I can't think of anything off hand that would tolerate shading by the basal leaves.

.What Grows Well With Hollyhocks?.

1. "Hydrangea.. it suitable to grow in front of a row of taller plants such as hollyhock."
2. "Shasta daisy...thrive in the same growing conditions as hollyhocks."
3. "Bee balm...pairs well in the front of flower beds with hollyhocks."

Of course one can grow something in front of them but I agree with dbarron that nothing much will survive under them. They like sunny, well drained positions, even happy growing in paving, so anything grown near them needs to enjoy the same conditions. Mine are just self sowers on the allotment so they're paired with chard, kale and zucchini at the moment.... entirely fortuitously.

You could grow something taller like Monarda/bee balm to mingle with them, though you will need to pull a bunch annually to keep them from taking over. Perhaps growing a rambling plant such as the perennial Geranium Rozanne nearby where she can reach out toward the empty hollyhock space might work.

You could have a couple of pots of annuals to place in that part of the garden as the hollyhocks fade.

You won’t find anything that will thrive in the heavy shade created by the hollyhock leaves and then look good and thrive when exposed to a lot of sun late in the season, certainly not a sun-loving Sedum.

Faith, are the Sedum under the hollyhock or in front of them? Here anything literally under them would rot due to moisture.

You are right, Babs, the Sedum is really in front of them.