A non-native plant that has been around for a long time in Canada, it can spread and form huge thickets for a few years, and then vanish, only to pop up elsewhere. It is a biennial plant. Birds, butterflies, moths, and other insects get caught on these spiky heads. In winter it is birds seeking the seeds encased in these seedpods, and in summer it is moths and butterflies seeking to nectar on the flowers, which can also entrap delicate insects.