Will someone please help with my snapdragons?
I planted snapdragons a few years ago. I have never done anything to them, but they survive through the winter and bloom great in the spring. I will trim them down when they get bushy. They bloomed great this year, but last week I noticed of them looked horrible. When I took a closer look, I saw that the leaves all had a yellow tint to them and there are brown spots all over the stems and the undersides of the leaves. They are almost completely covered with these spots and the plants look very close to dead. When I rub the spots I am just left with a brownish powdery substance on my fingers. The nursery said it is mites, but it sure doesn't look like mites to me. Could this be rust? I've never seen it before. If it is, can I just cut the plants to the ground and let them re-grow or do I have to pull them all up?