Last year I successfully overwintered my canna in a large pot by keeping it in a room that is usually around 55° during the winter months. I would like to do the same thing this year, but we had a lot of rain and then the temperatures quickly turned to freezing (high 20s, low 30s) and the tops have died down. I'm thinking that the wet potting mix is either going to cause the plants to start re-sprouting if I bring them inside, or cause the rhizomes to rot. Is there any way I can leave them in the pot? Or would it be better to just remove them from the pot for this winter to store them?

I would probably take it out of the pot and either put fresh mix in and replant, or dry store for the winter. I've had the rain than freeze incident happen before and the tubers rotted. Now I put the containers on the covered porch for a few weeks prior to anticipated freeze.

Thanks, Rj - I should have just asked you in the first place!
I'm kicking myself for not moving the pot into the garage before we got all the rain .

I want to divide it up next year anyway so I'll just dig out whatever is in there before it has a chance to rot.

Down here... cannas send up new growth all winter... and that growth gets burned back when it freezes, and it doesn't seem to be a problem.
I'd bring the plant in and not give it a second thought.... when the canna sends up fresh growth, try and put it where it gets some light... see if you get nice flowers through the winter months!

Stone, do they just keep flowering all year for you, then? I have to say it would be fun to have this one flowering - or even just with the tropical-looking leaves - in my sunroom over the winter. I'm not sure it would get enough light, though; the sunroom has low-e glass, plus we are already close to having just 10 hours of sunlight per day.

Sorry, at my house... the new growth keeps getting frosted back during the winter months...

If I brought them indoors, or under glass, I'd expect winter flowers, but... I have enough stuff to winter over indoors, no need to protect the winter-hardy stuff...

10 hours of sun should be more than enough...
They bloom in the shade garden down here...

Sandy, @weedwhacker

I'd think the potting mix in that would dry out fast enough to just bring it in as-is and allow it to dry. I do that with mine. Keep in mind that cannas love water. [Edit: I meant, when growing. So the moisture in the pot was not likely to be detrimental.]

I've learned that at a comparable room temp my overwintering potted ones benefit from light remoistening during the winter. Otherwise some of the roots do dry up and die.

I don't know if you can bring them to flower but you can keep them going with leaves all winter. I've only done that with one, takes too much watering to keep them going.

Cannas are never fully dormant naturally, so far as I can tell. The treatment they're generally given in cold zones, holding them bareroot over winter, is something they tolerate rather than benefit from.

[Edit 2: I should have mentioned that I've also seen that cannas can be somewhat cold-hardy. Although the tops may freeze to the ground, the crowns and tubers can survive if adequately protected. I saw some Tropicanna ®️ 'Phasion' that had overwintered outdoors in Cincinnati and thought I'd try it here. Just far enough further north here, zone 6a instead of 6b-7a, or a just-bad-enough winter, but mine didn't survive when I risked them.

[Edit 2, cont.] However, when I planted some other cannas next right to my foundation against the concrete wall with the heated basement, they survived. I had seen this in a northern Missouri zone 5 garden with cannas planted smack up against a brick fireplace wall that also adjoined a heated basement.]

[Edit 3: One year, after I brought them inside, I kept the 'Phasion' cannas growing well in their (large) pot next to a tall SE window with full sun and they grew slowly but well and colorfully for most of the winter. Then in January, I was too busy to keep them watered and I allowed them to die back. They took off again and were fine the next spring.]

.....

In FL we leave them in the yard. The stems from last year have seeded and fallen over now but they are already sending up a new set if shoots. The weather patterns here is generally semi-wet in winter. When a cold front approaches, it hits up against the warm air already in place and triggers rain. Then the front sweeps by and the colder drier air settles in for however long. The rain is actually beneficial, it waters everything and if it freezes they are hydrated and better prepared for cold.
Cannas are in the same family as gingers, heliconias, bananas. They do not stop growing, even if the top growth is knocked back by a freeze

Sandy, I think your wet pot brought in, to go gently dormant, will be ok.

As to cold hardiness, here in zone 7 (b?) I still see most of the indica roots freeze and rot. Covering them with leaves and their own stems one year- rot.
Given how huge the indicas grow in one summer, (needing dividing) and how nasty it is digging up rotten ones, I dig them all up.
Tropicanna roots for me haven't grown nearly as vigorously. Hard to keep my pots watered as much as they want, I think. But I am going to leave a few in the south facing foundation bed ( zone 8? +?) and see how they do.

Thanks for all the replies - and I suspect this thread may be quite helpful to other inexperienced canna growers with similar questions . I envy those of you who are able to leave the plants in the ground throughout the winter, here the soil can freeze solid 6 feet deep and it seems like a miracle to me that anything can come back up in the spring. I've dug down into the side of the pot for a ways and it doesn't seem as wet as I had imagined it would be, so I'll just cut the (now dead) top back and allow it to continue to dry out in the garage. The worst that can happen is I'll buy a couple of new bulbs in the spring!

When I lived in OH, I put potted Cannas in the dark, cool basement after frost toasted the foliage, and forgot about them until spring. You can also pull them out if you want and store in the basement that way, but it's more work.

Also works with elephant ears (Colocasia esculenta, specifically.) Handy because the couple times I tried to keep them growing, they got spider mites so bad the foliage was ruined anyway.

Thanks, Tiffany . I did manage to overwinter this plant last year by keeping it in the pot, in our "workshop" which stays in the low 50s for temperature even in our coldest, below zero, weather; other than it starting to sprout way too early for me to put it outside, it did fine (last year I stuck it under one of my seed-starting grow lights for a while, this year I plan to move it back to the unheated garage once the weather begins to warm up, to try to delay it a bit). The main issue this year is that it got so drenched with about a week's worth of rain, and I was worried about that causing the rhizome to rot; however, on further review (as they say), the potting mix doesn't seem as wet as I thought it would be and I'm just going to go ahead and cut it back and hope for the best again. It had a lot more stems this year compared to it's first year, so I'm planning to divide it into 2 pots in the spring - assuming all goes well!

I have to say, it's been very interesting to read comments and suggestions from members in different parts of the country - thanks, everyone!

The workshop sounds perfect! It must be heated & well insulated. My kitchen doesn't stay that warm when it gets down in the 20's here.

It's best to avoid leaving the canna rhizomes in wet potting mix over winter as this can indeed lead to rot, especially with the temperature fluctuations you've described. If the tops have died back and the soil is wet, gently remove the rhizomes from the pot, clean off excess soil, and allow them to dry for a few days in an area with good air circulation and no risk of frost. Once dry, store them in a cool, dry place in peat, vermiculite, or a similar material that will keep them from drying out completely. This should help ensure they don't rot and are ready for replanting in the spring.

purpleinopp said: The workshop sounds perfect! It must be heated & well insulated. My kitchen doesn't stay that warm when it gets down in the 20's here.

Tiffany, brrrrr! The shop isn't "technically" heated, but that's where the furnace (a hot-water boiler) for the whole house is located and it gives off enough heat to keep that area reasonably warm. My seed-starting setup is also in there and the plant lights help warm the shelving unit (which has clear plastic wrapped around it as well).

Mohsin1970, thank you for your suggestions; you didn't say where you live but as our weather turns colder the humidity levels indoors drop quite remarkably, and also, as I mentioned above, the potting mix doesn't seem to be as wet as I had initially feared. Hopefully my cannas will be happy enough and come back up in the spring .

Hi @Mohsin1970
While that may be the best advice, I find my canna indica to be almost indestructible. And given how much they grow in one season, and I cannot even give away all the excess, I do minimal cleaning, and have almost zero loss. Now, with my little Tropicanna, which haven't grown much over the season, I might take more care.

What has been YOUR experience? Have you more experience with hybrids, for example?