William ~ for sharing your experiment with us. I am always interested in using safe and natural products, if possible. It seems as though there are many strains of fungus that like irises.

For the rhizomes, I used 10% chlorine bleach, followed by Serenade, a commercial but organic antifungal. I only used the bleach solution after I saw mold on the rhizomes, but there is an improvement. There is growth taking place on all involved.

Evelyn, I'm curious if you know what kind of mold you had on your rhizomes? The only mold I've seen on rhizomes here is black, superficial mold on the surface of the rhizome. That kind of mold does not seem to damage rhizomes here, unless perhaps if it attacks a new wound on the rhizomes after surgery or division. Then I too use bleach on it. That mold seems to go away on its own in warm sunny weather.

William ~ No, I did not know, specifically, which mold it was. Just a black, sooty mold. Since this is my first year, growing so many irises, I did not want to take a chance on losing the whole lot of them. On the irises that are in mixed beds, I never really paid much attention to them for many years. I don't even know if some of those were lost or not. I didn't even put labels on them, as I thought that the plastic labels were unattractive. They are, so now I have metal tags and wire stands, to which I affix printed labels, with the Brother P-touch label printer.

Evelyn, that sounds similar to the mold that I have here and I believe this type of mold can grow anywhere it is too moist. Thanks for satisfying my curiosity.

Admittedly I probably should have waited a bit longer to see if there was any bad reaction, but as everything looked okay I sprayed the entire population of irises and lilies with the cinnamon mixture this evening. Smelled very nice in the garden!

I sprayed again a few days ago and while I haven't seen any burn damage, I'm a bit concerned that I might have partially damaged the wax layer on some iris leaves, so for this reason, as a precaution, I'm sorry to say that I'm going to have to end this experiment prematurely. Maybe I used too much washing up liquid or it was the rubbing alcohol or simply that I combined all these ingredients, but I feel it is best to be a bit careful.

Can't say that I've seen any reduced spread of leaf spot with these few sprays either, but I never expected any quick results.

Hot water is also an option for extracting the cinnamon goodies, so I will take this under consideration as well for future mixes. The fewer ingredients, the better.