Aromatic Herbs: Tansy

Tansy {Tanacetum vulgare}

Tansy is an upright herb with a crown of bright yellow clustering flowers. It is a member of the Asteraceae family and is also known as common tansy, bitter buttons, cow bitter, mugwort, and golden buttons. It grows to a height of three feet and produces pinnate, lance-shaped leaves that are uniformly toothed. Its button-shaped flowers sit atop erect, reddish stems.

Native to Europe and Asia – and of possible Asian origin – the plant was likely first cultivated as a medicinal herb by the Greeks. In the eighth century, it grew in the herb gardens of Charlemagne and at the Abby of Saint Gall in present-day Switzerland, now a UNESCO World Heritage Site. At that time, it was used to treat worms, digestive issues, rheumatism, fevers, sores, and to cause the eruption of measles. In the Middle Ages, high doses were administered to induce abortions, while lower doses were thought to encourage conception. During the Catholic Lenten season, tansy served with meals to replicate the bitter herbs eaten by the Israelites. By the 16th-century, the British considered tansy “necessary for a garden.”

Aromatic Qualities

The oddly agreeable scent of tansy is similar to that of camphor, with some hints of rosemary. It is used as an ingredient in some expensive perfumes. It was also long used in embalming; it would be packed into coffins and wrapped in winding sheets to ward off worms.

Its medicinal benefits may be in question, but tansy still offers a major boon to humans – it is a powerful insect repellent. At one time, farmers planted tansy in valuable orchards to keep away aphids and other destructive insects. In England, tansy was hung in windows to keep out flies and placed in bedding to repel moths and fleas.

Culinary Uses

Even though Europeans used tansy as a seasoning from the Middle Ages on, we now know that the leaves and flowers can be dangerous if consumed in large quantities. The herb’s volatile oil contains toxic compounds, including thujone, and ingesting too much tansy can cause convulsions and liver and brain damage. The flower extract is still used as a flavor corrective by the liquor industry.

Healing Properties

Tansy had a centuries-long run as a medicinal herb and was valued by herbal healers of many nations. During the Middle Ages, a bitter tea made with the flowers was used to treat parasitic worm infestations. In the 15th century, Christians regularly ate tansy cakes during the Lenten season because it was believed that the heavy diet of fish during that season could cause intestinal worms. Tansy was also used for treating migraine, neuralgia, and rheumatism.

Recent research has shown, however, that due to the presence of thujone, this herb can be dangerous to ingest in any but the smallest quantities.

Tansy has also been used to repel human pests like flies, midges, and mosquitoes, and a 2008 Swedish study showed that tansy oil had a 64 percent effectiveness rate in repelling ticks.

As a companion planting, it has many uses – tansy can repel the Colorado potato beetle, sometimes reducing the population by as much as 60 percent, and it keeps destructive pests away from cucumbers and squash, as well as roses and some berries.

History and Lore

  • Nineteenth-century Irish folklore insisted that bathing in a solution of tansy and salts would cure joint pain.
  • Some beekeepers use dried tansy as fuel in their smokers.
  • During the English Restoration, a “tansy” was a sweet omelet flavored with tansy juice.