Hi. Ref the double Daylily possibly appearing "under its own steam" a similar thing happened with this plant. I bought this semi double/double called trachelium "Bernice" many years ago - there is also a white and I do believe now also a pink (not pos on that). I have found that Campanulas readily seed around and I have had whites appear from blue plants particularly with the peach leaf variety. Had a lovely white semi double appear from this one which has stayed true and permanent - not yet flowering.