Answer: The flowers of your iris should be finished for the season so you can dig the rhizomes up, cut the foliage down by two-thirds, pack them in dry sawdust or peat moss and place them in cardboard boxes just before the moving truck leaves the driveway. If you have to store them in cardboard boxes for a day or two before or after the move, use the ventilated boxes that produce comes in (ask at your local grocery store) and after packing your iris rhizomes into them, keep the boxes in a cool, shady spot.
Dahlias can be dug and packed in the same manner.
Best wishes with your move!
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