Marvell opens with an instruction to look: "See with what simplicity / This Nimph begins her golden daies!" A small girl lies in the grass, gives names to the wilder flowers, and saves her real attention for the roses, telling them "What Colour best becomes them, and what Smell." It is a charming picture, and for a stanza the poem seems content to stay one. But the title hints at more. A "prospect" is a view, and also an outlook on the future. Marvell plays on both senses: while watching the child in the garden, he is looking ahead to the woman she will become.
That forward glance takes over the second and third stanzas, and the language turns military. One day she will make "wanton Love" fear her, and his "Bow" will be "broke" and his "Ensigns torn." Her eyes become a conquering army whose "glancing wheels" drive "In Triumph over Hearts that strive, / And them that yield but more despise." The speaker, sensibly, wants to "compound" and "parley," to settle terms before the attack begins, and asks only to watch her "Glories from some Shade." There is real wit in treating a child at play as an invading power. Some modern readers may also find it uneasy, since the adult gaze is already turning her into a figure for grown-up desire. The poem seems half aware of this, which perhaps explains why it soon changes direction.
In the fourth stanza the girl is given a gardener's authority over nature. She is asked to "Reform the errours of the Spring": to give tulips a share of sweetness "seeing they are fair," and to disarm the roses of their thorns. Each request wishes beauty could come without a cost. Then the list ends with "But most procure / That Violets may a longer Age endure." The word "most" quietly reveals what the speaker really cares about, which is not beauty but how long it lasts.
The last stanza makes that worry explicit. "Gather the Flow'rs, but spare the Buds" sounds like a gardener's tip, but the girl is herself a bud, "young beauty of the Woods." If she picks too carelessly, Flora, the goddess of flowers, may be angry at her "crime" and make "th' Example Yours." The final line, "Nip in the blossome all our hopes and Thee," holds back its real subject until the last word. The pronoun "our" shows that her life matters to more than herself. The child who was going to conquer Love ends the poem as something that can be nipped by frost.
The form helps this change of mood. Each of the five stanzas has the same shape: six lines of mostly eight syllables, then a short four-syllable line, then a ten-syllable line that rhymes with it. The pairs are "tell/Smell," "can/Man," "laid/Shade," "procure/endure" and "see/Thee." The short line works like a caught breath and the long one lets it out. The light, quick lines suit a child's play, so when the last line stretches out it feels heavier. The rhyme of "see" and "Thee" at the very end leaves the girl as the last thing we hear.
The poem matters because it keeps changing its mind about what it is. It starts as a compliment, becomes a mock-heroic conquest, and ends as something close to an elegy, all within forty lines and without raising its voice. Marvell's "To His Coy Mistress" famously urges a woman to seize the moment. Here the advice is the opposite: be gentle with time, and let the bud ripen. The garden, usually a place of innocence, turns out to be a place where innocence is at risk, and the speaker's tenderness is mixed with fear for the girl.