| Brian, I'm assuming the flowers aren't affected. Though I'm no expert, I would suggest you remove any infected leaf and discard it in the trash (Don't compost!) My hollyhocks also have a recurring disease (looks like some kind of rust) showing up every year and affecting only the leaves. Although the flowers are ok, it makes the plant unsightly. Since it's a biennial I haven't been as vigilant as I should in discarding the infected leaves, and so the problem re-surfaces every year. The only other alternative for you would be to remove every infected plant and replace it next year with new ones.
Helene (canadian daisy) | 
