A man is offered a rare, beautiful flower—one that May itself never produced—but he turns it down, saying he already has a pretty rose tree. He then goes to tend his rose with care, day and night. Yet instead of gratitude, she meets him with jealousy and turns away. In the end, her thorns become his only delight.
That’s the whole story in four crisp stanzas, but the feeling lingers. The speaker sounds devoted yet quietly frustrated. He did the “right” thing by staying loyal, and what did he get? A lover who punishes him for another’s interest, and a relationship reduced to painful thorns. That word “delight” is bitterly ironic—it suggests he has learned to find pleasure in the hurt, or maybe it’s all he has left. The mood is a mix of disappointment and dark acceptance. Blake captures the trap of possessive love: you can reject temptation, but if the one you’re committed to is ruled by jealousy, you’ll still end up wounded.