while the flowers float away.
Once again, "we" is mentioned, and the reader must choose between being the passive observer or the active participant. Note "the flowers float away." This refers to the flower petals floating aimlessly away from the first stanza. It seems interesting that the flowers and the river are once again mentioned. Because the river and the boy are somehow and somewhat connected, then one can deduce that the boy and the flowers are as well.
Significance: These lines provide the reader with a last ditch description of the physical undergoings of the group of people. As it will be shown, the subsequent lines have their own sort of interpretations of the circumstances.