In a pickle, choose a flower for hearing (10)
I believe the answer is:
piccalilli
'in' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
I don't understand the rest of the clue.
(Other definitions for piccalilli that I've seen before include "Hot pickle" , "Chopped vegetables, mustard and hot spices" , "Spicy pickle" , "preserve with mustard" , "Mixed vegetables in a mustard sauce" .)