Karen.
WHAT kind of hibiscus is that???
Also, I have never heard of wintersowing hibiscus seeds... but I can always learn new things.
I only grew H. moscheutos (which over here are hardy for the cold winters, kills what's above the ground but always comes back from roots late in spring)
This is the one I call XXL, bloom up to 25 CM, about 10"
http://home-and-garden.webshot...
And a somewhat smaller one
http://home-and-garden.webshot...
Somehow only the first one produces viable seeds, I am not sure why!