Purpletop vervain (Verbena bonariensis): https://en.wikipedia.org/wiki/Verbena_bonariensis; https://www.nies.go.jp/biodiversity/invasive/DB/detail/81250e.html; https://www.gardenia.net/plant/verbena-bonariensis-tall-verbena
Purpletop vervain growing on the roadside, Kofu, Yamanashi, 6/29/2026