Siberian iris, also known as the beardless iris, is a low-maintenance iris that grows 2 to 4 feet tall on tall, slender stalks. These beardless blooms have grass-like, blue-green foliage that may turn a reddish, yellow or orange-brown color in the fall. Siberian irises bloom with a colorful display of small, delicate flowers in shades of blue, yellow, light purple and white in late spring. Siberian irises are hardy in zones three to nine, and do best in full sun. These plants aren't susceptible to the pests that may attack the bearded iris varieties. Cutting back the Siberian iris is done to stop seed pod production in the fall with minor pruning in the spring.
Remove the dead leaves of the plant and leave the Siberian iris stalks with the dark seed pods in place from summer throughout the winter.
If you do not want the seed pods to produce, cut back the iris's dead and withered blooms at the base of the plant in late fall, leaving 1 to 2 inches above the soil for next season's growth.
Cut back the yellowed or dead foliage in spring to promote new growth.