Artemisia vulgaris L., Mugwort

Account Summary

Growth form and preferred habitats

This tall, stout, strongly scented, aromatic perennial produces a solitary branched stem, or a tuft of them, 60 to 200 cm, but often around 90 cm or less tall, growing erect from a branched rootstock and deeply-penetrating roots. Despite its vigorous underground organs, rather surprisingly, in the somewhat disturbed habitats it often frequents, Mugwort displays little ability to spread laterally by vegetative growth and therefore fails to form large clonal colonies. The stalked, alternate stem leaves are bi-pinnately cut and are divided into sharp-pointed segments. They are green above and woolly-coated white or grey beneath.

Towards autumn, shoots die back and the rootstock produces new, low-growing, wintergreen leaf rosettes that carry the plant through to the spring. Otherwise, the plant relies on seed for overwintering, most germination taking place in the spring following production (Grime et al. 1988, 2007; Sell & Murrell 2006).

A. vulgaris occurs in lowland, rough, tall-herb grassland, mainly in disturbed habitats on moderately fertile, near neutral soils, along roadsides, railways and on waste ground and in other neglected, moist, often poorly drained habitats, generally near habitation. More rarely it grows along grassy river banks and around lakeshores and it is seldom found on acid soils below pH 5.5, which is the pH of the average agricultural soil in most of B & I. Mugwort is absent from woodlands, pastures, wetlands, any unproductive habitat and ground above c 400 m throughout B & I. The almost complete restriction of the species to disturbed lowland habitats is probably due to a combination of current land-use and longer-term climate-related factors (Grime et al. 1988, 2007).

The characteristic deep roots of Mugwort allow it to persist on steep slopes where soil erosion and creep takes place, and the species competes best in situations where other, vigorous competitors cannot match this property, including on rocky ground and in more ruderal situations, such as in cracks or broken areas of paving (Sinker et al. 1985; Grime et al. 1988, 2007).

The established strategy of A. vulgaris is categorised as C/CR, meaning it is intermediate between a straight Competitor and a Competitive Ruderal (Grime et al. 1988, 2007).

Variation

Artemisia vulgaris s.l. is a polymorphic aggregate or species complex that possibly originated in the Pacific region (Hultén & Fries 1986). However, subsp. vulgaris s.s. or var. vulgaris, together with the closely related var. coarctata Forselles, that differs from the former mainly by having its stems and branches suffused brownish-purple, belong to the Eurosiberian temperate phytogeographical element, and they are the forms that occur in B & I. Var. coarctata is probably the most common form in B & I (Sell & Murrell 2006). Both varieties are variable in the degree to which their leaves are dissected and the amount of branching in the inflorescence (Clapham et al. 1987; Sell & Murrell 2006). A variegated form also exists (Grieve 1931).

Flowering reproduction

Flowering takes place from July to September, the individual flowerheads being very small, only 2-3 mm diameter and produced in very large numbers (often more than 1,000/plant), borne in ± dense, terminal leafy raceme or panicle (Butcher 1961). The flowerheads are reddish-yellow and bear a few, whitish involucral bracts. The florets are of two kinds, both of them yellow, tubular and 2.5 mm long. The inner florets are few in number and are bisexual, each having a bell-shaped corolla that terminates in five teeth. The outer florets are all female, tubular and have a smooth, 2-lobed style, a smooth ovary and a rim-like pappus. There is no nectar and the flowerheads, which are fairly inconspicuous and often droop, do not attract insects. Thus it is unsurprising that the flowers are wind-pollinated (Melderis & Bangerter 1955; Hutchinson 1972; Garrard & Streeter 1983).

The achene fruits are oval, hairless (glabrous), grey and finely striate. Although the achenes are not plumed, they are small and light and are, therefore, readily wind-dispersed on account of the height of the flowerheads above ground. They undoubtedly also travel with man and other animals in mud and colonisation of fresh sites is assisted by the fact that a persistent seed bank develops, at least near the site of existing colonies (Thompson et al. 1997). A. vulgaris is known to have considerable colonising ability in disturbed ground with patches of bare soil, the colonisation process greatly facilitated by the species' high level of seed production which averages around 9,000 achenes per flowering stem (Bostock & Benton 1979).

After fruiting and seed release in October, the flowering stems die down (Grime et al. 1988, 2007).

Fermanagh occurrence

The authors of the Revised Typescript Flora working in Fermanagh in the late 1940s and 1950s described A. vulgaris as "frequent" as a ruderal in waste ground in two of their four divisions of the county (I and II), although they list only one station in each of the other two divisions. Mugwort has since declined to such an extent that it is found only very rarely. There are records in the Fermanagh Flora Database from a total of just eleven tetrads scattered in the lowlands, but the plant has only been seen in six of them during the post-1975 period. It is found very locally on waste ground, lakeshores, river banks, a gravel pit and a derelict farmyard.

British and Irish occurrence and status

The New Atlas and Atlas 2020 hectad maps show A. vulgaris thinly scattered but widespread in lowland areas of Ireland, most frequent in the N and E of the island. In Britain, by comparison, it is common and abounds in the southern half, becoming somewhat more coastal N of a line joining Glasgow and Edinburgh.

Until recently, this was considered an indigenous species, but on the basis of a lack of fossil evidence, ruderal habitats and medieval cultivation, the status was revised to that of an archaeophyte in the New Atlas (H.J. Killick, in: Preston et al. 2002) and also Preston et al. (2004). Interestingly, the critical Flora of Great Britain and Ireland by Sell & Murrell (2006, p. 466) continues to describe the species as native.

The Atlas 2020 recognises it as an archaeophyte, often spread by human activities and favoured by its drought tolerance. It has been steadily declining since the 1930s in Britain, and especially so in Ireland and N & W Scotland (Perring & Walters 1962, 1976; Preston et al. 2002; H.J. Killick and P.A. Stroh, in: Stroh et al. 2023).

The decline of A. vulgaris was demonstrated by the BSBI Monitoring Scheme survey, which measured a significant decrease in both Ireland (-29%), and Scotland (-19%) (Rich & Woodruff 1990). On the other hand, in England, it may still be increasing in urban and wayside habitats.

European and world occurrence

A. vulgaris s.s., including the two varieties mentioned above under the Variation section that occur in B & I, has been widely distributed by human settlement and agriculture so that it now stretches across temperate parts of both Europe and Asia, from the Mediterranean northwards to 70^oN in Scandinavia and 74^oN in Siberia (Clapham et al. 1987). It has also been recorded as an introduction in SW Greenland (Böcher et al. 1996) and Hultén & Fries (1986) map it in SW Iceland, although it does not appear in Ostenfeld & Gröntved (1934) or Löve (1983). In the N hemisphere, as an introduction, it penetrates well into temperate China, the southern margins of the Himalaya, India and Sri Lanka. It has also been introduced to N America, mainly in eastern states of the US and Canada (Hultén & Fries 1986, Map 1817).

Toxicity

Mugwort contains the bitter principle absinthin, yet sheep are said to graze it (Grieve 1931). In quantity, however, the plant is toxic and has poisoned grazing stock in other countries, but not in B & I (Cooper & Johnson 1998). According to Grieve (1931) sheep "enjoy the herbage of Mugwort, and also the roots". However, she qualifies this by suggesting what is probably a different form of the plant, "Artemisia of Pontos", reputed to be, "good for fattening the animals and also for feeding to poultry and turkeys" (Grieve 1931).

Where Mugwort is common and abundant, it can cause hay-fever to those allergic to the pollen (Hutchinson 1972).

Uses

In the distant past, before Hops were introduced, the plant was cultivated and used in brewing both to flavour and to clear beer and other drinks and hence its English common name, 'Mugwort' (Grieve 1931; Genders 1971). Another suggested derivation of this name is that it comes from 'moughte', meaning 'a moth or maggot', since in the Ancient Rome of Dioscorides, the plant was used like Wormwood (A. absinthium L.) to keep moths from attacking fabric and to keep biting midges at bay (Grieve 1931; Allen & Hatfield 2004). In Old English, the name is 'mucg-wyrt' or 'mug-wyrt', the Old Saxon 'muggia' referring to the midge insect, plus 'wort' meaning 'plant'. The herb was used to catch and kill biting insects (Grigson 1974).

It was also associated with both medicine and magic, for example, being hung over doorways to keep out the powers of evil. It was even fashioned into cigarettes and smoked by boys and, perhaps, by desperately poor men (Grigson 1955, 1987; Vickery 1995; Allen & Hatfield 2004). The well dried leaves and roots were used medicinally as a stimulant and tonic, having a diuretic (ie inducing urine) and diaphoretic (ie inducing sweating) action, the latter useful for treating colds, heavy coughs and especially consumption (Grieve 1931; Allen & Hatfield 2004). The most important medicinal use was for treating women's aliments, especially for restoring menstrual flow and womb cleansing. It was very likely also used as an abortifacient, although as usual, there is the expected reticence of herb collectors and informants to discuss this particular use of the plant (Allen & Hatfield 2004).

Names

The genus name 'Artemisia' was a name used by Dioscorides for an unknown plant called after Artemis, the Greek goddess of chastity (her Roman equivalent being Diana) (Johnson & Smith 1946; Stearn 1992). The Latin specific epithet 'vulgare' simply means 'common'.

Grigson (1955, 1987) lists 24 alternative folk names from around B & I, ten of them variants of 'Mugwort', including 'Migwort' and 'Moogard'. Vickery (2019) has a higher total, listing no less than 35 alternative common names.

Threats

None.

References

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