Tree cultivated by Anna (6)
I believe the answer is:
banyan
'tree' is the definition.
(banyan tree is a kind of tree)
'cultivated by anna' is the wordplay.
'cultivated' indicates an anagram.
'by'+'anna'='byanna'
'byanna' anagrammed gives 'BANYAN'.
(Other definitions for banyan that I've seen before include "Crush underfoot" , "Fig-tree found in th bay, Nan." , "Any ban for an Indian tree" , "Indian fig tree with self-rooting branches" , "Multi-trunked Indian tree" .)