Brown spots on petunia blooms
My red petunias have ugly brown spots. The adjacent purple ones do not (yet). Humidity high at times, but usually there is no visible fungus until the end of the season.
King County Washington flowers: annuals and herbaceous perennials
Thank you for your question. Are you able to send a closeup photo? You don’t indicate whether the spots are on the leaves or petals. I suspect it is a fungus, and that diagnosis may require an exam under a microscope at your Extension office, but I’ll try. Thanks!