dyer's-broom

from The Century Dictionary.

• noun The plant Genista tinctoria, used to make a green dye. Also called dyeweed.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun small Eurasian shrub having clusters of yellow flowers that yield a dye; common as a weed in Britain and the United States; sometimes grown as an ornamental