The Siberian iris is widely favored by gardeners because of its ease of growth. The plants can thrive in virtually any soil condition. According to the University of Minnesota, the Siberian iris grows from fleshy fibrous roots unlike other irises which grow from rhizomes. Their fibrous roots enable the Siberian iris to withstand wet and soggy conditions with ease. They grow well in shade and they are more resistant to pests than other irises. Siberian irises can be divided and transplanted in spring or late summer.
Choose a sunny site to transplant the Siberian iris into. The Siberian iris can thrive in shady locations, but they prefer sun. Make sure the soil is well drained for optimum growing conditions. The Siberian iris adores moist soil conditions and will tolerate being water logged but prefers simple moisture. The plants are also drought-tolerant when necessary.
Work a pitch fork around the Siberian iris plant that is to be transplanted and divided. Try to dig 6 inches out and around the clump. Work the dirt gently around the plant by sticking the pitchfork into the dirt and gently lifting. Once the plant is completely loose all the way around, take a garden trowel and gently work the plant and its root system out of the ground.
Rinse all the garden soil from the fleshy root system with a garden hose. Once you can clearly see the roots begin to pull them apart. If the plant is large and well established you will need a sharp knife to divide the fleshy root system. Each piece of the root system will make an individual plant once divided so make sure that each section offers enough root system for the Siberian iris to establish itself. Cut each root system down to the size of your hand. Each piece of root should ideally contain adequate roots and at least three leaves on the top.
Dig the holes for Siberian irises approximately 3 to 4 inches deep. Mix 50 percent peat moss with 50 percent garden soil for a nice planting medium for the transplanted Siberian iris to flourish in.
Plant each fibrous root 15 to 18 inches apart. Lay laterally into the ground with the roots facing down and the green plant life facing upwards. Gently press the soil and peat moss mixture down and around the roots. Water the plant thoroughly. Maintain moist conditions in order for the Siberian iris to begin establishing itself.