A lot of money for an aromatic plant (4)
I believe the answer is:
mint
This clue is a double definition.
'a lot of money' is the first definition.
(I've seen this before)
'for an aromatic plant' is the second definition.
(I've seen this before)
(Other definitions for mint that I've seen before include "Place where coin money is made" , "Aromatic plant - make money" , "Fragrant herb" , "Where money coins are made" , "Make coin - herb" .)