Heirloom Hollyhocks can grow to 10, 12 feet or higher. Some of my Mom's Hollyhocks topped out at 16-18 feet.
When I was a little girl, Mom and I would visit her sister's farm every August to pick chokecherries. While she was there she'd also wander about the Hollyhocks, pluck seed pods and stick them in her pocket.
Back home she'd walk into our big garden, crumble the pods, sprinkle the seeds on the ground
and, that was it.
Next summer, young Hollies would reach a couple of feet tall and put forth their first flowers.
The older Hollies provided a gigantic flowering forest for little girls with big imaginations.
When I bought my house, I purchased hybridized Hollies but they just never had the wild, farm garden look I was used to.
So... I did what any enterprising daughter would do. I paid a visit to Mom and stole some of hers!

Hollyhocks add big personality to your garden but they are hellacious reseeders. Cutting down stalks before seed pods dry helps keep them in check.

Heirloom Hollyhocks are generally single flowered, tall and lanky compared to hybridized varieties.
In well-tended gardens, Hollyhocks experience a disease called rust. (Which is why I never have that problem!)
Rust takes a foothold during the winter. Cutting down Hollys in fall and removing debris can save them from rust.
Flowers can only go to seed if they are left on the stem, undisturbed. Pluck Hollyhock pods from the stems when dry.
I have lots of heirloom Hollyhock seeds that have been flowering in my family's gardens for over half a century. If you want some, send me a note. I would love to spread some cheer by sharing these seeds. :)