Some links again, I’m afraid.
Instructions to fold the standard sort of paper rose are available here and here. It’s fairly pretty and doesn’t look impossible to make (admittedly I’ve not tried it yet due to lack of paper).
Scroll right to the bottom of this page and you’ll see that there are several different roses available. Those interested in the Kawasaki Rose can find a modified version with a stem here.
Finally there’s a totally different rose at this site.