Iris germanica: How to Propagate Them?

When to divide irises?

Division should be carried out after flowering, when the plant is dormant (foliage turning yellow), between July and October. We recommend repeating this process every four years.

Equipment needed to divide your irises

• Spade or digging fork
• Secateurs or sharp knife
• Gardening gloves

How to divide irises?

• Start by preparing the ground where you’ll plant your irises. Preferably choose a spot where irises haven’t been grown before. Using an aeration fork or a spade, loosen the soil to a depth of 10 cm, incorporating coarse sand or gravel if your soil is heavy. Germanica irises need very well-draining soil!
• Lift the clumps with a garden fork, taking care not to damage the rhizomes.
• Remove excess soil from around the roots.
• Then, cut segments with roots and leaves, taking them from the outer part of the rhizome to get the youngest sections. Make clean cuts using a disinfected knife to prevent disease development. Only keep healthy, undamaged pieces.
• Trim the leaves to reduce their surface area to one third of their original length.
• Plant the rhizome segments 30 centimetres apart, leaving the top of the rhizome just showing. Replace the soil and firm gently.
• Finally, remember to water lightly to help them establish, ensuring beautiful blooms next year.

Also discover our video tips:

Tips and mistakes to avoid

Tips for Successful Propagation

Always plant the rhizomes shallowly to prevent rotting.

• Unlike other plants, iris needs its rhizome to remain partially exposed to sunlight.
• If buried too deeply, it risks rotting due to moisture.
• A good technique is to leave the upper half of the rhizome above the soil.

Divide every 3 to 5 years for abundant flowering.

• Over time, the iris clump becomes too dense, reducing its blooms.
• By dividing regularly (every 3 to 5 years), you ensure healthy renewal and prevent the centre of the clump from deteriorating.
• A good indicator it’s time to divide: fewer flowers and heavily overlapping rhizomes.

Label varieties to keep track.

• When propagating multiple varieties, it can be hard to distinguish them before flowering.
• A simple trick is to label each variety (plant marker in the soil or coloured ribbon on the leaves).
• You can also note iris colours and heights to organise your flowerbed effectively.