I'd be more worried about the canna drying out.

They need shallow, wide pots, the rhizomes go down about 8-10" or so.
Boca Joe

Thanks so much for responding Boca Joe
The actual pot I have is not the same dimensions as the link, but it is the same material.
The one I have is 16 inches wide and is 12 inches deep.
Would this be okay?

it still seems a bit small to me. I grow about 50 cannas in pots each year.

It would dry out much quicker in that size pot, it would grow and bloom though. It may also blow over in a thunderstorm just because of the shape.

let me know how it does.

Boca Joe