Common Name: Wormwood

General Information

Artemisia absinthium is a herbaceous, perennial plant producing 1 - 3 stems 60 - 150cm tall that become somewhat woody at the base[].
The plant is harvested from the wild for local use as a medicine. It is a popular ornamental in the garden and is also sometimes grown in the herb garden and as an insect repellent[, ].

Known Hazards

The essential oil in this plant contains thujone. Thujone is a GABA receptor antagonist which allows neurons to fire more easily. In larger doses this can cause muscle spasms and convulsions, and can also be toxic to brain, kidney, and liver cells.
There has been a lot of negative press regarding thujone, particularly in the mid 19th century when thujone was reported to be more dangerous than alcohol - since shown to be exaggerated; and reports in the 1970’s that it might have a similar effect on the brain to THC (found in cannabis) – since found to be incorrect.
Thujone is probably best known for its use in the alcoholic drink ‘Absinthe’. It is also found in the essential oils of many other plants that are used in herbal medicines and foods, including Arborvitae (Thuja species), some Junipers (Juniperus species), Wormwoods (especially Artemisia absinthium) and Sage (Salvia officinalis). There are some legal restrictions in various countries on the quantity of thujone that can be added to foods and drinks and these vary between countries.
Side effects from consuming thujone can include sleeplessness and anxiety but, unless the pure essential oil is used, the quantity of thujone found in plants is well within safety levels. Pregnant women, however, may be advised to restrict their use of thujone-containing plants.
The plant is poisonous if used in large quantities[, ]. Even small quantities have been known to cause nervous disorders, convulsions, insomnia etc[]. Just the scent of the plant has been known to cause headaches and nervousness in some people[].

Botanical References

, ,

Range

Temperate regions of Europe and Asia, including Britain, north to Lapland and Siberia.

Habitat

Waste land, rocks and screes[, , ]. Hillsides, steppes, scrub, forest margins, often in locally moist situations; at elevations from 1,100 - 1,500 metres in China[]..

Properties

Edibility Rating
Medicinal Rating
Habit	Perennial
Height	1.00 m
Pollinators	Wind
Cultivation Status	Ornamental, Wild

Cultivation Details

Succeeds in any soil but it is best in a poor dry one with a warm aspect[]. Established plants are very drought tolerant[, ]. Plants are longer lived, more hardy and more aromatic when they are grown in a poor dry soil[]. Easily grown in a well-drained circumneutral or slightly alkaline loamy soil, preferring a sunny position[, ]. Prefers a shady situation according to another report[]. Tolerates a pH in the range 4.8 to 8.2.
Wormwood is occasionally grown in the herb garden and as an ornamental, there are some named forms[].
Wormwood has been shown to have allelopathic properties[]. Volatile emanations from its leaves completely prevented germination in wheat, and inhibited seedling growth in wheat, hoary cress and common flax, whereas seedling growth on white mustard was markedly stimulated[]. Extracts made from the leaves prevent germination on all the above species, and extracts of roots prevented germination of wheat and reduced root and shoot elongation in hoary cress, common flax and white mustard by 53 - 85%[].
The scent of the plant attracts dogs[].
Members of this genus are rarely if ever troubled by browsing deer[].

Edible Uses

Leaves are occasionally used as a flavouring[, , ]. Caution is advised, prolonged use is known to have a detrimental effect - see the notes above on toxicity[].
This herb was at one time the principal flavouring in the liqueur 'Absinthe' but its use has now been banned in most countries since prolonged consumption can lead to chronic poisoning, epileptiform convulsions and degeneration of the central nervous system[].

Medicinal

Wormwood is a very bitter plant with a long history of use as a medicinal herb. It is valued especially for its tonic effect on the liver, gallbladder and digestive system, and for its vermicidal activity[, , ]. It is an extremely useful medicine for those with weak and under-active digestion. It increases stomach acid and bile production, improving digestion and the absorption of nutrients[]. It also eases wind and bloating and, if taken regularly, helps the body return to full vitality after a prolonged illness[].
Use with caution[], the plant should be taken internally in small doses for short-term treatment only, preferably under the supervision of a qualified practitioner[]. It should not be prescribed for children or pregnant women[]. See also the notes above on toxicity.

The leaves and flowering shoots are anthelmintic, anti-inflammatory, antiseptic, antispasmodic, antitumor, carminative, cholagogue, emmenagogue, febrifuge, hypnotic, stimulant, stomachic, tonic and vermifuge[, , , , , , ]. The extremely bitter leaves are chewed to stimulate the appetite[]. The bitter taste on the tongue sets off a reflex action, stimulating stomach and other digestive secretions[]. The leaves have been used with some success in the treatment of anorexia nervosa[].
The plant is applied externally to bruises and bites[]. A warm compress has been used to ease sprains and strained muscles[].
The plant is harvested as it is coming into flower and then dried for later use[].

A homeopathic remedy is made from the leaves[]. It is used to stimulate bile and gastric juice production and to treat disorders of the liver and gall bladder[].

Agroforestry Uses:

The growing plant is said to inhibit the growth of fennel, sage, caraway, anise and most young plants, especially in wet years[, , ].
Wormwood is a good companion for carrots, however, helping to protect them from root fly[].

Other Uses

The fresh or dried shoots are said to repel insects and mice[, , , ], they have been laid amongst clothing to repel moths and have also been used as a strewing herb[, , ]. An infusion of the plant is said to discourage slugs and insects[, , ].
The plant contains substances called sesquiterpene lactones, these are strongly insecticidal[].

Propagation

Seed - surface sow from late winter to early summer in a greenhouse. The seed usually germinates within 2 - 26 weeks at 15°c[]. When they are large enough to handle, prick the seedlings out into individual pots. They can be planted out in the summer, or kept in pots in a cold frame for the winter and then planted out in the spring.
Cuttings of half-ripe wood, mid summer in a frame.
Division in spring or autumn.