Four times the speaker calls out "Hey, mother," and four times nobody answers. That unanswered shout drives the whole poem. The speaker never says whether the son is lost, grown up and gone, or dead, and the poem is more haunting for leaving that open.
Look at the names the son is given: "son," "boy," "child," "baby." Each stanza steps further back in his life, as if the speaker were following the mother's memory down the years until it reaches the infant. The questions shrink as they go. The first is enormous, searching "on the moon - under the sun," while the last is domestic and small: "where did he sit?" The search starts across the sky and ends at a spot in a room.
The opening stanza also hides a pun. "Son" and "sun" are the same sound, and they sit at the two ends of the stanza, holding the "where, where" between them. The moon sits against the sun, so the hunt seems to cover everything the sky contains. The verb "hollering" gives the missing boy a loud, comic energy, which fits the epithets that follow. He is "the funny one," the one "you doted on," the one who "was wild (you said so)." That bracketed aside suggests the speaker is quoting the mother's own words back to her. The son is described only through what others said about him, a portrait made of family sayings. The poem doesn't reveal who is speaking. Judging by the text, it could be a sibling, or the son talking about his younger self, or a voice left behind after he has gone. The poem seems to prefer that ambiguity.
The strangest moment is "which of the flowers / is he?" The stanza is short and its rhyme falls away, as if the question has drifted off. If the boy has become a flower, the image can read as death, with the child returned to the earth. It can equally read as a child lost among the plants of a garden. The poem keeps both meanings alive. "Settle" works the same way in "didn't he / settle? Somewhere?" It can mean to calm down, to make a home, or to sink quietly, like dust. A mother who called her son wild would naturally wonder whether he calmed down, but the word carries heavier possibilities too.
Tense matters here. The first stanza asks "where is he hollering," in the present. The third asks "didn't he settle," in the past. The fourth mixes them: "where did he sit, / where does he sing." The speaker can't decide whether the boy belongs to now or to then, and that wavering is a quiet form of grief, or at least of longing.
The sound of the poem is deliberately childlike. The lines are short and speech-like, and the rhymes are the simple kind a nursery rhyme uses: "child" and "wild," then "sing" and "ring." "Dance in a ring" recalls children's circle games, so the boy is pictured at play, endlessly circling. The title, "Song Just So Long," plays on "so long" as a goodbye. A song lasts only so long, and so does a childhood. This is an inference, but the singing in the final stanza gives it support.
Then comes the last line, a single word: "Somewhere?" It already appeared inside the third stanza as a hopeful afterthought. Now it stands alone and has to do the work of an entire stanza. It offers comfort, because he must be in some place, and it also admits emptiness, because the place has no name. The question mark stays open, and the poem ends without an answer.
The poem is significant because it puts a heavy feeling inside a light form. The casual "Hey," the singsong rhymes and the playful pun on "son" and "sun" make it sound like a game, while the questions underneath are the ones a parent, or anyone who has lost track of someone, might struggle to ask. It never names the loss, and it trusts the reader to feel it from the gaps.