Canna 'Ehemannii' is already blooming! This canna went through the winter dry in the clump of soil with which it was dug. It retained viable foliage - it never died down to a dormant rhizome as most cannas do. The foliage was in very dim light most of the time, really almost in the dark - but it persisted. Once the weather relented, the clump was placed outside in a place not exposed to full sun to allow the foliage to firm up. Once it got water, it surged into growth.
Last year this did not bloom until very late in the season; there are several other sprouts on the way up, so this one might be in bloom throughout the summer. The plant shown above is only a bit over two feet tall - later sprouts will easily go to double that and more.