Thanks, yes, I figured that out the hard way, lol. My records indicate this was labelled as Penhill Watermelon. And I now think it is. However, when I look at the progression from first bloom opening to a mature flower cluster the changes this big dahlia goes through are really dramatic. Mertyls Folly does a similar thing, but this the first year for this one in my garden, and I'm gobsmacked. So the photographs of it are a bit, well, not exactly misleading, but the present only an instant in the transition I've seen. Some dahlias open up and doesn't go through huge color changes, this one really does. I suppose I could post the pix of the first brick red coloured blossom to compare, but u can sort of see what I mean in this photo. Thank you for your note.
