Stand from 16 inches to 27.5 inches high, with their bloom season overlapping the Standard Dwarf Bearded and the TBs. Although the IBs show their dwarf ancestry in early bloom season and very interesting color patterns, they are large enough that their individual stalks may be nicely branched, forming an elegant bouquet. Some varieties are nicest in clumps, where they present a large amount of color (like the SDBs), while others are showiest in specimen plantings, where the stalks and individual blooms may be seen to best advantage.
Siberians are generally hybrids and have beardless blooms during May and June on 2’ vase-shaped foliage clumps. Both Spuria and Siberian have a culture different from the bearded varieties. (These are not included in the annual sale.)
Essentially small versions of the Tall Bearded in the same height range and bloom size as the intermediates, but blooming with the tall bearded varieties. Good BBs have round, ruffled petals that complement their small size.
This class is distinguished by daintiness and delicacy. Height from 16 inches to 27.5 inches. The blooms are smaller than on a BB and the stems are thin and wiry. An MTB clump looks like a cloud of butterflies. They are often called "Table Irises" because they are so well suited for arrangements.
Spuria, commonly called salt marsh or butterfly iris, are one of the tallest members of the iris family, reaching a height of 3’ and they bloom May-July. (These are not included in the annual sale.)
Some of the most useful garden plants, ranging in height from 8 inches to 16 inches. They begin their bloom as the MTBs are ending, still quite early in the iris season. They are best displayed in clumps where they give the effect of a "cushion" of individual blooms. The colors are nearly unlimited since the SDBs show all the different "spot patterns" of the miniatures, as well as the plicatas and pinks seen in the Tall Bearded.
Have stalks with a height of 27.5 inches and above, with branching and many buds. Each stalk, in itself, makes a stately arrangement in the garden or in a vase. In addition to a wide variety of colors and patterns, the TBs display other qualities (such as ruffling and lacing) more frequently than do the other classes.