This rust is a fungi that causes disease in hollyhock plants, specifically. This one was found at the UW Farm on campus. The fungi is represented in the image as small orange dots called spores which spread by reinfecting the host plant. The spores are produced over winter and released in Spring. Once the spores become darker, the other side of the leaf dries and rusts as in the image below. It is best to remove the rusty leaves to avoid spread of the disease. As with many leafy plants, it is extremely important to not water the leaves in order to avoid disease and boost production.
