Siberian Iris Planting Guide

Planting Information

Choosing a Site

Siberian irises grow best in full sun. They also grow best in well drained soil; boggy soil will promote root rot. These perennial plants develop into large blooming clumps over a few years so allow a space 15-20" across for your mature irises.

Soil Prep

Moderately fertile soil to rich humusy soil works well for Siberian irises. If your soil is lean, add some compost, decomposed manure or other enriching amendment prior to planting. Siberian irises also do well in somewhat acidic soils although this is not a requirement for success.

When to Plant Siberian Irises

Plant Siberian irises outdoors in spring when frost danger has past and soil has warmed. These perennial plants can manage cold temperatures once establish, but during their settling in period they need protection from freezing.

How to Plant

Soaking your iris plants in a bucket of water for a few hours or overnight prior to planting helps reduce transplant stress. Do not allow the roots to dry out while transplanting. Plant iris rhizomes 1-2” deep. Refill around plant with soil, tap down to eliminate any big air pockets and water well to settle the soil around the roots. Keep soil moist, but not soggy, while plants are establishing.

Plant Siberian irises 12-18” apart.

During the Season

Siberian irises benefit from an application of a balanced fertilizer in early spring prior; 10-10-10 is good. A second application after flower helps strengthen plants and sets the stage for strong flowering the following spring. This isn’t necessary the first season, but is a good idea thereafter. Feel free to flowers to enjoy indoors. They aren’t long lasting but their textures, colors and patterns are gorgeous.

At Season's End

Trim out any seed pods that may have formed. Should the seed set, the resulting plants are typically unlike the parents. Iris foliage can provide protected overwintering sites for insect pests and should be trimmed to 2" in late fall.

Insider Tips

  1. A mulch of organic material helps keep Siberian iris roots cool and the surrounding soil slightly moist.
  2. The foliage of Siberian irises is slender and upright, providing a strong vertical accent in the garden. The grassy clumps turn to russets shade in autumn.
  3. Siberian iris produce seed pods that can be used in fresh or dried flower arrangements.
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Success Snapshot

Light: Full sun to partial sun

Soil: Average

Depth: Plant 2" below soil level

Water: Average, 1" per week

Uses: Perennial gardens, landscaping accents

Tip: Stop to appreciate the intricate blooms

GUIDE: Siberian Iris Planting Guide

They Start Out looking Like This: