Hi Kay,

Your hollyhock has hollyhock rust. It is extremely common. Hollyhock rust is a fungus and host specific. In this case, that means it attacks plants in the Malvaceae family. That family includes hollyhocks, hibiscus, rose of Sharon, and others. It's a tough one to control because there are several "weeds" that are susceptible. If you live close to a neighbor with a rose of Sharon, hollyhocks, or other plants in the family, and they get infected, then the spores from the fungus can drift into your yard and infect your plant.

Here is an article from the University of Wisconsin on hollyhock rust. 

Here is a fact sheet from Cornell. 

There isn't an easy answer or control method. I ended up removing my hollyhocks because my neighbors on both sides have weeds in the Malvaceae family (mainly rose of Sharon) that host the disease. I knew my hollyhocks would continue to be be infected annually by spores blowing from their properties. 

The links above provide information on prevention and treatment.