Aromatic herb used since the Middle Ages as an insect repellent. It is used to expel worms in animals (including humans), repel fleas and bed bugs and to delouse parasites on horses and dogs. Dried, it will also repel moths and ants in stored goods. It has green fern like leaves with attractive heads of yellow button flowers. A creeping rootstock habit makes it easy to divide in autumn or spring. Chilling seeds for 2 weeks will aid germination.