Tansy (Tanacetum vulgare) is a perennial, herbaceous flowering plant in the genus Tanacetum in the aster family, native to temperate Europe and Asia. It has been introduced to other parts of the world, including North America, and in some areas has become invasive. It is also known as common tansy, bitter buttons, cow bitter, or golden buttons. The Latin word vulgare means “common”
Description
Tansy is a flowering herbaceous plant with finely divided compound leaves and yellow, button-like flowers. It has a stout, somewhat reddish, erect stem, usually smooth, 50–150 cm (20–59 in) tall, and branching near the top. The leaves are alternate, 10–15 cm (3.9–5.9 in) long and are pinnately lobed, divided almost to the center into about seven pairs of segments, or lobes, which are again divided into smaller lobes having saw-toothed edges, giving the leaf a somewhat fern-like appearance. The roundish, flat-topped, button-like, yellow flower heads are produced in terminal clusters from mid-to-late summer. The scent is similar to that of camphor with hints of rosemary. The leaves and flowers are toxic if consumed in large quantities; the volatile oil contains toxic compounds including thujone, which can cause convulsions and liver and brain damage. Some insects, notably the tansy beetle Chrysolina graminis, have resistance to the toxins and subsist almost exclusively on the plant.
Tansy has also been used as insect repellent. During the American colonial period, meat was frequently rubbed with or packed in tansy leaves to repel insects and delay spoilage. Tansy was frequently worn at that time in shoes to prevent malaria and other fevers; it has been shown, however, that some mosquito species, including Culex pipiens, take nectar from tansy flowers.
Tansy can be used as in companion planting and for biological pest control. It is planted alongside potatoes to repel the Colorado potato beetle, with one study finding tansy reduced the beetle population by 60 to 100 percent.
In England tansy is placed on window sills to repel flies; sprigs are placed in bed linen to drive away pests, and it has been used as an ant repellent.
In the 1940s, distilled tansy oil mixed with fleabane, pennyroyal and diluted alcohol was a well-known mosquito repellent; collectors were paid five cents a pound for tansy in full bloom. Research has found that tansy extracts do indeed repel mosquitoes, but not as effectively as products containing DEET. In 2008, researchers in Sweden investigated the use of tansy to repel ticks, showing a 64–72 percent repellency for each oil constituent.
Toxicity
Many tansy species contain a volatile oil which can cause contact dermatitis in sensitive individuals. If taken internally, toxic metabolites are produced as the oil is broken down in the liver and digestive tract. It is highly toxic to internal parasites, and for centuries tansy tea has been prescribed by herbalists to expel worms. Tansy is an effective insecticide and is highly toxic to arthropods. Because it contains thujone, the U.S. FDA limits the use of tansy to alcoholic beverages, and the final product must be thujone-free. Tanacetum annuum is often confused with common tansy (Tanacetum vulgare) but the former produces an essential oil that is completely different chemically as it contains no thujone and high amounts of chamazulene making the oil dark blue in colour, giving rise to its common name of Blue Tansy Oil.
The active components of the volatile oil include 1,8-cineole, trans-thujone, camphor and myrtenol, with the quantities and proportions of each varying seasonally and from plant to plant. 1,8-Cineole is a toxin believed to defend the plant leaves against attacks by herbivores.
Culinary uses
Tansy was formerly used as a flavouring for puddings and omelettes, but is now almost unknown, except in Cork, where it is used in a sauce to accompany drisheens. The herbalist John Gerard (c. 1545–1612) noted that tansy was well known as “pleasant in taste”, and he recommends tansy sweetmeats as “an especial thing against the gout, if every day for a certain space a reasonable quantitie thereof be eaten fasting.” In Yorkshire, tansy and caraway seeds were traditionally used in biscuits served at funerals.[15]
During the Restoration, a “tansy” was a sweet omelette flavoured with tansy juice. In the BBC documentary “The Supersizers go … Restoration“, Allegra McEvedy described the flavour as “fruity, sharpness to it and then there’s a sort of explosion of cool heat a bit like peppermint.” However, the programme’s presenter Sue Perkins experienced tansy toxicity.
According to liquor historian A. J. Baime, in the 19th century Tennessee whiskey magnate Jack Daniel enjoyed drinking his own whiskey with sugar and crushed tansy leaf.
In the Belgian coastal province of West-Flanders small quantities of crushed dried tansy leaf were traditionally used as culinary herb to spice up pancakes and omelettes. There tansy is colloquially known as “pancake herb”. It can also be used as a substitute for sage.
Ethnomedical use
For many years, tansy has been used as a medicinal herb despite its toxicity. 19th-century Irish folklore suggests bathing in a solution of tansy and salt as a cure for joint pain.[16] A bitter tea made with tansy flowers has been used for centuries as an anthelmintic to treat parasitic worm infestations, and tansy cakes were traditionally eaten during Lent because it was believed that eating fish during Lent caused intestinal worms.[Various Tanacetum species are used ethnomedically to treat migraine, neuralgia and rheumatism and as anthelmintics. Traditionally, tansy was often used for its emmenagogue effects to bring on menstruation or end an unwanted pregnancy, and pregnant women are advised to not use this herb. Research published in 2011 identified 3,5-dicaffeoylquinic acid (3,5-DCQA) and axillarin in tansy as antiviral compounds that are active against herpes simplex virus.
Among Native Americans
The Cherokee use an infusion of the plant for backache, use the plant as a tonic, and wear it around the waist and in shoes to prevent miscarriages. The Cheyenne use an infusion of the pulverised leaves and blossoms for dizziness and weakness.
Other
Why You Should (and Shouldn’t) Grow Tansy
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