The plant informally known as the “armadillo flower” is a captivating addition to any garden, hinting at its resilient nature and unique presence.
Unveiling the Armadillo Flower
The plant often informally known as the “armadillo flower” is more commonly recognized as Verbena bonariensis, also called Tall Verbena or Purpletop Vervain. This South American native is characterized by its airy, upright growth habit, reaching heights of 3 to 6 feet with a spread of 1 to 3 feet. Its slender, wiry stems host clusters of small, fragrant, lavender-purple flowers, typically about a quarter-inch across, which appear in rounded heads of 2 to 3 inches in diameter. These blooms emerge from mid-summer until the first frost, seemingly floating above other garden plants due to the species’ transparent structure.
Cultivating Your Armadillo Flower
Cultivating Verbena bonariensis requires understanding its environmental needs. It thrives in full sun (at least six hours of direct sunlight daily), though it can tolerate light partial shade.
The plant prefers well-drained soil and is adaptable to various soil types, including sandy, loamy, or average garden soils. A slightly acidic to neutral pH, ideally between 6.0 and 7.5, is beneficial, and good drainage is crucial to prevent root rot. Once established, Verbena bonariensis is notably drought tolerant, requiring only moderate irrigation, though consistent moisture during establishment is helpful. This species is perennial in USDA hardiness zones 7 through 11, where it can survive winters, but it is often grown as an annual in cooler climates.
Ongoing Care and Maintenance
After Verbena bonariensis is established, its care requirements are relatively low. Fertilization is not necessary, as the plant grows acceptably even in poor soil, but it thrives in fertile soils with higher organic matter. The plant’s strong, upright stems do not require staking, though light support might be considered in very windy areas.
Pruning can be employed to manage the plant’s height and encourage bushier growth. Cutting back the main flowering stem in mid-spring, often referred to as the “Chelsea chop,” encourages branching and a more compact form, preventing legginess later in the season. Deadheading spent flowers can prevent prolific self-seeding if unwanted, though leaving seed heads provides winter interest and food for birds. Verbena bonariensis experiences few insect or disease problems, though powdery mildew can occur.
Propagating Armadillo Flower
Propagating Verbena bonariensis can be achieved effectively through both seed and cuttings. The plant is a prolific self-seeder, with tiny seeds often leading to volunteer seedlings appearing in the garden. Seeds can be started indoors 8 to 12 weeks before the last frost, requiring darkness for germination, which can be slow and irregular.
For propagation via cuttings, semi-ripe stem cuttings can be taken in late summer or early fall. Side shoots are best for this purpose, and they root readily in a well-draining compost mix or even in water. Placing cuttings around the edge of a pot can encourage stronger root development.
Landscape Uses and Benefits
Verbena bonariensis offers aesthetic and ecological contributions to a garden. Its airy, see-through habit allows it to be planted anywhere in mixed borders without obscuring other plants, providing vertical interest and a sense of movement. This makes it well-suited for cottage gardens, naturalistic landscapes, and prairie-style plantings.
The plant is a nectar source, attractive to pollinators such as butterflies and bees, supporting local biodiversity. Its long blooming period, from mid-summer until frost, ensures continuous color and interest in the garden. The flowers are excellent for cutting, lasting a long time in floral arrangements.