Charge when flower pruned in private borders (9)
I believe the answer is:
prosecute
'charge' is the definition.
(thesaurus)
'pruned in private borders' is the wordplay.
'pruned' becomes 'rosecut' (I can't explain this - if you can you should give a lot more credence to this answer).
'in' indicates putting letters inside.
'borders' says to hollow out the word (remove centre letters) (only the edge or border letters remain).
'private' with its middle taken out is 'pe'.
'rosecut' going into 'pe' is 'PROSECUTE'.
'when flower' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for prosecute that I've seen before include "Sue" , "Bring before a criminal court" , "Pursue" , "Take legal action" , "Practise" .)