Like much of the eastern half of the United States, we here in New England have had an extraordinarily mild winter. Even so I was surprised when I took a different way home today and came across two clumps of what appears to be Canna indica 'Mactro', more commonly known as Tropicanna Gold Canna, vigorously resprouting after evidently overwintering in place.
...And the other one a few feet away on the same property
I vaguely remember cannas of this variety flowering in this frontyard last summer and fall. Their location at the foot of a south-facing wall must have offered extra protection, and might also go some way towards explaining that they are already so far along in terms of regrowth. Even if last winter was exceptional, this makes me wonder if with careful siting and a heavy winter mulch, in-ground overwintering might be an option for cannas in the garden back in Michigan, somewhat similar to how I treat my Japanese fiber bananas (Musa basjoo). There is not really any suitable place in the house to overwinter the rhizomes and I am usually not around to dig them up in the fall and start them up in the spring, so this might be a way to have cannas again despite those obstacles.