hollyhocks

Does anyone know what to do with a 2yr old hollyhock? It flowered last year and has flowered again but this time it also has little red marks on the leaves. I don't know if I leave it in the ground once it has stopped flowering or if I cut it back.
My gardening skills are still developing
The nice plants I lovingly watered last year turned out to be invasive weeds

Hollyhocks are a perrenial but are prone to rust so are usually grown as biennials(dug up at the end of the second year & new ones planted. My gardening guru Monty Don has this advice