I work in a 3-acre private botanical garden on the Sunshine Coast of BC and we're trying to deal with a number of diseases, Iris Leaf Spot being the main concern right now. Irises are treasured favourites in this garden and leaf spot on the rhizomatous species/varieties has become a serious problem. We destroy seriously affected leaves and try to keep all iris areas free of old diseased leaves, but this has not really reduced the problem significantly - and what should be a beautiful plant, whether in flower or not, has become a disheartening eyesore. The owners of the garden are loathe to resort to chemical sprays but I think we'll have to go there. My questions are: has anyone used any fixed copper sprays that have REALLY worked well? does anyone have an opinion on this kind of treatment? has anyone found a good fertilizer for irises (or other perennials) that doesn't involve "scratching in"? (we've recently resorted to a pelleted fertilizer - Osmocote - but it has way more nitrogen than most perennials need) does anyone know if this disease affects or is hosted by any other plant? I really appreciate any info on this topic. Natasha
I don't think we have that product in Canada - is it a fertilizer? what is its NPK ratio? is it granular or water-soluble? Thanks.
