Dwarf Crested Iris: How To Care For A Dwarf Iris Plant - They’re one of the first harbingers of spring and a personal favorite of mine—miniature irises. These beautiful wildflowers make great additions to woodland gardens and borders. Get tips on growing them here.
This is a photo of Iris setosa 'Baby Blue' that I took at a botanical garden. It is a cultivar of arctic iris and very cold-hardy (to USDA zone 2). I don't grow this type, but my reticulated irises have been putting on growth throughout February, 2016: http://landscaping.about.com/od/floweringbulbs/p/dwarf-iris.htm
Iris reticulata & danfordiae 'Dwarf Iris Mixture' from Netherland Bulb Company - Dwarf Iris are famous for big flowers on tiny plants. Dwarf Iris are easy to grow in moist, well-drained soil in full sun to partial shade. Dwarf Iris will multiply and return year after year if left undisturbed.