Hi Rich..and Happy Veteran's Day. :-)

I started Hibiscus from seed winter sown 2 years ago and this year I had a plant bloom for the first time. I didn't get a lot of germination that year, but it probably was some fault of mine. I am planning on trying them again.

pm2

Hibiscus covers a wide diversity of plants- Some are hardy even here in MN- they can be wintersown easily, I had blooms from my first year ws babies this year- some are annuals that should do well if you sow when you wintersow your other annuals, but if you are asking a tropical beauty to give winter a try, I am not too sure what the outcome will be.
It might be a good idea to figure out which hibiscus you have and what it's habitat and growing requirements are to achieve the greatest success-
Sorry I couldn't be more help-

Julie