I have 2 areas of edged plantings for random flowers. I will take as many flowerheads as I can collect and sprinkle the seeds all around through both and see what happens next year.
If it works, great. If not, I will pull up the weeds and try again. Its not like anyone is coming by to criticize those spots, LOL!
EVENTUALLY, I will have a weird unorganized collection of flowers there.