Common wormwood (Artemisia absinthium) was the main ingredient in absinthe, a distilled, highly alcoholic beverage, but it’s technically toxic. It can cause nervous disorders such as headaches, hallucinations, insomnia, convulsions, etc. and is therefore illegal in many countries. Common wormwood may grow like a weed on unmanaged areas, with silvery foliage and small yellow flowers in late summer.
I. Appearance and Characteristics
Artemisia absinthium, otherwise known as common wormwood, is a species of Artemisia native to North Africa and temperate regions of Eurasia, and widely naturalized in Canada and the northern United States. It is grown as an ornamental plant and is used as an ingredient in the spirit absinthe and some other alcoholic beverages.
Wormwood’s relative mugwort was traditionally used as a remedy for a variety of complaints, especially those of a gynecological nature, and so the wormwood genus bears the name of the Greek goddess of childbirth, Artemis. The specific name derives from apsÃnthion, the Greek term for the plant.
“Wormwood” itself is an alteration of Old English wermod, which is of obscure origin. The German cognate Wermut is the source of the term vermouth, used in French and English to describe a kind of wine traditionally flavoured with wormwood.
A. absinthium is a herbaceous perennial plant with fibrous roots. The stems are straight, growing to 0.8–1.2 m (2 ft 7 in – 3 ft 11 in) (and rarely over 1.5 metres (4 ft 11 in)) tall, grooved, branched, and silvery-green.
Leaves are spirally arranged, greenish-grey colored above, white below, covered with silky silvery-white trichomes, and bearing minute oil-producing glands. The basal leaves are up to 250 mm (10 in) long, bi- to tripinnate with long petioles, with the cauline leaves (those on the stem) smaller, 50–100 mm (2–4 in) long, less divided, and with short petioles. The uppermost leaves can be both simple and sessile (without a petiole).
Flowers are pale yellow, tubular, and clustered in spherical bent-down heads (capitula), which are in turn clustered in leafy and branched panicles. Flowering occurs from early summer to early autumn; pollination is anemophilous. The fruit is a small achene. Seed dispersal occurs by gravity.
A. absinthium grows naturally on uncultivated arid ground, on rocky slopes, and at the edge of footpaths and fields. Although once relatively common, it is becoming increasingly rare in Britain, where it has recently been suggested to be an archaeophyte rather than a true native.
II. How to Grow and Care
Sunlight
Common wormwood can tolerate partial shade, but grows best under full sun. A sunny garden border will be a good place for it. If you are growing your common wormwood in containers, place them near a sunny windowsill if indoor, or where bathed in sunlight outdoors.
Temperature
As part of Artemisia genus, common wormwood is hardy due to the wide distribution of this genus – they can be found from temperate to tropical climate zones on both hemispheres, most commonly in semiarid and arid habitats.
Common wormwood is drought-tolerant, just like most perennials with silver-gray leaves (i.e. foliage is covered by silver hairs that can suppress evaporation), and do not have any specific water requirements.
Watering
Seedlings and young plants of common wormwood need regular watering. But once it matures, the plant becomes drought-tolerant, and no additional watering is required then. However, if the plant is cultivated in areas that are rainy or humid, you should pay attention to the drainage of the soil, as it may die back when the soil is soggy.
Soil
Since Artemisia absinthium can survive on a variety of soils, you can use any mix you want. It can grow in loamy, chalky, and sandy soil alike. Additionally, it needs little to no fertilization for growth. However, you can use organic compost to aid its growth. Make sure the soil is well drained since it cannot survive water logging at the roots.
Fertilizing
Common wormwood does not like rich soils, so it does not require any additional fertilizers. Over-fertilization may lead to leggy growth and look badly. Just use a little compost, manure or other organic fertilizers in spring or fall, then it will provide all the necessary nutrients for the plant.
Planting Instructions
You can easily purchase the seeds or seedlings of common wormwood from a nearby gardening store. Choose a sunny location with soil that is poor to moderately fertile and well-drained. Simply sow the seeds or plant the seedlings where optimum for them in spring or fall. If you grow common wormwood in containers, place the pot onto a sunny windowsill.
As it contains compounds that provide a good defense against insects and herbivores, common wormwood can inhibit the growth of edible plants nearby when these chemicals leach into the soil. It is advised to plant common wormwood amongst other species in your garden to protect them. If common wormwood is used as a natural pest repellent, it is necessary to properly isolate it from other plants by planting it into a separate container or at a safe distance (the stem should be at least 1.2 to 1.5 m away from the nearest plants).
Pruning
Pruning method is quite different for different species and cultivars. Generally, you can cut your Artemisia plants back to the base in fall or spring to encourage growth in the following year. While with evergreen or late-flowering species such as tree wormwood (Artemisia arborescens) and sweet wormwood (A. vallesiaca), pruning should be performed in early spring, when there is no danger of frost, but before the new growth starts. Remove wilt flowers as well as dead branches, and leave only new shoots.
If the plant is not pruned, it can get really tall (1.5 to 1.8 m). Trimming some terminal leaves and branches in summer can return the plants that grow wild into a more favorable shape. If the plants get very bushy and thick, the air between the leaves will become more humid – favorable for powdery and downy mildew to develop. Thinning out the plants a little bit to improve the airflow and prevent these diseases. More intensive thinning is necessary if the plants are grown in very humid climates.
Besides, it is very important to wear gloves while pruning common wormwood because its repelling chemicals can also irritate the skin.
Propagation
Common wormwood can be propagated by seeds (some annual Artemisia species are self-sown) or cuttings. Propagation by cuttings includes taking 8 to 10 cm cuttings in late summer and rooting them in a loose, sandy compost or perlite. It is best if the rooting powder is applied before putting the cutting into the medium. Spray water every couple of days to keep it moist.
After a week or two, the cuttings will root. When the roots start protruding from the medium, it is time for a transplant. Rooted cuttings can be put into a separate container or planted directly into the soil in the garden. The distance between the cuttings should be at least 38 cm.
III. Uses and Benefits
- Ornamental uses
Common wormwood is a plant that does well in gardens with poor, dry soil. Its fine silver foliage creates texture in every garden. It is ideal for use in a rock or herb garden and can also be pruned into a border plant. The herb makes a good backdrop for showy plants and also works well will rosemary, onions, and sage.
- Other uses
Artemisia absinthium is claimed to have antifungal, neuroprotective, insecticidal, antimicrobial, anthelmintic, acaricidal, antimalarial, antidepressant, and hepatoprotective properties.
It is an ingredient in the spirit absinthe, and is used for flavouring in some other spirits and wines, including bitters, bäsk, vermouth, and pelinkovac. As medicine, it is used for dyspepsia, as a bitter to counteract poor appetite, for various infectious diseases, Crohn’s disease, and IgA nephropathy.
In the Middle Ages, wormwood was used to spice mead, and in Morocco, where it is called shība (الشيبة), it is used as a complement or substitute for mint in Moroccan tea.
Wormwood was traditionally relatively common as a bittering spice in farmhouse brewing in Denmark, and to some extent Estonia. In 18th-century England, wormwood was sometimes used instead of hops in beer.
Wormwood clippings and cuttings are added to chicken nesting boxes to repel lice, mites, and fleas. Bailen et al. 2013 and Gonzalez-Coloma et al. 2013 find the unique terpenoids of the Gonzalez-Coloma chemotype make this strain especially promising for insect control. As of 2020 a company named EcoflorAgro is investing heavily into increasing the planted area of this strain, hoping to commercialize it to a degree attempted – but never achieved due to unreliable supply – for other botanical insecticides before.
IV. Harvesting and Storage
You can harvest common wormwood as the air-dried herbal aroma. Simply cut common wormwood branches of more than 20 cm long, tie them together at the bottom with a string, and hang the bunch upside down where cool and shaded to dry it out. You may need to tighten the string every several days and will get a fragrant bunch of dry herb after 3-4 weeks.
