diff --git a/cylc/flow/scripts/trigger.py b/cylc/flow/scripts/trigger.py
index 5cf64fd84d..2d353b4d8c 100755
--- a/cylc/flow/scripts/trigger.py
+++ b/cylc/flow/scripts/trigger.py
@@ -27,7 +27,8 @@
 running) at once. They release tasks to run when their active task count
 drops below the queue limit.
 
-Attempts to trigger active (submitted, running) tasks will be ignored.
+Attempts to trigger active (preparing, submitted, running)
+tasks will be ignored.
 
 Examples:
   # trigger task foo in cycle 1234 in test