little you need to do outside of pruning back the dead foliage.
Outdoor containers will need to be brought inside after the first light frost.
For these plants, you will want to cut the foliage down to ground level.
Keep the pots in a cool, dry location and stop watering or fertilizing your cannas.
The storage space should have temperatures above 40° degrees Fahrenheit and be no higher than 50° or 55° degrees Fahrenheit.
Can Cannas Continue Growing Indoors?
The answer to this question is a conditional yes.
No matter what you do, these plants will need a rest period.
You can force the rhizomes to make them bloom early, but there will still be a brief dormant phase. Learn about canna bulb storage here.
To keep the cannas growing during winter, you’ll need to bring the plants indoors before the first frost hits.
They need a spot where they’ll get plenty of bright, indirect light.
Grow lamps can be a valuable asset here.
The humidity and temperature can be kept the same as if growing them indoors during the growing season, but you’ll want to cut back on water and food.
Be warned: Attempting to keep your canna growing throughout the winter can weaken it and make it more susceptible to infestations.
You also won’t be getting much benefit from keeping the foliage during this time, so it’s usually best to cut back and store.