The green plant looks like a Cattail, not an iris. I would say almost 100% that it is a Cattail plant.

How odd that it would appear in a container after three years! I guess when I divide the clump it will be apparent which is which?

I would take the whole iris and cattail out of the pot and look at the root system(s) the cattail will have a white rhizome that is probably in the process of filling the bottom of the pot - pull the iris plant away from the cattail and replant the variegated iris. The iris plant will have a darker colored rhizome/roots.

I grow some aquatic and wet growing plants here that have had cattails sprout in them - the seed travels on the wind - it doesn't take long for the seedlings to get big when given the right (wet and fertile) conditions.

it is not uncommon to have to divide variegated plants.. to maintain such ... in fact.. with many.. i would call it requisite ...

do you figure it came from the nursery with it ....

in the proper season.. you should probably bare root it.. and insure you only have the plant you want to repot ...

ken

Mine reverted -- is now a boring green.

When is the proper season? This is happening to mine -- reverting, I mean.