The most popular and widely grown of the bearded irises are referred to as "tall bearded," but there are several other classes of bearded irises that can extend the bloom season and provide variety.
The earliest to bloom are the Miniature Dwarfs, commonly referred to as MDB's. They are up to 8 inches in height. One example is Keeno.
The next to bloom are the Standard Dwarf Bearded, or SDB's. They are 8-16 inches tall. There are many lovely SDB's.
The Intermediate Bearded, the IB's, bloom mid season and are 16-27 1/2 inches tall. Some recent award-winning IB's are:
Next are the Miniature Tall Bearded, or MTB's. They bloom mid-late season and often have thinner stems and more tailored flowers.
The Border Bearded, BB's, bloom late in the season and look just like the TB's, but they are shorter in stature -- 16 to 27 1/2 inches -- and have smaller flowers.
Then there are the popular Tall Bearded, TB's, with a late bloom season and over 27 1/2 inches tall. The varieties available are endless.
I grow all of the classes and often have irises bloom for up to 2 1/2 months. There are also rebloomers and beardless irises to add to your collection.