Glen Iris cultivated grape (8)
I believe the answer is:
riesling
'grape' is the definition.
(I know that Riesling is a type of grape)
'glen iris cultivated' is the wordplay.
'cultivated' indicates anagramming the letters.
'glen'+'iris'='gleniris'
'gleniris' anagrammed gives 'RIESLING'.
(Other definitions for riesling that I've seen before include "Fragrant white wine from the Rhine valley or from California" , "Sir Ingle makes wine from this grape" , "Dry white wine (German)" , "Gin riles the wine" , "Strange wine for Sir Ingle" .)