How does John Keats use imagery in La Belle Dame sans Merci?

In the third stanza, it is not the appearance of nature, but rather, the spiritual condition of the knight-at-arms, which has been the theme of the first halves of the first two stanzas. By this absorption of the knight into the structural pattern of the natural imagery, the movement from a suggested but unstated relationship of man and nature in stanza one to an implied interrelationship in stanza two has now been completed. In the third stanza the two terms are organically integrated, and human values and natural images have been molded into interchangeable expressions: the lily and the rose are present in the knight's countenance, and his withering is theirs.