Pure copper found in roots of drab meadow flower (9)
I believe the answer is:
buttercup
'meadow flower' is the definition.
(I've seen this before)
'pure copper found in roots of' is the wordplay.
'pure' becomes 'utter' (meaning complete or absolute).
'copper' becomes 'cu' (chemical symbol).
'found in' indicates putting letters inside.
'roots of' becomes 'bp' (I can't justify this - if you can you should believe this answer much more).
'utter'+'cu'='uttercu'
'uttercu' inserted inside 'bp' is 'BUTTERCUP'.
'drab' acts as a link.
This may not be right. It may belong to another bit of the clue.
(Other definitions for buttercup that I've seen before include "Common meadow flower" , "Common yellow meadow plant" , "Meadow flower poisonous to cattle" , "found in meadow" , "Bumboat woman" .)