Problems with Cannas

Hi I bought 2 canna Lillies a couple of years ago and planted them out, I did lose 1 over winter, but the other produces some leaf each year but never flowers. I have a sheltered, south facing garden on the South coast, so frosts not a massive problem, therefore I have just left it in the ground. Should I lift it to get it to flower next year? I have heard about a virus, is this why it's not flowering?

 

Need a pic, cant say without one for sure, regarding virus?

Might just be that it needs a flying start, they can be a bit slow getting going if left in the ground.

 

I think its a lot to do with temperature. I have two pots of Canna altensteinii, which were overwintered together as rhizomes. One pot was put outside after the last frost and is now one foot high, and the other has been inside my conservatory, where its a lot warmer. The inside one reached 8 feet and then had to be put outside as it was too big. It has already flowered, whilst the other isn't even thinking about flowering.