I saved a double purple and white and the triple yellow indoors last winter and planted them out. The purple soon bloomed at 18" or so, but ran into some kind of problem (root problem I suspect) and finished blooming and just sulked and declined. It's just sitting there.
The yellow just kept growing and is over five feet tall now. Until about 10 days ago, there was no sign of a bud. But, now, it has finally given me some.
I cut the top off the plant in the pic, sorry. The poor little purple is in the lower right corner.
If I get any seeds, I'll D-mail you. If they get close to maturing when the frost comes, I'll do what I've done before: cut the stem and set it in a glass of water for awhile. If they're close enough to being ripe, they'll finish off indoors.