The poem begins by describing a mysterious "force" that moves through "the green fuse": a flower's stem. The word "fuse" makes it sound like this flower is about to ignite; this force seems electric, like a spark. That force, the speaker continues, moves up through the stem and "drives the flower," meaning that it powers or fuels it. Whatever this force is, it makes the flower bloom.

Enjambment pushes (one might say, "drives") the reader over the line break in a way that mirrors the movement of that force that travels up the flower's stem:

The force that through the green fuse drives the flower
Drives my green age [...]

This force doesn't just fuel the flower, readers learn in line 2: it also fuels the speaker's "green age," meaning it powers the speaker's youth. The whole sentence can thus be summed up as: "The force that makes the flower bloom also makes me young and energetic."

Note the use of repetition in lines 1-2:

The force that through the green fuse drives the flower
Drives my green age;

This is an example of chiasmus: the sentence's most important images follow an ABBA structure (green-drives-drives-green), as though the poem is circling back in on itself. This emphasizes the connection between the flower and the speaker, hammering home that both are equally subject to this "force."

The specific words that the poem repeats here are also thematically important:

• The color "green" symbolizes freshness and vitality. Both speaker and flower are in the fresh "bloom" of youth.
• The word "drives" conveys the relentless power of this "force" over the speaker and the flower. They are not driving but being driven, pushed forward.

The next line tells readers more about this force. While it makes both flowers and young people bloom, it also "blasts the roots of trees" and will ultimately become the speaker's "destroyer."

What creates things only to later destroy them? Time! The speaker is talking about the way that time makes things both grow and decay.

Dylan Thomas creates meaning not just through the literal meaning of the words he chooses, but also through the way the reader feels when they read them. Here, the rich, rhythmic sounds of the poem make it more intense and emotional. For example, these lines are thick with alliteration (force"/"fuse" "flower), assonance ("through"/"fuse"/roots"; "drives," "my), and consonance of /r/, /t/, /s/, and /z/ sounds:

The force that through the green fuse drives the flower
Drives my green age; that blasts the roots of trees
Is my destroyer.

The poem's meter adds to its momentum as well. Lines generally use iambic pentameter, meaning that they contain 10 syllables that follow an unstressed-stressed pattern (da-DUM). This creates a marching rhythm that pushes the poem forward.

However, Thomas isn't particularly strict with the meter. Here's line 1 for instance:

The force | that through | the green | fuse drives | the flow- | er

While the rhythm is clearly iambic overall, it contains inconsistencies: there's a spondee (two stressed syllables) in the fourth foot ("fuse drives") and an extra, unstressed syllable dangling at the end of the line. Such variations keep the poem from feeling overly stiff.

Also note that the third line of each quintain (or five-line stanza) is much shorter than the lines surrounding it, thus breaking up the poem's rhythm and calling readers' attention to certain words—in this case, the word "destroyer." Time may be the giver of life, but it is also the thing that takes it away.