Bloom times listed below are approximate and depend very much on the weather.
Standard Dwarf Bearded: Mid-March
Intermediate Bearded, Border Bearded and Miniature Tall Bearded: Early April
Tall Bearded Iris: Beginning of May (in warmer climates, possibly late April)
TIP: You can sort this list by "Height" to display it in order from the shortest Dwarf Iris to the tallest Tall Bearded Iris.