A furry peach ke momo was a slang term for female genitalia, as the organs were believed to resemble the fruit.

A euphemistic reference to the onset of menstruation. In modern Japanese too, there are numerous moon-related expressions for a period, ranging from the prosaic Sino-Japanese gekkei ‘moon period’ to the poetic tsuki no sawari ‘touched by the moon’.

This poem is ambiguous in that it could be spoken either by a mother about her daughter, or a girl about herself. Even in metaphor, references to menstruation would become unthinkable for the court poets of later ages.

The plant mentioned in the poem is, more specifically, galingale or umbrella sedge (Cyperus micro-iria). It produces black, edible tubers which is why the lady was out picking it.