Oops, I did it again. I know it has happened to almost everyone. You pick up a few irises at your local sale and set the bag aside for planting later. Or maybe a box arrived when you were busy and was misplaced. Out of sight, out of mind.
Then, on a late Fall day you stumble across them. Horrors, are they still alive? Do I dare look in the box? What do I do with them NOW!
If they are bearded iris then they are most likely fine. They are not happy by this time, though. Don't expect flowers next Spring, but there is an excellent chance you can save them. You have to plant them, right away, even though it's the wrong time of year. Don't wait until Spring as they will be even weaker by then.
They will sprout roots very quickly after planting as the soil is cool and moist this time of year. They will not have time to grow enough roots to withstand the rigors of the coming Winter without a little help. Fortunately, there is a very easy and reliable method to protect them through this precarious predicament.
The 'BRICK METHOD'
Plant the iris as you normally would in your climate. I have heavy clay so the rhizomes are just barely covered with soil. Then place a brick or flat rock immediately behind the fan on top of the rhizome. I usually leave the old foliage on until early Spring when I remove the brick. I have rarely lost an iris doing this unless it was actually dead by the time I found it.
Some people suggest a thorough soaking and a quick rinse in bleach water before planting but I haven't found that necessary. If you have a lot of irises to plant this way you can cover the rhizomes with a 2 x 4 board weighted at a few spots with bricks or stones.
This even works with beardless irises but must be modified a tad. After planting place a brick on either side of the clump, close to, but not covering the new fans of foliage.
This is one of the first things I remember learning after joining the Greater Kansas City Iris Society. Belonging to a local iris club is the best way to learn tips and tricks for growing irises in your area.