The Verbena plant genus contains around 250 species of semi-woody, annual and herbaceous perennial plants. The perennial varieties are typically low maintenance and often are used as ornamental plants. Depending on the variety, perennial verbena plants are winter hardy in United States Department of Agriculture plant hardiness zones 3-11.
Tall verbena (Verbena bonariensis) is a South American native that overwinters well in zones 7-11. Sometimes called Brazilian vervain, mature tall verbena plants range from 2 to 4 feet tall and form clumps 18 to 36 inches wide. Tall verbena has deep green, lance-like leaves. Lavender to rosy-violet flower clusters appear from June to frost. This verbena variety prefers moist, well-drained soils in locations that receive full sun to partial shade. Tall verbena sometimes gets powdery mildew, a common fungus, but has no serious diseases or pest problems. Plant tall verbenas in masses in cottage gardens, meadows and mixed borders.
Rose verbena (Verbena canadensis) has clusters of rosy-pink to rosy-purple flowers that bloom from April to October. Also called rose vervian and clump verbena, it grows naturally in Central America and the Southeastern U.S. and does well in zones 5-9. Rose verbena ranges from 6 to 18 inches tall and quickly spreads up to 2 feet wide.This verbena plant thrives in sunny spots and can handle dry conditions. Rose verbena is susceptible to spider mites and mildew. Use rose verbena as a ground cover, an edging plant or a rock garden plant.
American Blue Vervain
American blue vervain (Verbena hastata) grows in the wet meadows, stream banks and river bottomlands of eastern North America. Winter hardy in zones 3-8, this verbena variety grows from 2 to 6 feet tall with spreads of 12 to 30 inches. This plant prefers sunny locations with medium to wet soil conditions and works well in naturalised areas, meadows, native plant gardens or borders. The American blue vervain features slender spikes of purple-blue flowers from July through September. It bears green, toothed leaves and hairy, square stems. This verbena variety has no serious pest or disease issues.
Hoary vervain (Verbena stricta) gets its common name from the fine, white hairs on its greyish-green leaves. This drought-tolerant North American native is suited to zones 4-7 and prefers dry soils and full sun. Its bluish-purple flower panicles bloom from May through September, but flowers most heavily in the summer. Mature plants range from 2 to 4 feet tall and form clumps that spread 18 to 24 inches. Few plant diseases or insects affect this verbena variety. Use hoary vervain in wild plant gardens, meadows or borders.
Garden verbena (Verbena x hybrida) is a tough variety that tolerates heat and drought. It is hardy in zones 9-10; it is grown as an annual in cooler zones. Garden verbena likes locations with full sun and medium moist, well-drained soils. Mature garden verbena plants reach up to 18 inches tall and up to 2 feet wide. The flower colours include purple, blue, yellow, white, red and bicolor. Profuse flower clusters appear from late spring through the fall. The toothed leaves range from a greyish-green to a deep green. Plant garden verbena in rock gardens, window boxes, borders and perennial flower beds.