Unusually as green as nettles (7)
I believe the answer is:
enrages
'nettles' is the definition.
'unusually as green' is the wordplay.
'unusually' is an anagram indicator.
'as'+'green'='asgreen'
'asgreen' is an anagram of 'ENRAGES'.
'as' acts as a link.
(Other definitions for enrages that I've seen before include "Infuriates" , "Incenses" , "As green changes it makes one angry" , "Makes furious" , "Works up" .)