Dividing Siberian Iris

Easy-care Siberian iris

Siberian irises are beautiful, spring-blooming perennials that are easy to care for but need division every few years to grow and look their best. You can go over a few Siberian iris division basics below then watch this video of Siberian iris collector Kris Jurik as she divides a clump that grew too large for its space.

How do I know if my Siberian iris needs division?

If your plant isn’t flowering as well as it used to and has developed an empty crater in the center, it’s time to divide. Depending on how quick-growing a variety is, you may need to do this every 3 to 5 years.

When to divide Siberian iris

The best time to divide is in fall. Early spring works just fine, too, but you might miss out on blooms that year. It’s simple to do but because Siberian iris roots are so dense, it can be hard work.

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How to divide Siberian iris

Dividing Siberian iris is pretty simple — the biggest challenge can be getting through the dense root system if you have a large plant.

1. Use a spade to dig the clump and lift it out of the ground.
2. Remove any dead roots or those without foliage with a pruning saw.
3. Make sure new divisions have at least three fans (or leaves).
4. Replant the new division at the same level it was growing.

If you don't want to dig the entire clump, you can also clean dead foliage and rhizomes out from the empty center and fill it in with soil. It may take a few years, but the plant will gradually grow back into that space and start flowering again.

If plants don't need division but you'd like to share some, simply put a spade in at the edge of the clump and dig out a piece to pass along. Fill the hole with soil.