The Siberian Iris is quickly gaining popularity for its ease of care, hardiness and ability to divide into clumps. There are many varieties of Siberian Irises, ranging in color from blues to pinks to white and yellow. The plants aren’t bothered much by pests and don’t have disease problems, which makes them perfect for beginning gardeners. The plant's grass-like foliage ranges in height from 12 to 40 inches, depending on variety, and the flowers are borne on tall stalks shooting from the foliage. Siberian Irises are hardy in USDA planting zones 4 through 9.
Choose a location in your landscape that has full sun to partial afternoon shade. Siberian Irises don’t mind being wet sometimes, but the location should not be constantly wet with pooling water. Plant in early spring or late summer.
Dig holes slightly larger than the size of a clump 18 inches apart. Or for a better display, use three or five clumps 2 to 4 inches apart, then another group 18 to 24 inches from them. The holes should be deep enough that the clumps are covered by 2 inches of soil.
Mix the dug-out soil with an equal part of compost. Lay the clumps in the holes and cover with the amended soil. Hand tamp down firmly.
Water the soil thoroughly after planting and again once a week through the growing season. Although the Siberian Iris is slightly drought resistant, watering more during the hot, dry summer will produce larger clumps and more blooms.
Cover the soil around the sprouts with a 2-inch-thick layer of mulch to keep in moisture and stop weeds from sprouting. The Irises will probably not flower the first season. This is normal and not a sign of a problem.
Apply 10-10-10 fertilizer the following spring and again in mid-summer. Follow the manufacturer’s directions on the amount to use.