Tanacetum Vulgare or Tansy is a herbaceous perennial with yellow flowers. It is native to Europe and Asia and part of the Aster family, or Asteraceae. It is also known as Common Tansy, Cow Bitter, Golden Buttons, or Bitter Buttons. It has compound foliage and flowers are like buttons. It has an erect stem that is slightly reddish. It can grow to about 1.5m or 5ft. It flowers in the summer. It is an aromatic plant with a scent similar to rosemary.
It was used to deter flies even on meat it was rubbed and leaves set next to it to deter flies. However, the leaves and flowers if consumed in larger quantity are toxic as they contain thujone causing liver and brain damage. One insect being immune to it Tansy Beetle or Chrysolina graminis actually feeds on it.
However, throughout the years Tanacetum Vulgare has been used for medicinal purposes first by Greeks and later in France and Switzerland. It was used for digestive problems and treating intestinal worms, rheumatism, and fever. In the middle ages, Tansy was even used to induce abortions. They even used it for bathing in Ireland to help with joint pain.
Because of its insect repellent and worm warding properties, it was used in funerals in the 18th and 19th centuries. Even in 1940s tansy oil has been used for insect repellants. Tansy or Tanacetum Vulgare was also used in cooking in puddings and omelets, but it is no longer being used. Native Americans also used the oil for backaches or for dizziness.
Tanacetum Vulgare is also traditionally planted next to potatoes to keep the healthy. It is hardy and not frost tender. The plants do attract bees and butterflies. You can propagate from seed in early spring in trays and transplant them later. Plant them in the sun in sandy, and well-drained soil.