Olson starts with a lowercase preposition, as though we have walked into the middle of someone's thought: "from the sunsets / to the rubbish on the Harbor bottom." That opening range holds the poem's whole argument. A town stretches from the most postcard-worthy thing it owns to the most unmentionable, and a poem that wants to be honest about Gloucester has to cover the full distance. The title makes a promise of its own. "Part of the Flower of Gloucester" suggests a bloom, or a fragment of one, yet what we get is not petals but bubbles of gas.
The gap between that promise and the delivery gives the poem its dry humour and its force. One could read the bubbles as grim little flowers, opening at the surface and breaking, though the poem never says so. It simply tells us to "watch them break." The diction does the work. Most words are plain and physical: "rubbish," "bubbles," "surface," "smell." Then comes "putrefaction," a heavy, clinical, Latinate word that sits in the middle of the sentence like something dredged up. Its clipped p, t and f sounds are close to the sound of what it names. Those f sounds recur through the passage ("fermenting," "formed," "from," "putrefaction"), so the rot seems to bubble up through the language itself. The word "from" also appears twice, once for the sunsets and once for the gas. Beauty and decay are both said to come *from* something, as if they share a source.
The poem is one unpunctuated sentence, and the syntax is slightly loose in a way that feels like speech. "Fermenting so bubbles" has no pause where a reader might expect one, so we have to supply the joints ourselves. "Keep coming up" is in the continuous present, which tells us this is not a single event but a process that never stops, like the bubbles themselves. The line breaks cut mid-phrase and mid-name ("the Inner / Harbor"), so the eye keeps being pushed forward. There is no rhyme and no regular meter. Instead the lines run roughly as long as a breath of talk. Olson is famous for arguing that a poem's line should follow the speaker's breath, and you can feel that idea at work in how the longer lines tumble and the short ones, like "which is true," stop to make a point.
That phrase is the poem's hinge. Until then the poem has been describing and addressing us: "you watch them break / on the surface and imagine the odor." Then, in a flat, almost argumentative aside, the speaker insists that the imagined smell is accurate. It's true "at low-tide that you can't stand the smell." Low tide matters here, because the water pulls back and the harbor can no longer hide what it holds. The sentence is grammatically a little clumsy, and it sounds like a local correcting an outsider.
The last two lines make that outsider-versus-local divide explicit. The smell is unbearable "if you live with the Harbor Cove or the Inner / Harbor to your side." The capitalised names ground the poem in real water, and "to your side" makes the harbor a neighbour rather than a view. A visitor might see only the sunsets from the first line. The resident gets the whole package. The poem stops without a full stop, on that conditional, so the smell is left hanging.
The poem's significance lies in this refusal to prettify. Olson's work is closely tied to Gloucester, Massachusetts, and this short piece suggests what that attachment looked like. It was not postcard affection but a willingness to include the stink. Knowing a place, the poem implies, means knowing what it smells like at low tide, and a writer who leaves that out is only describing scenery. By placing the sunsets and the putrefaction in one breath, Olson makes the town seem more real and, oddly, more worth loving.