Robert Frost's poem "A Late Night Walk" is a lyric poem of the variation called ballad. Lyric poems come in several varieties including sonnets and ballads. Each variety of lyric poem has its own defining structure although poets can, and do, vary conventional structures to suit their purposes.
The definitive ballad structure typically has quatrain stanzas of four verses (i.e. lines) each. A quatrain is defined as a stanza with four lines. The verses alternate in meter. The meter alternations are between tetrameter (four feet of rhythmic pattern) and trimeter (three feet of rhythmic pattern). The standard rhythmic pattern in ballads is iambic (^ /), or an unstressed followed by a stressed syllable. The definitive rhyme scheme for a lyrical ballad is a b c b, in which the second and fourth lines rhyme. How does Frost's poem compare to the definitive ballad structure?
Frost's poem has four quatrain stanzas. Frost's verses alternate between iambic tetrameter ("When^ I' / go^ up' / through_the^ mow' / -ing^ field',") and iambic trimeter ("The head' / -less af' / -ter -math',"). It is important to note that scansion reveals an elision of syllables in several lines, for instance, lines one, three and four in the first stanza. Scansion is the act of reading and marking verses for meter and rhythm. Elision is the omitting and blending of syllables or words into one as in "through_the" to produce one scanned beat instead of two. Frost's meter does in fact fit definitive ballad metrical structure.
Frost's rhyme scheme in the first stanza is a b c b: field, math, dew, path. The second, third and fourth stanzas follow suit with d e f e g h i h j k l k. Each stanza starts with a fresh stanzaic rhyme scheme with no verse in a subsequent stanza referring back to a previous rhyme. Frost's rhyme scheme does fit definitive ballad rhyme structure.
The content of this lyrical ballad narrative is very interesting. The third stanza says the poetic speaker is "not far from" where he went "forth," or began, his walk. Yet the opening line has him going "up through the mowing field." In other words, we join him on the last half, or the return half, of his late walk. "Up through" implies a modest rise in the ground level or could simply be a conversational colloquial usage meaning to go back where one started.
"The headless aftermath" of the mowing field conjures up a mental image not common to us anymore. When farmers mow their grass, or hay, fields these days, mower machines automatically spit out little bundles or rolls of hay. The speaker is walking through hay cut with a scythe and allowed to drop to the ground to be gathered later into bundles or stacks. It is this collection of mown and left hay that blocks the garden path like thatch on a roof.
While the speaker is definitely sad to see summer go (the "whir of sober birds," the tree that "stands bare," "sadder than any words") in the cold autumn days in which he is walking, the poem nonetheless ends with charm and affection instead of despondency. He picks the last touch of blue to "carry to" his beloved.
Let's start with the mechanics. The poem is written in quatrains, or four-line stanzas, in which three-beat and four-beat lines alternate. This is a traditional form; see the Wikipedia reference below.
The rhyme scheme is a, b, c, b: only the second and fourth lines of each stanza rhyme.
The mood is rather somber, reflecting the season, which is autumn: whence the "late walk". In stanza I you have
The headless aftermath
of the harvest, suggesting death that happened a while ago. In stanza II there are
In stanza III you have the tree with only one leaf left hanging, which falls as the poet passes.
Stanza IV changes the mood considerably: the poet picks "the last remaining aster flower": although faded, it is his gift of love to somebody who appears in the last word of the last line.
Here are some other interesting devices the poet uses:
In stanza I, "Smooth-laid like thatch with the heavy dew" is rather heavy itself with many accented feet. It suggests the poet is wading through this deep thatch of straw.
Stanza II uses alliteration: "garden ground", and "withered weeds". Alliteration was used in some of the old epics as a kind of rhyme, where the beginnings of the words, rather than their endings, would match. Again, "Up from the tangle of whithered weeds" has an abundance of strong feet which tend to tangle your tongue.
Stanza III user personification: the tree "stands", a leaf "lingers", is "disturbed", and "comes down". Here this device draws immediate attention to the tree and the leaf, while the wall fades into background. Again we have alliteration: "beside", "bare", and "brown"; also "disturbed" and "doubt". Also internal rhyme -- which may be accidental -- of "not" with "thought". Come to think of it, some internal alliteration: "s" in "beside","stands", "disturbed", "comes" and "softly".
Stanza IV uses alliteration again: "far", "from", "forth", "faded", and "flower" (which contrasts with, and sets aglow, the sound of "aster").
In each stanza the third line seems to stand out, which helps to point out the significance of "the last remaining aster flower".
So: with all this analysis, we've chopped the poem into tiny bits. But now read the poem again, as a whole: savor its goodness, and maybe let all this analysis add just a hint of additional sparkle.