This is a tall, showy plant with large drooping clusters of pale pink flowers. It is probably Polygonum lapathifolium, a native species. We have not seen this at FWG before, but it has appeared near the butterfly meadow this year, and is a new species for our list.

Or it would have been, except someone seems to have destroyed the plant, or else picked it to take home. The plant itself was very tall and very noticeable.