Iris soft rot: how to spot, prevent and treat it disease
How do you spot iris soft rot?
The rhizome softens into a mushy mass and smells foul. The fan of leaves yellows from the outside in and pulls away from the rhizome at a tug.
How do you prevent iris soft rot?
The rhizome has to lie shallow, with its upper side at the surface and not covered by mulch, because buried and wet is what the rot needs. Remove yellow leaves as they appear, clear all foliage and debris in autumn, and keep fertiliser off the rhizome and low in nitrogen.
What works against iris soft rot?
Cut the affected part of the rhizome back to healthy tissue and take it out of the garden. Clean the knife between cuts. For the home garden there is no product.
Which plant gets iris soft rot? 1
Ornamentals 1
Sources: Clemson Cooperative Extension, University of Illinois Extension
Checked on 17 August 2026.