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| Verbena bonariensis L. | ||||||||||||||
Verbena bonariensis (purpletop vervain, purpletop, Brazilian verbena, tall verbena, clustertop vervain, South American vervain, pretty verbena) is a member of the Verbena Family (Verbenaceae) cultivated as a garden annual or perennial.
Description
V. bonariensis is a tall and slender-stemmed perennial. It can grow to 4’ tall and can spread to 3’ wide. At maturity, it will develop a woody base. Fragrant lavender to purple flowers are in tight clusters located on terminal and axillary stems, blooming from mid-summer until fall frost. The stem is square with very long internodes. Leaves are ovate to ovate-lanceolate with a toothed margin and grow up to 4” long.
Taxonomy
There are two named subspecies. V. b. bonariensis and V. b. conglomerata. (need a reference to describe differences) Synonyms: V. patagonica
Distribution
Found throughout most of South America from Columbia and Brazil to Argentina and Chile.
Uses
Ethnobotanical uses
V. bonariensis is reportedly used as a veterinary abortifacient in Australia, although details are lacking.
Cultivation
Verbena bonariensis is a tall, slender-stemmed cultivated plant. It is a tender perennial hardy in USDA Zones 7-11. It can be grown as an annual in areas where it is not winter hardy and will bloom in the first year when grown from seed. Its long internodes give it a sparse appearance but allow it to intermingle and coexist with other plants. Flowers bloom all summer and range in color from lavender to rose-purple.
V. bonariensis is commonly grown from seed which germinate readily without pre-treatment, but also can be propagated from herbaceous stem cuttings.
V. bonariensis grows best in a well drained soil. It prefers full sun to partial shade and needs regular moisture. The flowers are very attractive to butterflies. The small flowers provide nectar for native bees and many beneficial garden insects. It is reportedly free of insect pests but may be susceptible to powdery mildew.
Weed status
V. bonariensis self-seeds readily. This ability has raised concerns that it may become invasive in favorable habitats. It has naturalized in a number of southern states.
- V. bonariensis is on the watchlist for Washington State (http://www.nwcb.wa.gov/weed_info/Written_findings/Verbena_bonariensis.html)
- Naturalized in tropical and southern Africa, temperate Asia, Australia, New Zealand, United States (including Hawaii), West Indies, Macaronesia, & Mascarenes
- Considered a weed in Fiji, New Guinea and many other South Pacific islands according to Pacific Island Ecosystems at Risk.
References
Bailey, L.H. 1951. Manual of Cultivated Plants. [Macmillan Publishers Macmillan Publishing Company]. p. 840.
USDA Plants Profile: Verbena bonariensis
Germplasm Resources Information Network: Verbena bonariensis
Integrated Taxonomic Information System Verbena bonariensis