The indeterminate but rare and beautiful nature of the flower ‘as May never bore' seems to contrast with the mundane ‘prettiness' of the rose-tree. This serves to highlight both the speaker's loss and the overblown self-esteem of his beloved.
The language of the first stanza could be seen as a little hackneyed. ‘Such a flower as May never bore' and ‘passed the sweet flower o'er', both read like typical lines from contemporary popular verse. ‘Pretty', too, is rather a well-worn adjective. This suggests that the speaker is conventional and mundane in his thinking and lifestyle, lacking the awareness to respond to life's chances.