Species: Allium christophii.
This flower head was 8" across when I took this photo on 3.7 2010. With all the rain we have had it has opened out even further but it waves about so much none of the photos I took today came out. I reckon it is getting on for 10" across and approx. 7.5" top to bottom. It is 30" in height. I have 2 this size and several slightly smaller. This is another of my bargain bulbs which were planted very late .