The reputable nurseries in my area will not carry I. walleriana. But there were a few of those parking lot pop up stands that sold them last year. They had signs that they would guarantee the plants for 30 days. Crazy because it was about 30 days before you would notice they got the mildew. And frustrating because they are just allowing the disease to perpetuate.
I did read, I think in Garden Gate Magazine, they have come out with a resistant variety.
I myself will just wait several years and see if it cycles out.
