Iris Rot

Asked August 27, 2020, 10:51 AM EDT

I've had a bad outbreak of Iris (bearded) rot in three separate areas. I sprayed in the Spring but still got it. I've dug up the rotted plants. I don't intend to replant the areas with more iris. Is there a treatment I can use to kill the baterium that I assume is still in the soil? Are there plants/flowers that can safely be planted even if some of the bacteria is still present?

Howard County Maryland

3 Responses

Bacterial plant pathogens need wounds in plant tissue in order to infect them. For the Iris, these wounds are predominantly caused by Iris Borer when the larvae tunnels from the leaf into the rhizome underground. The borer does most of the damage in harming the rhizomes first, and the bacteria does the rest. Because of this, other plantings should not be at risk of infection. You do not need to treat the soil - which would not be successful in the long term in any case as microbes, including plenty of beneficial ones, are always re-colonizing soil - and should be able to plant any species suited to that site's conditions (light, drainage).


Miri, Thank you very much. Glenn