What is the personification 'the reed beds sweep and sway to the breeze' describing?

It sounds as though what's being referred to are beds of wheat fields. Their tall stalks (reeds) sweep and sway when the wind (breeze) is blowing from side to side on a hot summer's day just before the harvest. Or it could mean, bamboo reeds swaying a little more rigidly because they're so stiff, but they do still sway nonetheless. They just don't sweep, which is why I chose the former, wheat. The words sound familiar, I was wondering what book. Wordsworth, maybe? "Though nothing can bring back the hour of splendor in the gr, we grieve not, but rather find strength in what remains behind". My favorite next to Robert Frost's "The Road Not Taken", a poem. Look them up. You might like 'em both.