I gave the ones I got from Spring Hill (very dried out) a good soak overnight. I only soaked the bottom roots. Then I planted them! They were a little slow but they did get new leaves on them before the snow fell. In your zone they should do fine. I added some H2O2 to the water to kill any bad stuff that might be on them. Some people use bleach! To harsh for me unless there is obvious problems.

Soaking them now - thank you Aquawise!

If you have any Liquid Seawood, I would add it to the water during your soaking period. I have found that it gives things a real boost.

Ms. Faith

Ms. Faith, I looked on Amazon, and they do carry Liquid Seaweed - will order some. Thanks for the tip!
Do you also use it to feed the plants after they have been planted?

Be cautious with water and fertilizer on tall bearded iris rhizomes, because they easily develop rot, which is encouraged by too much water and nitrogen. Planting dry rhizomes in good-draining soil is generally the safest way to get them going.
Renee

hosenemesis - you make a very good point. I check to make sure that there are no soft spots on the rizomes before soaking and then only soak for a couple of hours before planting in a good-draining soil. I water in the rizomes with the water that I soaked them in to make sure they get all the "goody" that they need. I like Liquid Seaweed because it is a very low nitrogen with lots of minerals,etc., that seem to give plants that extra healthy boost.