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How to Grow Tall Verbena (Verbena bonariensis)
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.
- 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.
Verbena bonariensis syn. Verbena patagonica
Tall verbena, Brazilian vervain
For the best flowering and branching, plants need full sun. However, they will grow and bloom in partial shade.
Mature height depends on the weather and growing conditions, but except the stems to reach anywhere from 2 to 5 ft. tall. We find that plants that have self-sown tend to form a thicker clump than seeds or seedlings we put out.
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.
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 no need to cover them with soil.
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.
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 we have noticed more flowering when we 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 an eye out for the following, just in case.
- Insects: Aphids, scale, slugs, snails, spider mites, whitefly.
- Diseases: Powdery mildew, leaf spot, rust.
We 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, we 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 the water.
Planting it close to yellow flowers or foliage allows 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.
Don’t ask for the moon, when you have this star. We don’t know of any named varieties, but you’ll be happy with the species.Continue to 2 of 4 below.
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Massing Verbena bonariensis
Tall verbena makes a great companion plant, but it also makes an imposing impact when grown in a large swath all on its ownContinue to 3 of 4 below.
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Using Tall Verbena in a Border
Mixing tall Verbena into a border adds height, but retains the airiness. The plants stand tall without any support.Continue to 4 of 4 below.
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Tall Verbena Attracts Pollinators and Hummingbirds
The flowers of Verbena bonariensis may be tiny, but they contain enough pollen and nectar to make them very attractive to hummingbirds as well as bees and other pollinators.