Sandy, providing your temperature remains above freezing and
is frost free you can place the plant outside. This is not the best situation but
the minimal acceptable condition. You might consider dividing your plant as
well as using larger containers to maximize the plants potential. Your plant is
likely very tender and may be subject to wind damage; consider carefully where
it is placed until it hardens off after exposure to the outside elements. Kent

I can hold it in the house until it gets warm enough at night, and that's a good reminder to harden it off correctly before letting it stay outside. The pot it's in is heavy, so that's why it's stayed inside even on days in the 60s and low 70s. I've been carrying my small tangerine tree out in the morning and back inside at night because it's not as heavy.

Now you've got me thinking that I might not want a bigger pot, but instead divide it into a few manageable pots. I've got to get over my fear of dividing plants. I always feel like I'm going to kill them.

Well at least you didn't do like I did. Before I knew that I would like the canna lily, I ruined an entire season's tuber growth by digging it up and leaving it in water (I thought that will help wash off the dirt that didn't fall off). I was trying to relocate it or at least, thin it out if I didn't find a better place. Before I had a chance to get back to them, we had a freeze, and all the roots froze in that tub of water. That whole batch was gone, and I apparently did such a good job digging them up that no roots were left behind in the ground. It wasn't until almost 2 years later that I got some more canna and repopulated that area., after reading up more about them.

Canna roots are very robust. You probably have heard about how you should let some perennial roots callus over before planting them back in. With canna, I just chop right through it in the ground, and that is my "division" as I lift up part of the root mass. The remaining part stays in ground, even with a big gash totally exposed to dirt and bugs and microbes.

Then I just plant the part I took up in another area. No need to wait for that piece to callus over either. Even a piece as small as a thumb, if it has a growth node, will make a new canna plant.

Now that's not to say there aren't healthy ways to split a canna clump, but at least it can show you that you likely will not hurt it when you split it.

Now as you would have a 2nd year's growing season and probably end up with lots of canna in-ground or in-pot, you could contemplate about doing some tests to see if they would survive in-ground or in-pot in your area (including any of your microclimates, such as being near your house). Once you can determine how hardy they are, you might be able to see how it might remain outside even when they days and nights are not as warm as you think it is as a person, but it's fine for the plant. It might even be that they can remain in-ground during your winters.

So I'm believing I can divide without killing them. I'll do it when the weather warms up a bit more reliably. Now I'm stressing that I have to cut all that foliage off.

Cannas sound tougher than I knew. If I do get enough divisions, I might try planting some in the ground next to the house. I'm thinking the southwest side of the house would be best? I didn't think they could survive z5 winters, but last summer I noticed a stand of cannas in front of a fast food place in my area. I doubt they get planted new each year, so it's worth a try.

I had to lol at your frozen cannas. I bet most of us have some kind of story like that about something in our gardens. Good thing you tried again.