Did flatter grass outside hospital already save odd characters? (8)

I believe the answer is:
wheedled
'did' is the definition.
Although both the answer and definition are past participle verbs, I don't understand how one could define the other.
'flatter grass outside hospital already save odd characters?' is the wordplay.
I cannot quite see how this works, but
'flatter' could be 'wheedle' and 'wheedle' is present in the answer.
A single letter 'd' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for wheedled that I've seen before include "Obtained by coaxing, persuaded" , "Obtained by flattery" , "Coaxed by flattery" , "Cajoled" .)
