Hi Itre
to All Things Plants.
Many folks may not be on Facebook so if you can post a picture of your unknown Hibiscus here on this page we might be able to give you an ID. Your evergreen Hibiscus may be the Tropical Hibiscus (Hibiscus rosa-sinensis) which come in many different colors. You can view photos here in our database:
http://garden.org/plants/searc...
Regarding the "quite a few plants in your yard that you don't know what they are" - We have a Plant ID Forum here on ATP
http://garden.org/forums/view/... and if you scroll to the bottom of the page and start a new thread with photos of your unidentified plants, I'm sure someone will be able to help with identifying them for you as well.
Again, Welcome!
Lin
Lin