They are in rich, moist soil and morning sun till about noon.
Why Are My Hollyhock Leaves Turning Brown
Certified GKH Gardening Expert
There are several things that could cause this. If you have had extreme temperature fluctuations (colder or hotter), the stress from the extreme temps may be to blame. The plant may also have a pest or a fungus (rust most likely). I would recommend treating the tree with neem oil, as it will take care of both pests and fungus. Here is more info: https://www.gardeningknowhow.com/plant-problems/disease/learn-about-plant-rust-disease-and-rust-treatment.htm