Nature’s first green is gold,
Her hardest hue to hold.

The speaker opens the poem with these lines, which introduce the poem’s predominant theme of ephemerality. Here, the speaker is talking about the emergence of new life that comes with the arrival of spring. This is what they reference with the phrase, “Nature’s first green.” If, as the speaker says, “Nature’s first green is gold,” it means that the first buds of spring, though often thought of as being green in color, are in fact often gold. And since gold is the “hardest hue to hold,” the initial color quickly fades. This fading serves here as a symbol for the ephemeral nature of beauty.

Then leaf subsides to leaf.

This sentence marks the beginning of the poem’s second half (line 5). After detailing how the golden hue of a new bud soon changes to green, the speaker then references how that bud opens out to produce a flower that, in turn, lasts for only “an hour.” It is at this point that the speaker declares, “The leaf subsides to leaf.” Here, the speaker offers an image of the flower (i.e., Nature’s “early leaf” [line 3]) giving way to the leaves that will endure until autumn. However, the speaker’s phrasing is important, and particularly their use of the word “subsides.” This verb has strong connotations of lapse and decline. To subside means become less intense or vital, or else to diminish until gone. As these definitions indicate, subsiding involves a downward trajectory, which in this context conjures a melancholy image of leaves falling away forever.

So Eden sank to grief,
So dawn goes down to day.

The speaker continues to outline their pessimistic outlook in lines 6–7. The first line alludes to the story of the Garden of Eden. In the Bible, Adam and Eve commit the first sin by going against God’s decree not to eat from the Tree of Knowledge. Unable to quell their curiosity, they take an illicit piece of fruit from the Tree and eat it. Not only does this act lead to their expulsion from Eden, but it’s also the reason that, according to some denominations of Christianity, all humans are born in a state of original sin. In Christian theology, this story is generally referred to as the story of the Fall. And indeed, the speaker makes this allusion to emphasize the downward trajectory of decline. The speaker further underscores this downward trajectory in the following line. Just as Eden “sank” in a way that has caused perpetual grief, “So dawn goes down to day.” Here, the speaker employs an instance of paradox. Whereas we usually associate dawn with the rising of the sun, the speaker insists, counterintuitively, that the sun’s ascendence in the sky in fact brings dawn “down.” That is, full daylight brings an end to the golden hues of dawn.