Dear Dan and all, The Cal-Sibes or Calsibe are a valid and growing group of hybrids. They are formed by the cross between a Pacific Coast Native iris (PCN) (all of which have 40 chromosomes) and a Siberian Iris with 40 chromosomes, the Sinosiberian sub-group. There are dozens of these named cultivars. One of the most influential hybridizers is Dr. Tomas Tamberg ( see http://translate.google.com/translate/…) and others in the US such as Jean Witt and Lorena Reid come to mind. You can see quite a few at http://tamberg.homepage.t-online.de/homep9e.htm/ and scroll down to click to other pages including back crosses called 'Sibcal hybrids'. They do best in areas where the PCNs and Sino-siberian do well, but some of the hybrids are more widely adaptable than either parent. Try some. Jim W. -- Dr. James W. Waddick 8871 NW Brostrom Rd. Kansas City Missouri 64152-2711 USA Ph. 816-746-1949 Zone 5 Record low -23F Summer 100F +