Hollyhocks are a biennial flower, but are sometimes mistaken for a perennial because they reseed so prolifically and reliably. To establish your first planting, however, requires direct seeding. Hollyhock seeds can be seeded in the spring, or--in some climates--in the fall.
When to Direct Sow Hollyhock Seeds
In climates with mild winters, hollyhock seeds can be direct sowed in September. The seeds will germinate and begin to grow, allowing earlier bloom the next summer. The newly-started seedlings may be heaved out of the ground in areas where winters are subzero; those plants may not survive the winter.
In all USDA zones, hollyhocks can be sowed in the spring, up to two weeks before the last expected frost date; they can also be seeded at any time throughout the summer. Some hybrids may bloom the first year if started early in the spring, but in most instances, the blooms the second year will be much more impressive. Protect hollyhock plants over the winter with a four inch layer of leaves or other organic mulch.
Once established, it's unlikely that you'll have to reseed hollyhocks in the area in which they were started. If you'd like to start another stand of hollyhocks in another area in your garden, it's very easy to save the seeds from your plants. The seed pods will form as the flower petals fall. Pick the pods off the plant when they are dry and brown. When you peel off the outer husk, you'll find the disk-shaped seeds lined up in a circle on the inside.