all my plants are way too thick for me to figure out if they are coming from the same fan or not
If each cultivar is a thick clump then chances are that you have much less rebloom than you could have - possibly none at all.
Weeds growing in daylilies compete with them and reduce their growth and flowering. However, in a thick clump of daylily fans, even when kept well-weeded, the fans compete with each other - called self-competition.
Munson, in Florida, presumably had very good rates of fan increase (probably 8 to 1 per year) and recommended that clumps be divided very year otherwise their performance suffered. I don't expect that most locations or growing conditions get that sort of increase but I would strongly recommend dividing clumps that are approaching 20 fans in size if one wants good rebloom (and of course fertilizing well for strong growth rates, etc.)
