The Okanagan Xeriscape Association

Plant of the Month- September

Verbena bonariensis

Verbena bonariensis, commonly known as purpletop vervain or tall verbena, is a distinctive perennial that has become a favorite among garden designers and wildlife enthusiasts alike. Native to South America, particularly Argentina and Brazil, this striking member of the Verbenaceae family brings an airy, naturalistic quality to garden borders and meadow plantings.

The plant’s most notable feature is its striking architectural form, reaching heights of 3-6 feet with slender, square stems that branch sparingly. These tall, wiry stems are topped with clusters of tiny, tubular purple flowers arranged in flat-topped corymbs. The blooms appear from midsummer through fall, creating a misty purple haze effect that seems to float above other plants in the garden.

Despite its height, Verbena bonariensis has a delicate, see-through quality that prevents it from overwhelming neighboring plants. The narrow, toothed leaves are relatively sparse, concentrated mainly at the base and lower portions of the stems. This open structure allows the plant to weave seamlessly through mixed borders without blocking views or creating visual barriers.

Butterflies, bees, and other pollinators find the nectar-rich flowers irresistible, making this verbena an excellent choice for wildlife gardens. The plant is also valued by birds, who feed on the seeds in autumn and winter.

Cultivation is remarkably straightforward, as Verbena bonariensis thrives in full sun and well-draining soil. It demonstrates excellent drought tolerance once established and actually performs better in poor to moderately fertile soils. The plant readily self-seeds, often appearing in unexpected garden locations, though it’s not considered invasive.

While technically a tender perennial, it’s often treated as an annual in colder climates and is certainly considered as such here in the Okanagan; however, in USDA zones 7-11, it reliably overwinters. This versatile plant excels in cottage gardens, prairie-style plantings, and contemporary naturalistic designs, where its ethereal presence adds height, movement, and seasonal interest.

UPCOMING EVENTS

Did you know?

1. There is LESS water available per person in the Okanagan than anywhere else in Canada
2. The Okanagan has one of the highest rates of water use per person in Canada
3. The 2nd largest use of water in the Okanagan is for watering our household lawns & gardens

Here’s a reminder to check out the Make Water Work website to make your pledge to reduce water waste.

You will also find valuable information such as these useful PDF publications–
Make Water Works Tip Sheet and Make Water Works Plant Collection

Xeriscape is a very effective way to Make Water Work.