Identified by Ivan Pepelnjak after I'd visited his site: http://www.zaplana.net/index_en.asp. This is apparently quite a common plant in this part of Slovenia but I'm not sure it has a definitive English name there seem to be several.

En Route to Ljubelj Pass, Slovenia, 1st June 2001

Added on January 15th 2005, updated 24th March 2010