Joy is hard to put into words, and Rossetti's answer in "A Birthday" is to let her speaker keep running out of comparisons. Her love has arrived, and the poem tries to measure the happiness that follows. Its central idea is that this feeling is too big for anything in nature to stand for it, so it calls for something grander: a throne, a ceremony, a celebration.
The first stanza opens with three similes, each beginning "My heart is like…". The repetition feels like someone counting treasures. Each image offers a different kind of happiness. A singing bird has a nest in a "water'd shoot," so there is sound, safety and fresh growth all at once. An apple-tree has "boughs … bent with thickset fruit," a fullness so heavy that the branches bow. Then comes a "rainbow shell / That paddles in a halcyon sea," which adds colour and calm. "Halcyon" comes from a legendary bird said to soothe the waves, and we still use it for peaceful, happy days. Water keeps seeping through these lines, in the watered shoot and then the sea, so everything feels nourished and nothing is dry.
Then the pattern breaks. "My heart is gladder than all these." The simile has failed, and the speaker says so. The rhymes show the same overflow. Lines two and four rhyme (shoot, fruit), but the last four lines all end on the long *ee* sound: tree, sea, these, me. It sounds like a feeling spilling past the usual limits of the pattern. The stanza closes on "me," an open, unguarded vowel, and the sentence it ends is oddly phrased: "my love is come to me." Saying "is come" rather than "has come" gives the line an old, almost biblical solemnity. It also makes the arrival feel present. Love hasn't just happened, it is here.
The rhythm helps. Most lines have eight syllables and four steady beats, so the poem moves with the easy lilt of the bird it begins with. Its vocabulary is mostly plain and short, which makes the occasional rich word stand out.
The second stanza changes mood completely. Similes give way to commands: "Raise me a dais," "Hang it," "Carve it," "Work it." The speaker sounds like a queen giving orders to unseen servants. What she orders is lavish: silk and down, "vair" (a luxurious fur), purple dyes, gold and silver. Here the images of the first stanza return, but transformed. The living fruit and birds are now doves, pomegranates and grapes carved or worked in precious metal, and the peacocks have "a hundred eyes." Nature has become ornament. This is the poem's quiet argument. Happiness this large wants to be made permanent and public, fixed in gold and displayed. "Raise me" also carries a double meaning, since love has already lifted her up.
The ending reworks the title. "The birthday of my life" is not an ordinary anniversary. It suggests that her real life begins on the day love arrives. The final line stumbles and restarts, "Is come, my love is come to me," as if she is too glad to get through it in one clean sentence. Repeating the news is the only way to take it in.
The poem is worth studying partly because of what it leaves out. We learn nothing about the beloved, not a name or a feature. All the attention goes to the speaker's inner state and how she wants it honoured. It also shows that joy can be written with as much craft as grief. The poem builds from modest natural similes to a royal ceremony in just sixteen lines, and the speaker's delight feels earned rather than merely announced.