Sally's cultivated pear tree (8)
I believe the answer is:
repartee
'sally's' is the definition.
(thesaurus)
'cultivated pear tree' is the wordplay.
'cultivated' indicates anagramming the letters.
'pear'+'tree'='peartree'
'peartree' anagrammed gives 'REPARTEE'.
(Other definitions for repartee that I've seen before include "Witty exchanges" , "Comic dialogue" , "Banter - pear tree (anag)" , "Witty exchange" , "Witty comments" .)