I would move it to an area where it would receive less sun earlier in the fall and therefore think fall is coming earlier. That has worked for me on a few of them. If diminished light is the trigger that makes an iris rebloom this will work. I am moving my re's to an area where the shade from the house will begin to give them less sun, and therefore cooler temps, in late August and they have actually had blooms in late September and October. I am going to keep working on this project next summer and see if I can get more of the re's to bloom earlier. Last year I tented a lot of irises and that not only was a lot of work but looked quite ugly in the garden.
