Position: Full sun
Soil: Well drained soil
Flowering period: Summer and autumn
Eventual Height: 1.5m
Eventual Spread: 50cm
Hardiness: 7a, 7b, 8a, 8b, 9a, 9b, 10a, 10b
Verbena bonariensis is a deciduous short lived perennial with a clump forming habit. Above the basal clump of dark green, toothed, oblong leaves are upright, branched and wiry stems bearing tufts of tiny, purplish-blue flowers. These are followed by seed heads which produce viable seeds which germinate readily.
Verbena bonariensis, commonly known as Vervain, is native to South America including Colombia, Brazil, Argentina and Chile. It has been naturalised in many of the warmer climates around the world and is considered an invasive weed in parts of North America.
The etymological root of the binomial name Verbena is derived from the French common name of the genus Vervain. Bonariensis is derived from the Latin meaning ‘from Buenos Aires, Argentina’.
Verbena bonariensis may be useful to the landscape architect as part of an informal prairie scheme. This plant is drought tolerant once established, self seeded plants being more drought tolerant than those transplanted.
The Royal Horticultural Society have given Verbena bonariensis their prestigious Award of Garden Merit in 2002.
Verbena bonariensis will tolerate almost any soil conditions; it will be happy in neutral, acid or alkaline pH levels, in loam, clay, chalk or sand based soils facing an exposed southern aspect.
Ecologically, Verbena bonariensis will attract pollinating insects such as butterflies and honey bees and although it is not native to this continent it has been known to attract large numbers of these pollinating insects.
Verbena bonariensis requires little to no maintenance. It may be cut back to the ground level after flowering. To create tougher plants that will not be damaged by winter frosts the stems should be left over the winter months and removed once the spring shoots appear. Unwanted self seeded seedlings can be removed as they appear.