Beardless iris bloom after the TBs so they can extend the iris blooming season. Most beardless iris are native to Asia. In additional to species iris, the following groups can be grown in Minnesota gardens. Siberians are well represented in our gardens; the other groups have much to offer as well, but have specific cultural requirements. The following descriptions are paraphased from the ISA website.
1. Japanese Iris (JI) These irises produce spectacular flowers. Blooms are usually huge. Japanese hybridizers have worked with these irises for over 500 years. They bloom about a month after the TBs.
2. Louisiana Iris (LA) These iris are native to the American gulf coast. The blooms are usually very wide petaled and open with brightly colored style-arms and sharp signal-crests.
3. Siberian Iris (SIB) Siberians tend to bloom slightly later than the TBs. From 2 to 4 feet in height, their foliage is attractive all summer. They are available in a variety of colors and forms.
4. Spuria Iris (SPU) These are the tallest of the irises, up to 5 feet in height, with elegant blooms and attractive foliage. They are reminiscent of orchids.
5. Iris Cristata. Dwarf crested iris. Small, beardless iris native to the eastern U.S. can be grown in Minnesota. They prefer some shade and are lovely in a woodland or rock garden. These bloom earlier than other beardless iris.
6. Reticulatas. These irises bloom when the snow is melting in the spring. They are native to Eastern Turkey, Iran and the Caucasus Mountains. Alan McMurtrie in Canada has done hybridizing work with these irises and detailed information and many photos are available on his website.