This is an image I took at Hampton Court, not part of the Show but an interesting plant nonetheless. Verbena bonariensis was one of the first identifications our class had at college on the horticulture course and very nice it is too. It grows abundantly but is subtle and distinguished. According to BBC, "this is a short-lived perennial, and because it is borderline hardy, plants may be damaged by winter frosts. This may be avoided by leaving the dead stalks until spring, when new growth is evident, before cutting them back. A protective mulch should be added around them in the autumn with leaf mould or compost. They do, however, self-seed liberally and resulting seedlings are stronger and more drought-tolerant than those that are transplanted. This is a superb butterfly plant, rivalling even buddleja. The Royal Horticultural Society have given it the Award of Garden Merit." It is indeed a very nice plant.
Common Name: Verbena
Skill Level: Beginner
Exposure: Full sun
Hardiness: Half Hardy
Soil type: Well-drained/light, Moist
Time to plant seeds: March to April
August to October