I have some that sound like what you are describing. Do the leaves have a bluish tinge to them? How tall do they get? One thing I've noticed about this particular canna, which came from my neighbor, is that they don't seem very consistent in my garden and the caterpillars really like their leaves. By inconsistent I mean they don't come up every year. When they do, they are beautiful because of that little yellow outline that really makes them glow!

Here is a link to a picture of my 'Hybrid.' From the research I've done, it's appears to be a Lucifer Canna and I can't imagine where it came from. All my bright green leaf cannas have always been red (species unknown) until this jewel appeared. I hope it blooms consistently every year! I love it!

Here is a link that might be useful: Susan's Garden

Very pretty!