This season has been so strange for me that I didn't bother taking any measurements. Lots of cultivars had stunted scapes and flower sizes were noticeably smaller on some. Hopefully next year will be more normal.
I also don't trust the stats for the seedling since it was transplanted a few months before blooming to a pot with 3 other siblings (they had formerly been in the ground). We also had a drought and I didn't water them on a regular basis.
As for ruling out Double Sunset Glow, I realize that the picture I posted isn't typical of how it looks in my garden. It usually looks more like this:
Lack of water and fertilizer leads to a lack of pigmentation in some of my cultivars. I'm wondering if the seedling will change color next year if I do a better job tending it.
