What can I do to get rid of rust on my hollyhocks?
The Gardener’s Answer
Hello, Joyce: Hollyhocks are spectacular while in bloom, but the same can not be said for their foliage during most of the growing season. The most common problem with these perennials is rust caused by the fungus puccinia malvacearum. This fungus causes the foliage to look unsightly and in severe cases can cause plant failure; it does not affect the flowers. Rust can spread rapidly, especially during a wet spring like we have had in Kentucky. Good sanitation is essential in controlling the spread of this unmistakable fungus. It overwinters on plant debris, so it is important to clean up all remnants that have fallen. Removing infected foliage as soon as you see it in the spring will also help prevent further infection. Fungicides can be effective but they are only preventive, not curative. They must be sprayed at the first sign of infection and continuously during regular intervals throughout the growing season. As with any chemical, always follow application recommendations on the product label.