Verbena bonariensis

Verbena Bonariensis is a perennial plant that flowers in late summer to mid-autumn. It has tall, architectural stems with sparse leaves, crowned by flattish heads of lavender-purple flowers. This is a wonderful plant for bringing height to the border and its airy structure allows you to see through to the plants behind.
Grow Verbena bonariensis in moist but well-drained soil in full sun. Given the right conditions, plants will self-seed freely, but in colder regions they may need protection from frost. Leave dead stalks to provide winter interest and mulch annually with well-rotted manure or compost. 1.5m high by 45cm spread.