Verbena bonariensis, or purpletop vervain, is a tall, see-through perennial reaching around 2m. Clusters of nectar-rich lilac-purple flowers top its slim, wiry stems from summer into autumn, and butterflies and bees love them.
It prefers full sun and well-drained soil, and often self-seeds around the garden. The height and airy stems work from the back to near the front of a border.
