I have had great luck getting my cuttings to root. The Hibiscus was a double salmon and I cut it back each year when I put it in the greenhouse and it comes back and blooms each year. It got so big I had to give it away since I ran out of space in my greenhouse. If you look up your hibiscus you will see the best time to cut for rooting....here is a link from a printout I had when I was propagating it. I do not know if the link is any good anymore. I printed it out in 2009.
http://www.trop-hibiscus.com/r... the title was Tropical Hibiscus - Propagation by Rooting. If the link does not work, search for that title and see if you an find it. Hope this helps.
Good luck.