Lady who Alfred Tennyson asked to 'come into the garden' (4)
I believe the answer is:
maud
(Other definitions for maud that I've seen before include "Come into the garden, - (Tennyson)" , "Tennyson poem" , "Old song: ''Come into the garden . . . .''" , "Girl invited into the garden in song" , "Girl invited into garden (Tennyson)" .)