Name: Michele Roth N.E. Indiana - Zone 5b, and F (Zone 9b) I'm always on my way out the door..
I think it's mostly due to our frequent freeze/thaw cycles here; ice forms on the crowns during a cold snap and then a quick thaw will set the rot cycle in motion. Most delphiniums are very short-lived here. The longest I'vd had a delph plant live is three seasons.