Answer: Rust fungi are ever-present in the environment, just waiting for warm, humid conditions to favor their growth. The best deterrent is to grow your hollyhocks in a sunny place with good air circulation to help the leaf surfaces dry quickly and discourage the sprouting of spores. Remove any leaves that have the slivery-gray or orange growth on the undersides. If it looks like you'll be in an on-going battle with this problem, use Gardens Alive's Soap Sheild to prevent future outbreaks. Best of luck!
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