Common verbena: location, harvest and hardiness

Common vervain is a well-known medicinal herb that not only relieves digestion but also helps with anxiety and sleep disorders.

Common vervain (Verbena officinalis) is a medicinal plant that you can easily grow in your own garden. Read on to learn how to grow common verbena at home.

Common verbena: origin and properties

Common vervain, also known as common verbena and countryman’s treacle, is a perennial medicinal herb from the Verbena genus that is native to the UK and Europe and is naturalised in many parts of the world including North America.

Common vervain has a square upright stem with opposite lanceolate or three-lobed leaves and grows 30 to 80cm tall. It branches out towards the top and forms spiked inflorescences with white or pink flowers from June to September. During flowering, you can harvest the plant for its medicinal properties or even use it in the kitchen.

If you grow common vervain in your garden, bees and bumblebees as well as butterflies will happily feast on the herb’s nectar, thereby pollinating it and helping it reproduce. After flowering, the plant forms fruit, which turn into four small seeds after ripening. The light brown ridged seeds then spread by the wind as well as by human or animal carriers.

Generally, common vervain is perennial, but some varieties may be annual. Common verbena only lives for a few years anyways, so it depends on self-seeding for survival.

The best varieties

There is only one known variety of common vervain but there are many other types of verbena that may not have medicinal uses but look just as beautiful in the garden as common verbena.

Vervain ‘Bampton’ (Verbena officinalis var. grandiflora ‘Bampton’): has purple foliage and small pink flowers. Needs frost protection, as it is not hardy and only tolerates cold down to about -10 °C.

Planting common vervain: location and method

When growing verbena in the garden, prepare the soil well before planting. Once it is in a suitable location, common verbena does not require much plant care. While common verbena still thrives in partial shade, a bright and sunny location is ideal because it encourages large and vigorous growth. Provide common vervain with well-drained, rather dry soil that is low in nutrients. Add sand to heavy soil to make it more permeable.

Sow seeds directly from the end of April or start them on a windowsill from February. Use low-nutrient soil for sowing, such as our Plantura Organic Herb & Seedling Compost, so that the seeds can develop properly. Our compost is specifically made for seed propagation and does not contain any peat. Only lightly, if at all, cover the seeds with soil, as they need light to germinate.

Sowing common vervain:

• Sow directly from May; start seeds indoors from February
• Fill pots with soil or lightly loosen bed
• Sow seeds
• Cover lightly with soil or not at all
• Water carefully
• Ideal temperature: 20 °C
• Germinates after 2-3 weeks in right conditions

Before planting the common verbena seedlings, fertilise the soil with some slow-release fertiliser, such as our Plantura Flower Food. The nutrients give the seedlings what they need to grow strong, and our fertiliser is harmless to pets and garden wildlife. The fertiliser lasts all season, as verbena does not need many nutrients. From May, prick out and transplant the seedlings, spacing them 30cm apart or around eight plants per square metre.

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You can also grow common vervain in pots. Choose a deep container, as verbena’s roots can reach up to 70cm deep in the soil. Place a drainage layer, such as pebbles, at the bottom of the pot to avoid waterlogging. Plant the pricked out seedlings in a more nutrient-rich compost, such as our Plantura Organic Flower Compost. Our peat-free soil supplies your common verbena with the essential nutrients so that you do not need to fertilise it in the first few months. The loose permeable structure lasts for a long time, and you can improve it even more for the plant if you add some sand.

Common vervain: plant care

Although verbena is a low-maintenance garden plant, you can make sure the plant consistently grows well and stays healthy by taking proper care of it. In general, verbena needs more care when planted in a pot.

Watering and fertilising

Common vervain can tolerate droughts but no waterlogging whatsoever. Only water the flower bed when it is hot and dry for an extended period of time so that the soil does not completely dry out. As soil in pots dries out much quicker than out in the open, water potted verbenas regularly. Use your finger to check whether the upper third part of the substrate is still moist or whether you need to water it again.

The same applies to fertilising common vervain plants. If you have already improved the soil with some slow-release fertiliser before planting, you will not have to fertilise it again until the following spring. Potted verbenas have less soil available to them and will benefit a lot if you mix in a slow-release fertiliser at the start of the growing process. As the fertiliser will last the whole season, do not fertilise the plant again so that it keeps its own beneficial nutrients.

Pruning common vervain

There are different reasons for pruning verbena. Deadhead the flower spikes to extend the flowering period somewhat. Cut back verbena before winter, as its above-ground parts die off anyway and pruning helps the plant put its energy into its roots instead. Prune frost-sensitive varieties in spring to keep them protected through winter. Apart from that, only cut verbena when using it for medicinal purposes. Harvest flowers and leaves or the whole plants during the flowering period and dry them.

Is common vervain hardy?

Generally, common vervain plants are hardy in most UK regions and can even tolerate temperatures down to -30 °C. The plant’s above-ground parts die off in winter, returning in spring. However, there are some verbenas that only grow as annuals and die come winter.

Soil freezes a lot faster in pots than in the ground. So, to protect your potted common verbenas, wrap the pot in fleece, place it on a wooden block and spread a layer of mulch on the soil.

Propagating common vervain

You can propagate common verbena by seed. Harvest seeds straight from the plant after the flowering period or purchase them from garden centres. Common vervain also reproduces on its own if you leave the flowers and plants undisturbed. Sow common verbena seeds as described above and transplant them later. If you let common vervain self-propagate, you do not have to do anything.

You can also propagate common verbena by taking cuttings. This propagation method is very useful if you want to preserve cultivars. In summer or autumn, cut off 10cm long shoots with sharp secateurs and remove the lower leaves. Put the shoots in moist potting soil and leave them somewhere warm and bright indoors. Repot cuttings that have formed roots over winter and keep them indoors until the end of April. You can transplant them outside from May.

Harvest, effect and uses

If you want to use common vervain for medicinal purposes, harvest when the plant is in flower. The best time for this is in the morning, when the flowers are still closed or just barely open. Cut off the entire plant diagonally, just above the ground. Then tie the plants up in bundles and hang them facedown in a warm dark room until they are dried.

You can store dried common verbena leaves in a jar to make tea from. Common vervain tea helps against stress, digestion problems and even anxiety or sleep disorders. It also relieves cramps and fevers. Do not take the medicinal herb during pregnancy, as it can induce labour.