diff --git a/homeassistant/components/portainer/strings.json b/homeassistant/components/portainer/strings.json
index 66416065435a..ac007499c9cf 100644
--- a/homeassistant/components/portainer/strings.json
+++ b/homeassistant/components/portainer/strings.json
@@ -262,7 +262,7 @@
           "name": "Endpoint"
         },
         "until": {
-          "description": "Prune images unused for at least this time duration in the past. If not provided, all unused images will be pruned.",
+          "description": "Only prune images created longer ago than this duration. If not provided, images of any age are pruned.",
           "name": "Until"
         }
       },