Hi Patrick,
" ...not a moot point. I actually will be planting Zinnia next Summer also - Yes, in the same garden beds as my Iris rhizomes. "
Oh. Good. Then my recommendations to Ginger can go for you, too.
The Zinnia marylandicas (Pinwheels, Profusions, and Zaharas) are probably best for you, due to their good resistance to Powdery Mildew. I don't grow them because breeding zinnias is my hobby, and the Marylandicas have 46 chromosomes and are incompatible with my 24-chromosome Zinnia violaceas (elegans). I do have to deal with Powdery Mildew, but since I prefer larger flowers and plants, I accept that inconvenience.
ZM
