Dutch iris are bulbs. If they like your climate zone they will increase by themselves (like daffodils). If you have some bulb food, bonemeal or superphosphate dig it in below their planting depth. After flowering allow the foliage to turn yellow before removing.

Bearded iris are most often discussed here. They, as well as beardless iris, may be divided.

Thanks iris Gal. So i can just split the root/bulb in half...

Just want to make sure there isn't a particular way....so i don't kill it. One iris in the garden is better than 2 in the trash.

Absolutely not.

Yours is a bulbous iris. It will increase if it is happy all by itself. RE-READ my answer please.

Professionals do use other propagation methods for bulbs which most home gardeners do NOT.

I didn't get into discussing dutch iris, but the can be divided like most perennials, actually they grow like weeds if they are in a good soil and they don't need much mositure but I accidentally dropped some bulbs in my creek and wow did they spread.

Here is a link that might be useful: Propagating Perennials

Often Dutch are planted sooner, as many are up now and getting ready to bloom early. You would not want to hold your bulbs to plant later, it would be best to plant asap, and you might want to consider putting some in pots, they'd show pretty in pots, and then you could put them in the ground late next fall.