Hollyhocks must establish a root system first, and then they can produce the stalk(s) of flowers you love so much. Often they are planted in the fall to give them a chance to establish a system during the winter months. While other plants are loafing and going into dormancy, the hollyhock foliage is still green! When spring arrives, your fall planted babies will burst into growing
and produce blooms that summer. This is why most people plant them in the fall, but it is not a must. It is vital that you keep your baby hocks watered regularly to ensure a strong and healthy root system to carry it through the winter cold.
In fact, I almost prefer to begin mine in the spring because then you see them growing, you know they are growing, and if you need to, you can move them into their permanent positions before they get too comfortable. Though the spring planted may not bloom that year (some varieties do, but not much of a show) They have the entire season to grow root systems and foliage. The next spring, look out. Your plants will be HUGE and the number of flower stalks increased.
Fall planting is nice, too, but if you are looking for impact, spring planting one year before is (my opinion) the best way to go.
Spring planted the previous season will increase the bloomage.
Trying to start Hollyhocks on a heated germination mat is not advised. Don't try to rush your hollyhocks, they will come up when they get ready to. Don't assume that since package 'A' popped up in three days that all of your seeds should. The best way I have found to grow hocks is to lay the seed on the surface of well-tilled soil, then using a screen mesh collander, shake soil on top of the seed, a little less than 1/4" layer of sifted soil. Keep moist and do not let your seeds dry out once planted. Be patient and don't give up!
Backtracking on the fall planting, freshly harvested summer seeds sprout quickly,
while seeds which have been collected for spring planting are a bit slower to sprout.
But then again, you've got better things to do than stare at a tray of seeds, right?
Sweep that greenhouse, dust those cobwebs, time to garden!