One word...Breathtaking. Is that one word or is that a compound?
Unlike Bearded Irises, Siberian Irises have woody roots just like Peonies. Plant them in a sunny spot and forget em. They will bloom and multiply for years. They can be divided, but not the way Bearded Irises are divided (where each tuber can be pulled away). It's not as easy and when you do divide them, they might not bloom the following year (similar to Peonies).
They are on the short side right now (since I divided them last year), but as the years progress they can be 4' tall and the plants have a "fountain grass look". They also make an excellent cut flower for a centerpieces if you want to get some quick flowers for the dinner table.
I'm going to have to pay another visit to my dear friend Barbara who I found on Craig's List last year. She sells her thinned plants on Craig's List and I bought these Siberian Irises and some pink Peones from her. For the price you're paying, you're getting a plant that has years of growth already which is priceless!