The “Oakley Plant,” formally known as Verbena bonariensis, is a popular garden addition. It has gained widespread appeal for its unique airy structure and its ability to attract a variety of pollinators. Gardeners appreciate its delicate appearance, which belies its robust nature.
Understanding the Oakley Plant
Verbena bonariensis is characterized by tall, slender, wiry stems that create a transparent effect, allowing views to plants behind it. These stiff stems can reach heights of 3 to 6 feet and spread 1 to 3 feet wide. It typically forms a basal rosette of deep green, lance-shaped leaves with serrated edges. From mid-summer until the first frost, the plant produces numerous small, rosy-lavender to lilac-purple flowers clustered into rounded heads. Native to tropical South America, specifically Brazil and Argentina, Verbena bonariensis brings a touch of its native warmth to gardens globally.
Growing Conditions and Care
For optimal growth, Verbena bonariensis needs full sun, ideally 6 to 8 hours daily. While it tolerates some partial shade, abundant blooming requires ample sun. The plant prefers well-draining soil and adapts to various soil types, including sandy, loamy, or clay, as long as drainage is good. It generally tolerates average fertility.
Once established, Verbena bonariensis is quite drought-tolerant, but consistent, moderate watering benefits newly planted specimens. Avoid overwatering to prevent root rot. The plant is a tender perennial, hardy in USDA Zones 7 to 11, where it returns year after year. In colder climates, it is typically grown as an annual, often self-seeding for new plants in subsequent seasons.
Pruning maintains its shape and encourages more blooms. Deadheading spent flowers promotes continuous flowering. Cutting back old stems in late winter or early spring, before new growth emerges, encourages bushier growth. Leaving stalks standing over winter can provide food for birds and offer insulation.
Propagation and Garden Use
Verbena bonariensis is known for prolific self-seeding, its primary propagation method. Seeds can be sown directly outdoors in spring or started indoors 8 to 12 weeks before the last frost for earlier blooms. The plant can also be propagated from softwood or semi-ripe stem cuttings taken in spring or late summer.
This plant is highly valued for its airy, see-through quality, adding height and visual interest without obstructing views of other plants. It blends into perennial borders, cottage gardens, and prairie-style plantings, often used as a “filler” plant. Its small purple flowers attract pollinators, including butterflies, bees, and hummingbirds, making it an excellent choice for wildlife-friendly gardens.
Addressing Common Concerns
The most frequent concern is its vigorous self-seeding habit. While this can be advantageous for naturalizing the plant or obtaining new specimens, it can lead to an abundance of volunteer seedlings. To manage this spread, deadhead flowers before they set seed, which also encourages further blooming. Thinning out seedlings in spring helps control population density.
Verbena bonariensis is generally resistant to most pests and diseases. However, it can be susceptible to powdery mildew, especially in humid conditions or areas with poor air circulation. Watering at the base of the plant helps minimize fungal issues. If powdery mildew appears, remove affected parts and improve air circulation.