Answer: You can transplant your Siberian irises now and they shouldn't mind being moved. I always try to transplant my perennials when daytime temperatures remain below 80F but nighttimes are still above 50F. This way the plants won't have to deal with the heat while they are trying to re-establish their root systems, nor shiver in the cold. Late August or early September should be good times in your gardening region.
Best wishes with your new transplants!
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