How to grow Verbena

BOTANICAL NAME

Verbena

COMMON NAME

Verbena, Vervain.

NATIVE TO

The native range of verbena is global, otherwise known as ‘cosmopolitan’.

DESCRIPTION

Most commonly the light purple, flattened flowerheads of the perennial verbena bonariensis are seen in gardens. However, there is a plethora of other varieties available which include more colour options to enjoy through summer and into the autumn months.

The domed clusters of small flowers appear on tall, slender stems, creating a delicate and romantic look in the garden.

There are two key types of vervain to consider for your garden. There are summer bedding varieties and perennial varieties.

Summer bedding varieties are less hardy, and tend to be more compact, but have a much more vast colour range. These are perfect for if you are looking for features for the front of your borders, for handling baskets, and containers.

If you want a hardier perennial which will come back every year, Verbena bonariensis offers great height, whilst Verbena rigida is more compact and denser.

This is dependent on the variety of Verbena you have. Verbena bonariensis is one of the taller perennial varieties, often reaching up to 2 metres tall. Other verbenas are much more compact, only reaching about 30cm in height, so make sure you check the variety you are growing for the best idea.

Verbena is straightforward to plant provided you choose the right position in your garden for them. Sunny positions with well-drained soil are great basics to aim for.

If planting bedding verbenas, plant them after the last frost of the winter has passed. You can rely on this being the case from around mid-May. Acclimatise them to outside conditions for a few days before planting.

Hardier perennials can be planted in spring once the soil has started to warm, but if purchased in summer or autumn, plant them as soon as you bring them home. Especially if planting whilst in flower in summer, make sure you water the plants well.

If you are growing verbena in containers, water regularly as the compost will dry out more quickly than in garden beds. Water close to the base of the plant, as watering the leaves or flowers can increase the chance of fungal disease.

If you’ve chosen to plant your verbena in a garden border, ensure you mulch it after planting. This reduces the chance of weed growth and helps the soil to retain moisture.

Bedding verbenas, being less hardy, should be discarded once autumn comes around. Alternatively, perennial border verbenas can live for several years. Mulch them in autumn, or if in containers, move them to a protected, sheltered area for the winter.

Yes, many perennial verbena varieties can spread by self-seeding. Varieties such as Verbena bonariensis and Verbena rigida are renowned for being able to self-seed.

Any old flower stems of perennial verbenas need to be cut down before spring, as this is when new growth emerges. By cutting them down, more stems should sprout, meaning more blooms that year.

Other than this, verbenas don’t require much maintenance to keep looking good.

Verbena does not need to be deadheaded, but doing so may encourage more flowers. However, if you can resist the temptation to deadhead, the seedheads are beneficial to birds.

No, vervain does not need to be pruned. Cut old flowering stems down before the spring to encourage more growth.

Generally, verbenas are pest and disease-free. However, a couple of things to be aware of may crop up.

Thrips may cause mottled foliage and flowers but will generally not harm the plant too much. Tolerate the damage if you can and encourage natural enemies like Orius laevigatus into the garden.

You may also see Glasshouse leafhopper damage, causing pale mottling which doesn’t fade. The leafhoppers are about 3mm long, pale yellow, with grey markings. Much like thrips, tolerate the damage if you can, as it won’t harm the plant. Natural predators like birds, ladybirds and ground beetles should be encouraged into the garden.

Finally, powdery mildew may occur. This is a fungal disease leaving patches of white powdery on the surfaces of leaves or flowers. Dispose of any infected leaves which have fallen and prune out infected shoots. Make sure plants are in full sun if possible, and don’t plant too densely to avoid spread.

One of the most tried and true verbena varieties is Verbena bonariensis. It has earned the RHS Award of Garden Merit and is an RHS Plant for Pollinators. It grows up to 2 metres tall, with delicate clusters of lilac flowers appearing on the end of each stem. Also, it’s fantastic for a variety of different garden styles.

Another great perennial variety, Verbena rigida (slender vervain) has rounder clusters of bright purple flowers than V. bonariensis. These are often grown as annuals and more compact up to 60cm, it’s a lovely bright variety to try.

For even more impactful blooms, Verbena rigida f. lilacina ‘Polaris’ is quite striking. The pale-lilac flower clusters are slightly larger than other varieties, giving an impactful pop in the garden.

If you would prefer an alternative shade of verbena, Verbena hastata ‘White Spires’ grows up to 1.2 metres with small, white flowers on short spikes.

These delightful plants are very versatile and suit quite a range of garden styles. However, you can most often expect to see them in a cottage, coastal, courtyard, prairie, wildlife, or container-style garden.