<<Certainly it's never shown any sign of self-sowing for me. Has anyone else in the U.K. (or elsewhere in Europe) ever known it do so?>> Well down here in Grasse (S France) it certainly does. One finds it growing from crevices in the old city walls (which says something for its tenacity). I've yet to find it growing in the open countryside, though. Eric http://ourworld.compuserve.com/homepages/E_Rowe 'Med wildflowers for Gardens'