The Collaborative International Dictionary of English v.0.48:

dyer's broom \dyer's broom\, dyer's-broom \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]

The Collaborative International Dictionary of English v.0.48:

Broom \Broom\ (br[=oo]m), n. [OE. brom, brome, AS. br[=o]m; akin
   to LG. bram, D. brem, OHG. br[=a]mo broom, thorn?bush, G.
   brombeere blackberry. Cf. Bramble, n.]
   1. (Bot.) A plant having twigs suitable for making brooms to
      sweep with when bound together; esp., the Cytisus
      scoparius of Western Europe, which is a low shrub with
      long, straight, green, angular branches, minute leaves,
      and large yellow flowers.
      [1913 Webster]

            No gypsy cowered o'er fires of furze and broom.
                                                  --Wordsworth.
      [1913 Webster]

   2. An implement for sweeping floors, etc., commonly made of
      the panicles or tops of broom corn, bound together or
      attached to a long wooden handle; -- so called because
      originally made of the twigs of the broom.
      [1913 Webster]

   Butcher's broom, a plant (Ruscus aculeatus) of the Smilax
      family, used by butchers for brooms to sweep their blocks;
      -- called also knee holly. See Cladophyll.

   Dyer's broom, a species of mignonette (Reseda luteola),
      used for dyeing yellow; dyer's weed; dyer's rocket.

   Spanish broom. See under Spanish.
      [1913 Webster]