How to Grow Siberian Iris

Siberian Iris bee plant with purple flowers

The Spruce / Evgeniya Vlasova

In This Article

Siberian iris is not as showy as many other types of irises are, but it makes up for this by being easy to grow and more drought-tolerant. Bees and butterflies are drawn to it, but deer tend not to eat it, and the plant is also resistant to rabbits. So you will not have to spend a lot of time on pest control when growing Siberian iris.

While not large by iris standards, the flowers are colorful and have a graceful shape. An advantage the Siberian iris has over the bearded iris (Iris germanica), for example, is that its foliage, which forms vase-shaped clumps, remains attractive after the blooming period is over. The leaves are narrow and bluish-green.

Siberian iris grows from underground rhizomes. The rhizomes spread out beneath the surface of the soil to form a network that holds back the soil during rainstorms. This feature makes the plant useful in erosion control.

Since Siberian iris does spread, be careful about picking a place in which to grow it. You would not want to grow it in or around a flower border where it would be expected to behave well with its companion plants. It does not play well with others, and, as it spreads, you would find yourself constantly removing it from where it does not belong.

  Botanical Name Iris siberica
  Common Name Siberian iris
  Plant Type Herbaceous perennial
  Mature Size 3 to 4 feet tall, with a spread of 2.5 to 3 feet
  Sun Exposure Full sun to partial shade
  Soil Type Rich and well-drained, with average moisture
  Soil pH Neutral to slightly acidic
  Bloom Time May
  Flower Color Blue, violet, white, or purple
  Hardiness Zones 3 to 9
  Native Area Northern Asia.

Siberian Iris Care

While tolerant of shade at the northern end of its range, the Siberian iris does not flower well in excessive shade; too much will cause the leaves to flop over. Keep the ground consistently moist throughout the spring and into early summer. Most gardeners deadhead the plants to promote further blooming, but some abstain from this so as to retain the seed pods for winter interest.

Siberian iris banish misfortune plant with purple and yellow flowers

The Spruce / Evgeniya Vlasova

Siberian iris sultan's ruby plant with violet and yellow flowers

The Spruce / Evgeniya Vlasova

Siberian iris purple mere plant with purple and yellow flowers

The Spruce / Evgeniya Vlasova

Siberian iris white amber plant with yellow and white flowers

The Spruce / Evgeniya Vlasova

Siberian iris how audacious' plant with violet and yellow flowers

The Spruce / Evgeniya Vlasova

Light

Siberian iris will flower best if grown in full sun (in the North), but the plant tolerates partial shade. In the South, it prefers partial shade, especially if you will not be able to water it regularly during the summer.

Soil

The main requirement Siberian Iris has in terms of soil is that it should drain well. Poor drainage can result in root rot. That said, this plant is remarkably tolerant of soil conditions, and can usually even handle relatively wet soil.

Water

Since the Siberian iris is susceptible to crown rot, do not intentionally saturate its soil. Light, regular watering is preferable.

Fertilizer

Fertilize the Siberian iris every spring with compost.

Siberian Iris Varieties

In terms of size and shape, the different varieties of Siberian iris do not diverge greatly from each other. But hardiness does vary, and you have a choice between three or four flower colors.

  • 'Caesar's Brother': Purple flowers; zones 3 to 8
  • 'Snow Queen': White and yellow flowers; zones 5 to 8
  • 'Butter and Sugar': White and yellow flowers; zones 3 to 8

Propagating Siberian Iris

The maintenance involved in growing Siberian iris stems mainly from the fact that the plant grows from rhizomes, which allow it to spread.

Divide Siberian iris when the center of the crown starts to feel woody rather than pliant. You will also get a visual signal that this is happening: The plant will start to peter out. This will be especially evident when you have multiple plants, as overcrowding will occur and each plant will sap the strength out of its neighbors.

Dividing the plants like this will not only increase your supply but it can re-invigorate the original speciment.

Plant the rhizomes for this perennial in spring (or in fall, in the South), install them 1 to 2 inches deep, and space them 1 to 2 feet apart. Siberian iris spreads quickly, so be sure that you are planting it in a spot where it has room to grow.