Definition of French broom in English:

French broom

noun

  • (Originally) †any of several southern European brooms (obsolete); (in later use) specifically the yellow-flowered species Genista monspessulana, native to the Mediterranean but introduced elsewhere, and now considered an invasive weed in parts of North America and Australia.

Origin

Mid 16th century; earliest use found in William Turner (d. 1568), naturalist and religious controversialist.