Wikipedia
Strewing herb
Strewing herbs are certain kinds of plants that are scattered (strewn) over the floors of dwelling places and other buildings. Such plants usually have fragrant or astringent smells, and many also serve as insecticides or disinfectants. Their use was widespread in England during the Middle Ages through to the 18th century.
Usage examples of "strewing herb".
As a kitchen herb it has gone out of use because of its strong flavour, but on account of its aroma it was formerly employed as a strewing herb.