Poems about grey hair usually end in a sigh. Dickinson's speaker notices "A little Snow" scattered in a friend's hair, counts the decades since "she and I had met and played," and then argues with Time instead of mourning. The central idea is that years can pile up on a person without ever taking possession of her. Time, the poem says, "had added not obtained."
That phrase carries the whole poem. "Added" is the language of arithmetic: Time is a clerk who keeps tallying years. "Obtained" is the language of conquest, of winning something for good. Time can do the first and not the second. The next line pushes the point with a military word, "Impregnable," which describes a fortress that no siege can break. Dickinson's inverted word order, "Impregnable the Rose," puts the defence first and the thing defended second, as if the Rose were hidden behind its own walls. Judging by the imagery, the Rose stands for the woman's living bloom, the part of her that the grey hair doesn't touch.
The imagery is a single metaphor stretched over eight lines: hair is winter, and the woman is summer. What makes it feel fresh is the tone. "A little Snow" and "here and there" are casual, almost fond, as if the speaker were noticing a stray thread on a sleeve. Then comes "Disseminated," a long Latinate word that sounds as though it belongs in a science lecture. It descends from a Latin verb for sowing seed, so there may be a faint echo of scattering. If so, the snow is sown but nothing takes root. The word is also comically grand for a few grey hairs, and that grandness suggests the speaker is half-teasing.
The vocabulary hardens in the last two lines. "Indelible" is a word from ink and writing: summer is written into her and cannot be rubbed out. "Obdurate" comes from a Latin word for hardness and has a stony sound. There is a nice irony in this, because snow is soft, yet the poem arms summer with the toughest words it can find. Meanwhile "met and played" sits quietly in the first stanza. It gives the friendship a light, youthful start, and it makes "Decade had gathered to Decade" weigh more. The line repeats its own noun, so the decades pile up in the sentence just as they do in the life.
The form changes between the two stanzas. The first runs on four lines of eight syllables each, brisk and even, like someone chatting. The second alternates eight and six syllables, a pattern familiar from hymns, and it ends on a firm rhyme between "Rose" and "Snows." The shift makes the second stanza sound like a declaration of belief. The rhyme in the first stanza is looser. "There" and "Hair" match cleanly, but "played" and "Decade" chime only if you lean on the last syllable of "Decade," which gives the word a little stumble. In the second stanza, "obtained" and "indelible" do not rhyme at all, and the poem is content to have only its second and fourth lines tied together.
The last word is "Snows," plural, where the singular "Snow" opened the poem. The enemy has multiplied, and the final dash leaves the sentence open, as if more winters are still to come. Yet the verdict has already been given: summer is too hard for them.
The poem is worth reading for how much it does in so few lines. It takes a familiar sadness, the ageing of someone we love, and turns it into praise. Dickinson's capitalised nouns make Snow, Time and Rose feel like characters in a small drama, with Time as an opponent who can only count. The poem is also affectionate, because it shows what the speaker sees in the friend beyond the grey hair. It admits that time passes but denies that time wins, and it makes that claim with both tenderness and a stubborn, stonelike vocabulary.