The iris is one of the most popular and beautiful of garden flowers. With the wide range in plant type, size, and adaptation, there is an iris for almost any location. The standard iris, Japanese iris, Siberian, Spuria and yellow flag types are all suitable for Nebraska. By using an assortment of these types in a variety of sizes, iris bloom time can extend from early April through June.

Iris prefer a sunny planting location with good air circulation and well-drained soil. Sandy loam soil is best, but other soil types can be improved with organic matter to be suitable. One possibility for poor soil areas is to grow iris in raised beds, making soil improvement easier and improving drainage. Whether the plants are grown in a raised bed or not, work the soil to a depth of at least 10 inches.

In mid-July to early-September after the iris have bloomed the plants are dormant. This is the best time to plant iris and ensure adequate root growth and establishment before winter. This is also an excellent time to divide and transplant too-thick iris beds. Iris grow from an enlarged underground stem called a rhizome. All that is required to start a new plant is a few inches of firm, healthy rhizome with well-developed roots and at least one fan of leaves or a growing point.

Divide the plants any time after blooming is complete, but for best results divide in late summer and early fall. Before dividing the plants, cut the leaves to about one third of their full height. Dig up the entire clump of rhizomes and wash away the soil. This will make it easier to decide where to divide the rhizome and which, if any, parts need to be discarded. Smaller sections with only one fan of leaves will not need dividing again for three to five years, but will also be slower to produce a good show of flowers. Larger sections with two fans of leaves will produce flower more rapidly, but will also require division sooner.

Plant iris rhizomes just below the soil surface in a good soil. In heavier soil, plant with the rhizomes exposed slightly to prevent rotting. Roots should be buried to provide good anchorage. Form a cone or ridge of soil in the bottom of each hole; place the rhizome on top of the cone and spread the roots around the outside of the cone. Don’t allow the roots to clump together.

Newly planted iris, and sometimes even those in their second or third year of growth, need to be winter mulched. Use clean hay, straw, evergreen boughs or any other non-packing material.