Reshaping formal yew shrub (9)
I believe the answer is:
mayflower
'shrub' is the definition.
(mayflower is a kind of shrub)
'reshaping formal yew' is the wordplay.
'reshaping' indicates anagramming the letters (I've seen this in other clues).
'formal'+'yew'='formalyew'
'formalyew' anagrammed gives 'MAYFLOWER'.
(Other definitions for mayflower that I've seen before include "Tree" , "emigrants' vessel?" , "Famous Pilgrim ship" , "Ship on which the Pilgrim Fathers sailed to America" , "Pilgrim Fathers' vessel" .)