Treated as annuals in our cooler climate, verbenas provide rich color in summer and beyond.
In the hot climates of the sub-tropical and tropical Americas, Verbena flourishes. But in cooler, wetter climates, they tend to be grown as annuals, which has meant they have received little attention.
Verbena bonariensis has become immensely popular in recent years, and at one point, there wasn’t a fashionable garden around without a smattering of the tall, purple flower-headed plants.
Verbena bonariensis comes from South America – as its name suggests, from Bonaria or Buenos Aires – and can grow up to two meters tall by September.
It has rigid, upright stems that are sparsely foliated, giving it a “see-through” look, and by dusk, the flowers look as if they are suspended in the air.
As it never hides other plants, it can be used in a variety of situations.
The shorter trailing verbenas have long been popular bedding plants, perfectly suited to containers and hanging baskets.
A lot of breeding has gone into Verbena x hybrida and Verbena rigida Award of Garden Merit.
Verbenas tend to have intensely colored, compact flower heads, making them well suited to the bedding plant market.
The plants are fairly tough, with stiff, often hairy sterns and leaves that can withstand a fair amount of abuse and aren’t favored by snails or slugs.
Verbena x hybrida will produce stems up to one meter and look good, spreading through the lower branches of roses or other shrubs.
Verbena ‘Sissinghurst’ AGM and Verbena ‘Silver Anne’ AGM are two classic varieties for mixed borders.
Verbena corymbosa ‘Gravetye’ is a strong grower with purple-mauve flowers.
Verbena bonariensis will over-winter in mild southern gardens, provided it is grown in well-drained soil and will readily self-sow. It will flower in its first year and so can be grown as an annual in colder areas.
Verbena must be grown in full sun in any fairly humus-rich and moisture-retentive, but not water-logged soil.
Verbena is easily propagated by seed in autumn or spring and by stem cuttings in late summer.
Young plants should be pinched out to encourage branching. Verbena suffers from a few pests and diseases, though mildew can be a problem.
WHAT THE SPECIALISTS SAY
Kevin Marsh, propagator, Beeches Nursery, Essex: “Verbena bonariensis has to be the best-seller – you can sell plant after plant.
The problem with Verbena is that although it is relatively hardy in the South, most won’t make it through the winter.
A fairly new variety is Verbena ‘Homestead Purple‘, which is hardy in the South and marginally hardy in the Midlands.
It was found in a homestead in Georgia and looked much like a bedding Verbena.
It is mound-forming and 30cm-45cm high. It is effortless to take from cuttings and has perfect purple flowers.
We also sell Verbena hastata, which produces small candelabra-shaped flowers in violet-blue to pinkish purple.
Verbena MacDougall is a bit harder in the North and has a good blue flower. Verbena rigida ‘Polaris’ is a new form with the palest silver-blue flowers and is fast becoming a trendy plant.
Most people don’t know much about Verbena and tend to think of it as an annual, whereas it is a short-lived perennial.
Verbena corymbosa is a relatively unknown species that is particularly nice. Verbenas tend to be impulse buy.
They are relatively trouble-free and suffer from very few pests and disease problems.”
Paul Ingwersen, owner, Birch Farm Nursery, Gravetye, West Sussex: “Verbena is a very showy summer plant that is used mainly in hanging baskets or as bedding.
But they can be grown in the front of a summer border. The main thing with Verbena is that it is not winter hardy, so if people want to keep growing it, they should take cuttings in September.
Tip cuttings are easiest, and with a little hormone powder, they strike very easily. We sell two varieties, which are both very popular.
Verbena peruviana has a very bright red flower and is a low-growing, good-looking plant, while Verbena ‘Sissinghurst’ AGM has a very nice, pink flower and is taller-growing.”
Jim Mountain, partner, the Walled Garden, Suffolk: “Verbena bonariensis is by far the most popular, partly because it gets a lot of press, but mainly because it’s a beneficial plant.
We also sell Verbena hastata, Verbena triphylla, Verbena hastata ‘Alba’ and Verbena rigida AGM. To give you an idea of how popular Verbena bonariensis is, we grow 30 Verbena hastata and 300 plants of Verbena bonariensis. I think that other species are just not showy enough.”
SPECIES AND CULTIVARS
* Verbena bonariensis reaches two meters high and has upright, branching stems with lilac-purple flowers from mid-summer to early autumn.
* Verbena corymbosa has a spreading, rhizomatous habit with erect stems. It has red-purple flowers.
* Verbena hastata is an upright, clump-forming plant with violet-blue to pinkish-purple or white flowers.
* Verbena x hybrida cultivars can be erect and bushy or spread hairy plants, usually grown as annuals. They have white, pink, red, yellow, or purple-blue flowers.
* Verbena x hybrida ‘Imagination’ is a spreading, mound-forming plant with violet-blue flowers. It is good for hanging baskets.
* Verbena x hybrida ‘Raspberry Crush’ has raspberry pink flowers.
* Verbena x hybrida ‘Blue Moon’ has lavender flowers with a white edge.
* Verbena ‘Lawrence Johnston‘ AGM has a spreading habit and cardinal red flowers borne in large corymbs in summer and early autumn.
* Verbena ‘Maonettii‘ has a spreading, prostrate habit with finely cut leaves. It has short spikes of red-violet flowers with white margined lobes.
* Verbena officinalis is best for the herb garden. It has tiny lilac or pale pink flowers.
* Verbena peruviana is a fast-growing, mat-forming, semi-evergreen plant. It has rich scarlet flowers from summer to autumn.
* Verbena peruviana ‘Alba’ produces white flowers.
* Verbena rigida AGM is best grown as an annual. It has fragrant, bright purple, or magenta flowers throughout the summer.
* Verbena rigida ‘Polaris’ forms dense clumps and has silver-blue flowers from early summer to early autumn.
* Verbena ‘Silver Anne’ AGM has an upright, spreading habit with sweetly scented flowers that start bright pink and fade to silver-white with age.
The flowers open in succession through the summer and autumn, giving a multi-tonal effect.
* Verbena ‘Sissinghurst’ AGM is mat-forming with dark green leaves. It has magenta-pink flowers from late spring to autumn.
* Verbena tenuisecta, also known as moss verbena, has thin, linear pinnatifid leaves. It has lilac, mauve, purple-white to blue flowers from summer through to autumn.
Whether a novice or a seasoned veteran, almost every gardener is familiar with the cheerful and nearly indestructible annual verbena.
Nevertheless, there are still many gardeners who are not acquainted with hardy verbenas.
These long-blooming, agreeable perennials are surely some of the hardest-working, least demanding plants ever to inhabit a garden border.
Take, for instance, the steadily increasing number of new introductions that have gained popularity in recent years.
Although most verbenas are native to the warm-winter areas of the Western Hemisphere, many of the new varieties are hardy as far north as Zone 5 or 6.
Their rounded clusters of small flowers bloom continuously, in soft or vibrant colors, from late spring until frost.
Many verbenas are evergreen, survive cold winters or blazing heat equally well, and always look neat.
The handsome foliage, usually emerald green or rich, dark green, is arranged along low, mat-forming, wiry stems.
Extremely vigorous, verbena can expand to cover a 4- to 6-foot area in a single season!
Some varieties take root along their creeping stems, but hardy verbenas don’t self-seed and so never become invasive bullies.
Verbenas are as easy to care for as they are attractive. They love the sun and are extremely heat-tolerant.
My first experience with verbena and its remarkable heat tolerance was living in the oven-like desert of southern Idaho.
With glowing assurances from the mail-order catalog and plenty of doubts, I planted verbena `Homestead Purple’ in a fully exposed location surrounded by cement.
While this position would have meant death by incineration for most plants, my verbena thrived, countering the heat with an outrageous display of vivid purple blooms all summer.
Verbenas are not fussy about soil either. They are happy in almost any situation with reasonable drainage.
Although they are quite drought-tolerant, moderate watering will encourage even more profuse blooming.
Hardy verbenas are exceptionally versatile in the landscape. They look just as lovely trailing from a container as they do clambering down a slope or retaining wall.
Ranging in height from 1 to 12 inches, they make an excellent groundcover around taller plants or shrubs.
They can also be used to wonderful effect as a “weaver,” tying together various plants in a border. Verbena is outstanding planted over spring-blooming bulbs as well.
Its airy mat allows the bulbs to poke through easily while effectively disguising the bulbs’ untidy foliage once it begins to fade.
Hardy verbenas look sensational when planted with silver or blue-gray foliage plants such as artemisia, lamb’s ears (Stachys byzantine), or blue Avena grass (Helictotrichon).
Try purple or pink verbena with lavender, Santolina, catmint (Nepeta), Shasta daisies, or roses.
Red verbena looks great with bright green or variegated ornamental grasses, purple salvia or blue veronica, yarrow, and soft orange- to salmon-colored daylilies.
The possibilities for using hardy verbena in the landscape are practically limitless. Pest- and disease-free, their extravagant blooms and sturdy disposition make them one group of plants that really is too good to be true.
And with the introduction of new varieties every year, it is nearly impossible to resist their irrepressible charm.