Bleeding inwardly Her maternal nectars into her own Coffin – (cradle of her offspring). (18-20)
Like the quote above, these lines move towards the end of the summer, when the poppy's petals are gone and the plant is doing other, more sinister work. The poem is gory about it, too – instead of a word like "transforming," we have "bleeding," and the process of becoming mother is linked entirely to the process of dying, all of which happens very quickly in this poem.
"She wore herself in her hair, in her day, and we could see nothing but her huge flop of petal, (22-23)
This first part of the eulogy for the poppy seems to be reflecting upon a kind of transience, especially with the "in her day" bit in there – the poppy did in fact have a day, but that day was only twenty-odd lines long. (We know, we know, the poppy flowers for a time period, lines are not a time period, but in this poem creates a world! So the poppy, for purposes of this kind of analysis, only exists in the poem. For 26 lines.) During that extremely brief period, the poppy was a riot of color and sensuality, so much so that those who looked upon her "could see nothing" but her.