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 special medicinal plant that you can easily grow in your own garden. Learn how to grow verbena yourself here.
Common verbena: origin and properties
Common vervain is a medicinal herb from the Verbena genus and grows around Southern and Central Europe, but you can find it in other temperate or tropical regions. The perennial, herbaceous plant is also known as common verbena or countryman’s treacle.
Common vervain has a square, upright stem with opposite lanceolate or three-lobed leaves and grows between 30 and 80cm tall. It branches out more towards the top and forms spiked inflorescences with white or pink flowers, which appear from June to September. In this time, you can harvest the plant for its medicinal properties or even use it in the kitchen.
If you keep 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 nuts 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 plants may be annual. While verbena only lives for a few years in any case, it can depend on self-seeding for survival.
The best varieties
There is only one known variety of common vervain. There are many other verbena species and varieties, which may not have medicinal uses, but look just as beautiful in the garden as common verbena. Discover one of them here:
Vervain ‘Bampton’ (Verbena officinalis var. grandiflora ‘Bampton’): Variety with 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 soil 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.
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Sowing common vervain:
- Sow directly from May, start seeds indoors from February
- Fill pots with soil or lightly loosen bed
- Plant seeds
- Cover lightly with soil, or not at all
- Gently water
- Ideally keep at 20 °C
- Germination in around 2-3 weeks in right conditions
Before planting the 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 30 cm 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 70 cm deep in the soil. Place a drainage layer, such as pebbles, at the bottom of the pot to avoid waterlogging. Plant the pricked seedlings in a more nutrient-rich substrate, such as our Plantura Organic Flower Compost. Our peat-free soil supplies your verbena with important 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, fertilising etc.
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, but return in spring.
However, there are some verbenas that only grow as annuals and perish in winter.
Soil freezes a lot faster in pots than in the ground, so protect your potted verbenas by wrapping the pot in fleece, placing it on a wooden block and spreading a layer of mulch on the soil.
Propagating common vervain
You can propagate verbena by seed. Harvest seeds straight from the plant after the flowering period or purchase them from garden centres. Common verbena also reproduces on its own if you leave the flowers and plants undisturbed. Sow verbena seeds as described above and transplant them later. If you let verbena self-propagate, you do not have to do anything.
You can also propagate verbena by taking cuttings. This propagation method is very useful if you want to preserve cultivars. In summer or autumn, cut off about 10cm long shoots with sharp scissors and remove the lower leaves. Then 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 use
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 the plant diagonally, just above the ground. Then tie the plants up in bundles and hang them facedown by a string in a warm, dark room until they have dried.
You can store dried verbena, which is usually the 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. Avoid taking the medicinal herb during pregnancy, as it can induce labour.
Has verbena sparked your interest in medicinal herbs? Find more inspiration in our feature article and discover our 10 best medicinal plants for the garden.