Plant opiate isn't distributed (10)
I believe the answer is:
poinsettia
'plant' is the definition.
The answer is an example.
'opiate isn't distributed' is the wordplay.
'distributed' indicates anagramming the letters.
'opiate'+'isnt'='opiateisnt'
'opiateisnt' with letters rearranged gives 'POINSETTIA'.
(Other definitions for poinsettia that I've seen before include "Ornamental house plant" , "bloom" , "House plant, popular at Christmas -- tiniest OAP (anag)" , "Flower popular at Christmas" , "American plant" .)