As most of my irises are new, I can tell you of a few, even though only planted last year, had a long bloom time. I am not saying, however, that they were well-branched, or had 7 or 8 buds...maybe next year. Golden Panther has several flowers per stalk, but does not bloom over a long period of time. (It could be because it is blooming in part shade.)
The exception to that last statement was Thornbird. But the reason might be that what was sent to me was a very large rhizome with several increases. It was a huge clump and bloomed over a long period of time. Many people on this forum have reported that this iris is vigorous in many areas of the country. Still, it did not have 7 or 8 buds per stalk, maybe next year.
Thornbird May 22 - June 3
Samurai Warrior May 12 - May 29
Picture Bouquet May 13 - June 4
Pink Unicorn May 18 - June 7
Awesome Alex May 24 - June 6
Trillion May 23 - June 3
These bloomed early to late.
Of the ones I have that are well-established,
I have two that bloom every year and are long-blooming:
Beverly Sills May 18 - June 4
Harvest of Memories May 19 - June 2
These are all well-branched, but since they are in part shade, not 7 or 8 blooms per stalk, usually just 3 or 4.
I had to look at my photographic records, and I will have to amend, in some cases, my paper records. (It is handy to have a smartphone. I haven't used my camera for quite a while.)
Edited to add Chasing Rainbows. It just started blooming on May 29th. It has huge, substantial blooms, and 4 buds per socket. The stalks are thick and sturdy. I am going to have to move it to the top of my list! Here is a picture that I just took.
to the iris forum MarJoe 
