The poem watches a girl going through puberty, seen from the outside by a speaker who isn't quite part of her experience. She is "overtaken by change," as if it has crept up on her, and she suffers it in the garden, a place that feels private and half-wild. The speaker doesn't tell us what he thinks outright. He simply reports what she says to him.
What she says is odd: the navy may land in the garden. It sounds like a child's logic, or a dream's, where a fleet arrives in a flowerbed. The final lines, about pen and ink beginning "to do business," are puzzling, and they can be read in different ways. Perhaps they hint at writing, at words taking on new weight, or at a world of adult dealings opening up. Either way, her body and her imagination seem to be shifting together.
The mood is quiet, tender and a little uncanny. The speaker seems gentle and watchful, amused but respectful, aware that something large is happening.