I doubt very much if I could get the rebloom here that Maurice mentions due to our city water. Our city water is not good and I have watered plants during dry spells and have not seen much improvement. If mother nature cooperated and gave us ample water during the summer, maybe I would get the rebloom. I do fertilize before bloom season with Scotts slow release flower fertilizer and I also use milorganite. I did have more rebloom last year than I have ever had in my 20 years of growing daylilies. I will try an extra bit of fertilizing this year after bloom season to see what happens.

Can't remember if it was year before last or the year before that but we had a very wet summer here in S.W. Ontario . For the first time in about 12 years of growing daylilies I had H. Flava rebloom. Now that was a real shock to me as it usually blooms the end of May here and then that's it for the season , but not that particular year . So was it because it was a wet summer or cooler grey sky summer ? I have no clue . I do recall this distinctly because it was such a shocker . I even dragged my DH off the porch to see what to me was a real oddity.

Here in my Z:5 garden, these are reliable reblooming diploids. I feed them Alfalfa pellets and meal along with milorganite, compost, worm castings (on some) and top dress with mulch to reduce moisture loss, thus reduce watering frequency. I sometimes add other stuff to the feeding menu like Osmocote. Last season I used some Spray And Grow sparingly. I still have most of it left over for this season. I have used fish emulsion in the past also. There is no limit to what you can try and use for your garden. When I started the new beds I used the mycorrizae (spelling ?) Fungi. My list :
Stella's Ruffled Fingers
Stella's Pink Pretty
Stella's Sparky
Rosy Returns
Apricot Sparkles
Endless Heart
On And On
Bitsy
Blackeyed Stella
Happy Returns
Centerton One
Going Bananas
Yellow Lollipop
Sunset Returns
Vineland L'uva
I am sure that there is more but these are definitely the ones I can recall right now.
For bud building hands down one of the best if not the best, the late blooming Genesta which have put out over 140 buds in my garden. I believe a picture of the scapes are in the ATP database. Only the frost stops her from going further with more buds protruding at frost kill.

very much Mike for your list. I will look up and research about the daylilies on your list. I am interested to find daylilies that have instant and extended rebloom trait for my hybridizing goal. I don't need high bud count, just reliable rebloom and blooms that open perfect most of the time.

Karen you are !