I don’t get rust on my Hollyhocks - I do get that on my roses in the spring. I use hollyhocks to cover up my back fence and the back end of my neighbor’s garage that abuts my property.
I planted those hollyhocks from a six pack from the local nursery - I’m still hoping to get a yellow one.
Yes, the yellows seem to be rare in Hollyhock.
I forgot how big they got, so I planted ONE of the black ones (Nigra) in one of my raised garden beds. It was so vigorous it was crowding out Coneflowers, so I moved it to a spot - and Beau mowed over it a few times without me knowing. I was wondering where it went! Oh, well, seeds are cheap. If I can get him to move one of his junk piles (he’s SUCH a FARMER!) I’d have a perfect spot for a bunch along the barn wall.
Also - they are a biennial, so you may want to plant more this year, too, so they’re staggered in their bloom cycle so you’ll always have blooms each year. (You probably already know this, if you’re a Hollyhock Fan.)
And Hollyhocks were originally popular with Victorian Ladies. They would plant them around the Outhouse, so other ladies knew to ‘look for the Hollyhocks’ when they needed to use ‘the necessary’ and wouldn’t have to ask out loud where it was. :)