fleabane

noun

1. any of various composite plants, as Pulicaria dysenterica, of Europe, or Erigeron philadelphicus, of the U.S., reputed to destroy or drive away fleas.

noun

1. any of several plants of the genus Erigeron, such as E. acer, having purplish tubular flower heads with orange centres: family Asteraceae (composites)
2. any of several plants of the related genus Pulicaria, esp the Eurasian P. dysenterica, which has yellow daisy-like flower heads
3. Canadian fleabane a related plant, Conyza (or Erigeron) canadensis, with small white tubular flower headsUS name: horseweed
4. any of various other plants reputed to ward off fleas