All they need is

Water, water and more water.

deep water at the base of the plants.  

Do not spray from top with water.

That way you will avoid diseases and rust. 

Blooms will be large, and on strong plants. 

If you want to revisit your hollyhocks in winter, why not dry a few blossoms. 
Here is how

Dry them in a bed of builders sand.

Soon, they will shine another blooming season. 

Have a great week dear friends, 

Gina