(TB) Tall Bearded
Tall Bearded iris have stalks with a height of 70 cm (27 1/2 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.
(LA) Louisiana
Louisiana Irises are a horticultural class of Iris that is equivalent to the botanical series Hexagonae. They range across the US Gulf Coast from Texas to Florida and up the Mississippi River to Iowa. They are called Louisiana Irises because the large diversity present in that state. They can be grown almost anywhere in the United States and even into Canada provided a few easy requirements for cultivation are met. The blooms are usually very wide petaled and open, showing brightly colored style-arms and sharp signal-crests. Some of the most spectacular Iris flowers are in plants of this group.
(SIB) Siberian
Siberians perform best with cooler conditions, regular moisture and a slightly acid soil. The blooms can be blue, purple, red-violet or yellow with newer cultivars in brown and orange shades, and can have a variety of forms from upright to flat and round. They are most attractive in established clumps that develop a bouquet effect and grow to a height of 2 to 4 feet, although some dwarf varieties are also available. Their grass-like foliage after bloom is one of their attractive garden features. They tend to bloom slightly later than the TBs. Cultivation of Siberians is easy.
(SPU) Spuria
Spurias are tall (2 to 5 feet in height) and elegant, and have very attractive foliage. The shape of the bloom often suggests orchids and the colors range from white and yellow through blue, wine and brown, often with bright yellow signals. This horticultural class is equivalent to the botanical Series Spuriae.