When to Plant Siberian Iris Roots
Plant your Siberian Iris in Spring after the threat of killing frost is over.
Plant your Siberian Iris in the Fall a few weeks before the soil freezes.
Where to Plant Siberian Iris Roots
Siberian irises thrive in full sun conditions and in well-drained soil. Soggy soil will promote root rot. These perennials will eventually develop into large blooming clumps over a few years so allow a space 15-20" across for when your irises mature. Siberian irises do best in soil that has some humus. With that in mind, feel free to add some compost, decomposed manure or leaf mold if your soil is lean or sandy side.
How to Plant Siberian Iris Roots
These plants can sometimes struggle in the hot, dry climates. Siberian irises also do well in somewhat acidic soils although this is not a requirement for success. Install each plant, with the roots fanned slightly and pointing downwards, into a hole 3-5" deep. The point where the fan and the roots join should be 1-2" below soil level. Keep soil moist, but not soggy, while plants are establishing. A mulch of organic material helps keep Siberian iris roots cool and the surrounding soil slightly moist.
How to Care for Siberian Iris
At the end of the season, trim out any seed pods that may have formed. If the seed should set, the resulting plants are typically unlike the parents. Iris foliage should be trimmed to 2" in late fall.