Hi Sabina,

Ideally they should be planted in fall as your research shows, but they really only need several weeks of moist chilly weather in order to do well, so they'll be fine if you get them in the ground right now.

In many bitter-winter areas it would be pretty late since their ground is fully frozen and the iris don't want that long-term before they've had some cool moist weeks in order to make some roots. Yours should be fine as long as you're west of the mountains, which your zone indicates you are.

I love Dutch iris as they make such architectural blooms and foliage, and then just quickly disappear as summer heats up. I have bearded iris too and sometimes I just get tired of looking at their foliage all year long; at least the Dutch iris disappear when they're not earning their keep, lol.

Let us know how they do for you.
Happy gardening,
Grant

Thank you Grant for your advice.I put them in the ground and I will let you know ....

Happy Gardening!
Sabina