You see tansy growing wild everywhere, but it's not a herb that I tend to cook with as there are better alternatives to provide bitter lemon tones.
Tansy is of uncertain Eurasian origin and today is a native across the whole of Europe and also naturalised in North America.
Leaves, stems and flowers.
Asteraceae (daisy family).
The leaves have an aroma of lemon and camphor.
The common name "tansy" is from the Middle English tansy, derived from Old French tanesie, Vulgar Latin tanacta and Late Latin tanactum "wormwood", a derivation suggesting confusion with the quite different but equally bitter herb artemisia absinthium. The derivation of tanacetum ultimately originates from Greek thanatos "death", with tansy meaning "immortality".
The species descriptor vulgaris is Latin "common" or "vulgar", from vulgus "the common people", "multitude" or "throng" from the Indo-European base wel- "to crowd or throng" (cf. Sanskrit vargah "division" or "group", Greek eilein "to press or throng" and Welsh gwala "sufficiency" or "enough").
Tansy should be used sparingly in culinary applications because of its bitter flavour, but can be used as a garnish for many savoury dishes. The young leaves, shredded, serve as a flavouring for puddings and omelettes.
Tansy cakes were traditionally baked at Easter as a remembrance of the bitter herbs eaten by ancient Jews at Passover. These cakes were made from the young leaves of the plant, mixed with eggs and were thought to purify the humours of the body after the limited fare of Lent. An old recipe for tansy cake called for beating seven eggs (yolks and whites separately) adding a pint of cream, a similar quantity of spinach-juice, a little tansy-juice, a quarter of a pound of Naples biscuit, sugar to taste, a glass of white wine and nutmeg. The mix should be thickened over the fire in a sauce-pan and then turned out into a tin and baked.
Tansy has been used as a medicinal herb, with a reputation as a remedy for both gout and ague. It is probable that it was this medicinal use, rather than its properties as a spice, that caused tansy to be included in Charlemagne's herbal decree, the Capitulare de Villis.
In Finland the plant is employed as a green dye.