Plant knowing about American casualty (7)
I believe the answer is:
cannery
'plant knowing about american casualty' is the definition.
'cannery' can be an answer for 'plant' (thesaurus). I am unsure of the 'knowing about american casualty' bit.
'knowing about american casualty' is the wordplay.
'knowing' becomes 'canny' (I've seen this before).
'about' indicates putting letters inside.
'american casualty' becomes 'er' (I can't explain this - if you can you should believe this answer much more).
'canny' going around 'er' is 'CANNERY'.
Can you help me to learn more?
(Other definitions for cannery that I've seen before include "Row in Monterey" , "Factory filling tins" , "Food container factory" .)