It's rust. Many hollyhocks are very prone to it. Unfortunately it's one of those things that is best treated before you see symptoms--good hygiene at the end of the season (pick up & throw out leaves rather than leaving them around) and then there are some things you can spray earlier in the season that can help prevent it. But your best bet is for the future to go out and purchase rust-resistant cultivars since even if you do everything right, the susceptible ones can often still end up with it.
Not necessarily--you just need to make sure and clean up the leaves in the fall rather than letting them sit on the ground, and make sure to spray next year before the symptoms show up. But as I said, even if you do everything right the susceptible varieties can still get it, so you might consider replacing them with a rust-resistant variety if the look of the leaves really bothers you.
ecrane3 - You're one very busy gardender! Or I keep running in to you because we love the same plants - or both...I have rust on my HH, but ironically, they were just planted late last year and had no real major growth, thus no leaves lying around. Could it be from something in the ground as I read in an old post?
Also, that post showed a link to get rid of the rust - unfortunately, the link doesn't work any longer. Any ideas?
Thanks in advance and I hope you have a wonderful gardening weekend!
Rust can get around--if you have rust infected leaves and you don't clean them up you're pretty much guaranteeing that any susceptible plants in that area will get it the following year, but unfortunately cleaning up those leaves or not having rusty leaves lying around in the first place doesn't guarantee that susceptible plants won't get it. If you google controlling rust or preventing rust you'll find tons of information. You can't really get rid of it once a plant is showing symptoms, but you can take steps to reduce the chances of getting it again the following year. The basics of prevention are hygiene (cleaning up rusty leaves in the fall) and preventative spraying in the spring before (not after!) symptoms show up. But even if you do both of those things the plants can still end up with rust, so by far the best solution is to buy rust-resistant cultivars.
I got rust on my hollyhocks about five years ago. I dig up the hollyhocks and throw them in the trash bags-not my compost pile. Everytime I find a HH I dig it up and throw it away. I am still getting rust on the HH if I leave them in the garden. I recommend tossing them ASAP.
Rust is a fungi that spreads spores via the wind. It travels fast and is quite detrimental (and ugly).