I sent my 8 yr old out to my garden to collect flowers for vases before Grandma arrived.
To my horror she cut my siberian buds off! They made for an interesting vase- unoppened buds! Anyway, we were all surprised to see them open in the vase over the next several days. They outlasted the ones cut in full bloom- however all iris blooms ( that I have) in general, are short lived inside or out in my humble opinion.
Karen

I've had great luck with Dutch Iris lasting a long time, seems like 5 days or so.

I use all my iris because right now they are one of the main flowers I have in bloom. I have all different shades and colors of siberian and bearded. It's nice to know that the siberian can be cut in bud, I usually make sure I cut a stem with one flower almost open and the other in bud. As with all iris's you just have to be willing to snap off the spent bloom as they go. The bearded have more blooms on the stem, so they just keep coming. With the 2 kinds together, and some nice filler, they still make a stunning bouquet. I put tansy foliage, (before the blooms come) solomons seal, or white bleeding heart (dicentra). With me being in a zone 5, I have to depend on perennials this time of the year or I'd have nothing. With the temperatures we've had, they are the only thing right now that is huge, lush and green and in bloom. The annuals are just sitting out in the field saying, "When is it going to warm up?"
Cheryl