Welcome, Tisha. Being in a similar climate, Leon has good advice.
Since it sounds like you've had the iris for a while, I'd consider doing some non-digging thinning per this article - if Leon agrees.
https://garden.org/ideas/view/...
What you want to do is cut out the non-productive old rhizomes -
NOT any "mothers" with growing increases.
If now is not the time to do it (because it is getting late), then you should consider doing it early next spring (which is what I think the author, Kent, did). You can then do any real dividing needed next summer.
(Makes note to self... get out the Hori Hori knife...)
