I grew mine from seed this year, and they are doing surprisingly well. Last year, the nurtured plants sulked in the cold of early summer, but made up for it by flowering their socks off from mid-August to November. (They would have kept going until Christmas I think - but I cut them down and removed them before the frost could make them into a sorry mess!)
So I wouldn't give up just yet - I have high hopes that a bit of sun (please) and therefore better light and warmth will send them into ecstasies of flowering!