Verbena rigida is a perennial herb that reaches 50-60cm in height. It has erect to spreading stems that ascend from creeping rhizomes. Leaves are simple with pinnate venation, dark green in colour, oblong in shape, stalkless and measure 5-10cm in length. They are coarsely serrated, pointed, rigid and covered in rough hairs. Leaf arrangement is opposite/subopposite.Stems end in cylindrical spikes of small fragrant bright purple flowers. Flowers bloom in October – December. Corolla tubes measure up to 9mm long, fruiting spikes measure 20-50mm long. Fruits are dry, separating at maturity into 4 one-seeded segments. Seeds are known as mericarps and measure 2mm long (Moore, 2006; Gilman, 1999; Botanic Gardens Trust, 2009; Sapia News, 2010; Shoot, Undated).\r\n\r\n

Please visit PlantSystematics.org and USDA Plants Profile for Verbena rigida for high quality images of Verbena rigida.

Verbena rigida has an extended blooming period which shows off its vibrant purple colour (Moore, 2006). It is often used for mass planting, ground cover and for flower arrangements (Gilman, 1999). It is heat and drought tolerant making it useful for xeriscaping (Canberra Institute of Technology, 2004). Like many plants, V. rigida can also be used for erosion control on banks and slopes (Moore, 2006). Its fragrant purple flowers are also used for attracting butterflies and bees (Gilman, 1999).

Verbena rigida is capable of naturalizing in habitats that range from disturbed areas to natural forests. In Australia, V. rigida has invaded woodlands, riverbanks and grasslands (Hunter, 1999). In South Africa it is becoming a common roadside weed and has established in climax grasslands (B. van Wyk, pers. comm. in Sapia News, 2010). V. rigida is a popular ornamental species that can flourish in urban environments and is planted along roadsides and highway medians because of easy maintenance and colour (Diamond Jr., 1985).\r\n\r\n

It grows in full sunlight, is very heat tolerant and moderately tolerant to drought, preferring moist but well-drained soils. It can grow in acidic, alkaline and neutral soil pH and on most soil types including sand, loam and clay and chalk (Gilman, 1999; Shoot, Undated).

The spread of Verbena rigida is facilitated by long white rhizomes that help to form dense colonies of the species by spreading out like underground stems in all directions (Russ, 2007). Seeds also play a major role in propagation of V. rigida but their dispersal methods are unclear (Davison, 1999).

Verbena rigida needs full exposure to the sun, and can use reflected sunlight to fulfill this requirement. V. rigida is drought tolerant and requires low amounts of water for survival. It was found that the best landscape performance was with regular irrigation every few weeks (Moore, 2006). In order to see a positive growth rate for V. rigida the soil must be well-drained and the surrounding area must be free from competition and overcrowding to ensure air circulation (Russ, 2007).

Gilman (1999) describes Verbena rigida as an aggressive, spreading plant. V. rigida has invaded woodlands, riverbanks, grasslands (Hunter, 1999) and cotton fields in Australia (Johnson & Hazlewood, 2002). It is a common roadside weed in South Africa.\r\n\r\n

Pammel (1911 in Schmidt, 2010) and Mitchell & Rook (1979 in Avalos & Maibach, 1999) note that V. rigida can cause dermatitis on contact with human skin.