Both types of iris are hardy in zones 3 to 9, and both types bloom in spring. But bearded iris have the larger flowers, with the namesake fuzzy "beards" on the downward-facing fall petals. Siberian iris have smaller flowers without beards, and they typically bloom a little later than bearded iris. The foliage of the Siberian iris is grasslike, remaining attractive in the garden after the flowering period is done. Siberian iris is more tolerant of shade, and the tough fibrous root clumps do not need division as frequently as with the bearded iris.