Fantastic garden performer , vigorous, bushy, extremely free blooming . New stems seem to come out of every leaf axil and end in a beautiful bloom. The color is the cool side of yellow...like distilled clear autumn sunshine, very refreshing, mixes easily with most other colors, and is among the most colorfast of yellows. There is no tawny orange or pink shading, it’s a true yellow. Blooms hold decent size and petal count in heat, despite Weeks’ comment about better size in cool weather, Mellow Yellow bloomed right through my Texas heat wave where temperatures soared to 110 degrees. Overall I think this is a huge improvement over older yellows such as Oregold or Midas Touch. Somewhat underrated and underplanted in my opinion, this is my top pick for a true yellow HT.