How to divide iris rhizomes

Do it:

Jul, Aug

Takes just:

30 minutes

Irises can become congested over time, which tends to inhibit flowering. This can be remedied by lifting and dividing their rhizomes to give them a little more space. Wait until flowering is over before dividing the iris clump, discarding any old, woody rhizomes and replanting only young, healthy plants into freshly-prepared soil.

You will need

  • Irises
  • Garden fork
  • Sharp knife
  • Trowel


Use a fork to dig up a congested clump of irises. Ease the plants from the soil, taking care not to spike the rhizomes.

Pull the congested rhizomes apart by hand, or cut them with a knife. Choose healthy pieces with leaves and discard old, woody sections.

Newly-planted rhizomes are vulnerable to wind rock, so it's a good idea to reduce the leaves by half. Use a sharp knife to trim them.

Replant healthy rhizomes about 12cm apart with the leaves facing towards the sun. Make a shallow hole and half bury the rhizome, giving it a firm push to bed it in - they like to bake in the sun, so don't bury them too deep.


It's a good idea to lift and divide clumps of irises every three years.

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