Foliage.

Taxonomists require the ability to see many parts of a plant including the rhizome, seed (its color and shape), leaf measurements, and texture of the underside of the leaf along with a multitude of physical characteristics to make an educated determination. I am not a taxonomist. Your plant closely resembles the species canna compacta often sold commercially as C. 'Robert Kemp'. I have always considered this species to be a most desirable species to grow for the gardener. You may want to do a search for the suggested name. I believe C. compacta is most commonly found occurring in Argentina, but apparently has been widely dispersed.
Kent

Thanks for the informative response! These do look a lot like Robert Kemp. Totally agree about them being great plants! These were moved in June and I still got a beautiful show already this year.

Still curious which is the native Canna(s), if anyone knows...?

If you are asking which canna species are native to the U.S.:
There are possible only three species that may be considered native to the U.S. and there is debate or I may say doubt as to whether even they were not introduced at some time in the distant past. Native Americans grew and used canna rhizomes and seed for a variety of purposes. These seed likely found their way from Central or South America into the U.S. Just because these specie cannas grow in the wild does not make them native to the area where they might be found. They were simply a non-native introduction. The USDA information is outdated and I suspect applies to what species are currently growing in the wild in the areas listed. Possible the best information source on canna species was completed and released in 2001 entitled "Taxonomic Revision of the Family Cannaceae" by Dr. Nobuyuki Nanaka. In this publication he list 19 canna species including 7 infraspecific taxa.
The specie commonly found growing in the U.S. includes canna flaccida, canna glauca, and canna indica L.
Kent

Thanks for the input! I must have looked at them too quickly the other day and have made a mistake. USDA does indicate C. flaccida and glauca as native.