Alliteration (as well as consonance and occasional assonance) adds music, emphasis, and intensity to the poem. For example, listen to the /f/ alliteration that flows through the opening line, evoking the energy of that "force" flowing through the flower's stem:

The force that through the green fuse drives the flower

The pounding /d/ alliteration in lines 2-4 ("drives," "destroyer," "dumb") adds to the poem's powerful momentum, as does the general consonance of these lines (for example, "blasts the roots of trees"). Also note the abundance of /r/ alliteration and consonance both in this stanza ("force," "through," "green," "drives," and so on) and throughout the poem ("rocks," "red," "whirls," stirs," etc.). These back-of-the-throat sounds make the language seem rougher, echoing the harsh reality of time's relentless passage. Throughout the poem, repeated sounds make the language more intense, evoking the speaker's overwhelming sense of both amazement and isolation.

The poem's sounds also draw thematic connections between words. Take the similarity of "drives" and "dries," which reflects the link between creation (the way time drives things forward) and destruction (the way time dries up all life).

Finally, alliteration often brings the poem's striking imagery to life. For example:

• The /w/ alliteration of "whirls the water" evokes the whoosh and splash of swirling water.
• The hissing sibilance of "at the mountain spring the same mouth sucks" suggests the sound of time slurping from that spring. The fluid /l/ alliteration ("lips," "leech," "Love") and consonance ("fallen blood," "Shall calm") in lines 16-18 work similarly, evoking the sounds time makes as it gulps from "the fountain head."
• The crisp /t/ alliteration of "time has ticked" brings to mind the ticking of a clock.