Site Maria prepared for a herbaceous plant (9)
I believe the answer is:
artemisia
'herbaceous plant' is the definition.
(I've seen this before)
'site maria prepared' is the wordplay.
'prepared' indicates anagramming the letters.
'site'+'maria'='sitemaria'
'sitemaria' with letters rearranged gives 'ARTEMISIA'.
'for a' acts as a link.
(Other definitions for artemisia that I've seen before include "flavour of absinthe" , "Medicinal herb" , "Bitter tasting plant" , "species of plant" , "herbaceous plant" .)