*dyer's-broom*

n. small Eurasian shrub (Genista tinctoria) having clusters of yellow flowers that yield a dye; common as weed in England and U.S.; sometimes grown as an ornamental.
Syn. -- woodwaxen, dyer's greenweed, dyer's weed, dyer's rocket, dyeweed, greenweed, whin, woadwaxen, Genista tinctoria. [ WordNet 1.5 ]