Marilyn, I figure the mother plant has to be sacrificed if you are intent on try to propogate from young stock; the trick would be to "first find your thicket", so that one can uproot some unwanted suckers. Sources both on the net and in reference books mention taking root cuttings as the preferred method for propogation. I hear romneya seed won't germ without gA3; is this your experience ? Attaching article from Coastal Grower Mark
Romneya instructions incleding root cuttins (Internet Document (HTML))