I believe that many Iris are stimulated to flower by changes in day/ night length. Arilate species sometimes flower in the northern hemisphere Automn at the same time as they are flowering in the southern hemisphere Spring. It would be interesting to compare more exactly using comparable latitudes and various sections of the genus. Mary Barnard is about the toughest variant I have grown, Walter Butt is difficult to establish. I think that these forms are North African but I believe from the British Iris Society Species Group 'A Guide to Species Iris' that I unguicularis, in the wide sense, extends eastwards north of Georgia into southern Russia, -not quite sure of the climate there, but I know that some of the Black Sea coast is fairly mild. On Mon, Dec 3, 2012 at 5:02 PM, James Waddick <jwaddick@kc.rr.com> wrote: > > On Dec 3, 2012, at 10:42 AM, Jim McKenney wrote: > > > > > > > Iris unguicularis started to bloom here today, too. My Maryland garden > is at about the same latitude (39.0839) as Jim Waddick's place in Kansas > City, MO (39.0997) but he is USDA 5ish and I'm USDA 7. > Dear PBSers, > > None of these are listed as suited to my USDA zone so I am 'pushing > ' them somewhat. > >