Written not long before his death from tuberculosis, Lawrence uses the Persephone myth as a frame for an erotic exploration of death.
In the Persephone myth, Hades (Pluto) lures the unsuspecting Persephone, a beautiful maiden, into the underworld to become his bride. Her mother, Demeter, the goddess of the harvest and fertility, ends up making a deal with Pluto that Persephone can divide her time between the surface of the earth and the underworld. While Persephone is away, Demeter is too deep in mourning to tend to the earth, so it goes into its dormant phase of the wintry months.
In "Bavarian Gentians," the speaker alludes to the Persephone myth when he longs for the dark blue gentian flower, whose deep color brings to mind the underworld, to become a torch lighting his way to this realm, which he calls "Pluto’s dark-blue daze." He alludes to Demeter and her "pale lamps," but then he turns his attention back to wanting to follow Persephone's path to the world of death, writing that he wishes to go
down the way Persephone goes, just now, in first-frosted September
to the sightless realm.
Yet rather than depict this as a frightening place, the speaker describes it as an erotic, desirable locale, where he imagines Pluto once again ravishing Persephone in his "deeper dark ... arms." The underworld, dark blue upon dark blue, is a spot where one can, like Persephone, experience the soft, piercing mysteries of sex.
By framing the poem around Persephone, Lawrence is able to depict the underworld, the place of death, as a heady realm of dark beauty and desire.