Last year, I saved as many seeds from the Cannas as I could collect, with the intention of starting all of them as new plants. Because everybody -- I in particular -- always needs more Cannas. It wound up being about 150 seeds, which I sanded down and soaked in water for a couple days, as you do, and then I made a bunch of little holes in a bed in the yard and dropped a seed in each hole. Flooded the bed with water a few times, and then . . . nothing happened. There was a long enough delay that I concluded that the seeds had died, and I was really disappointed about that (not to mention all the time I thought I'd wasted on seed collection and sanding and so forth).
But after I'd given up, the seeds began to sprout. I don't have anywhere near the 150 I tried to start, but I counted 22 up five days ago, and 37 yesterday, so we may be getting there.
I can't remember where I saw it, but at some point I was doing research about whether or not Cannas can bloom in their first year from seed, and if I'm remembering correctly, it's possible but not certain. I don't really have any strong feelings either way: I'll have flowers from the parent plants whether the babies flower or not. At this point, all I really care about is that 1) it turns out to be possible to start Cannas from seed, like everybody says, and 2) whether they're going to grow fast enough to shade out all the weeds. (I'm already pretty tired of pulling weeds, and it hasn't even gotten hot yet.)
I should also remind readers that the book giveaway remains open until Friday, so if you missed that post, check it out and leave a comment.