I purchased several cannas two years ago and I was told to dig up bulbs and store etc.. Well we didnt, and the plants that were originally purple and white cmae back with this large! plant that has varigated beautiful BIG leaves and only two huge white flowers came up. Then recently this pod looking thing shot out that has what I am assuming is large seeds(many) inside of it. This plant is about 3.5-4 ft. tall and just went wild this year. Everyone is asking what it is. I dont know, but it doesnt look like the little colored cannas I had before. Another pod is starting to grow. I am in Michigan also, if that helps any.
You left canna rhizomes in the ground overwinter in zone 5 and they lived? Were they very close to a south facing foundation of your house? Kinda rare to have unprotected canna in zone 5.
Are you sure it is canna lily? Seeds don't really sound like what I have. Seeds are large, but I don't usually have many. Can you possibly post a picture?
there is no purple canna. I am wondering if by any chance you might be talking about glads. Also, it is possible (though not very likely) that your plant is in a warm enough area of your garden and that is why is has come back. Also, if you have protected with heavy mulch, that might help the situation.
As pic will be really useful in giving you definitive ansnwers.
