Overview

Don’t let the dainty flower heads fool you, tall verbena is one hardy, vigorous plant. Although it can grow to 6 ft. in height, it remains airy enough to allow you to see what’s behind it. This is one of the best filler plants for any garden, as it seeds itself between other plants without squeezing them out. Verbena bonariensis is native to South American and flourishes in sunny, warm gardens.

Description

• Leaves: Plants form a cluster of basal leaves. Stems are long, slender, square, branching stems up to 5 ft. tall . Leaves are lance-shaped and sparse on the stems.

• Flowers: The small, violet-purple flowers form in clusters. Plants start blooming in mid-summer and continue until frost.

Botanical Name:

Verbena bonariensis syn. Verbena patagonica

Common Names:

Tall verbena, Brazilian vervain

Hardiness Zones

Tall verbena is perennial in USDA Hardiness Zones 7 and higher. In other areas, it is a fast growing annual that will re-seed itself.

Light Exposure

For the best flowering and branching, plants need full sun. However they will grow and bloom in partial shade.
 

Mature Size

Mature height depends on the weather and growing conditions, but except the stems to reach anywhere from 2 - 5 ft. tall. I find that plants that have self-sown tend to form a thicker clump than seeds or seedlings I put out.

Bloom Period:

Perennial plants will start blooming as soon as the plants have had a few weeks to resume growing. Plants grown as annuals should start blooming by mid-summer. The seed is slow to germinate in the spring, so keep an eye out for the seedlings and don’t weed them out.

Growing Tips

Verbena bonariensis blooms best with regular moisture, but well-draining soil.

To achieve that, make sure your soil has plenty of organic matter worked in. It is not particular about soil pH, but prefers something in the neutral range (6.0 - 6.8).

Starting from Seed: You won’t often find seedlings of Tall Verbena. You can start your own seed indoors, but you don’t gain much time by doing this. It’s easiest to simply scatter seed, in fall or early spring. There’s not need to cover them with soil.

Perennial tall verbena can be divided, to make more plants. The ideal time for this is early spring. You could also propagate from cuttings.

Caring for Verbena bonariensis

Water: Once established, tall verbena is very drought resistant, but it does best with regular water. An inch a week should do it.

Fertilizer If you added plenty of compost to the soil, annual plants should not need any supplemental fertilizer. Perennial plants will appreciate a does of food in early spring.

Maintenance: Tall verbena does not require much attention. The plants don’t require staking. There’s no need to pinch the plants. They will branch on their own. You also don’t need to deadhead, although I have noticed more flowering when I shear the plants back once or twice a season.

Pests and Problems:

Annual plants are rarely bothered by pests. Perennial plants can be more susceptible, but even they grow rather problem free. Keep and eye out for the following, just in case.

• Insects: Aphids, scale, slugs, snails, spider mites, whitefly.
• Diseases: Powdery mildew, leaf spot, rust.

Design Tips:

I have never seen tall verbena look out of place. It really shines when used in a mixed border or cottage garden and allowed to grow between and through other plants. However I have seen it used to great effect when planted alone in large swaths, where it makes a haze of purple. It makes a great, long blooming plant for the edge of water.

Planting it near yellow flowers or foliage allow the color of the flowers to stand out. It mixes equally well with other airy, cottage flowers, like cosmos, as it does with bolder forms, like Hosta, Sedum, and Joe-Pye Weed.

Suggested Varieties:

Don’t ask for the moon, when you have this star. I don’t know of any named varieties, but you’ll be happy with the species.