It is an alkaloid and can be extracted from scotch broom. Invasive Scotch Broom has taken over many areas. Some of these include yellow starthistle and scotch broom. Plants containing cytisine, including the scotch broom and mescalbean, have also been used recreationally. Scotch broom has become an ecologically damaging invasive species. Several noxious weeds have also been identified, including gorse, Scotch broom, blackberries, and thistles. He introduced what is now considered a noxious, invasive plant, Scotch broom, to the island. It is known in much of the pacific northwest as Scotch broom.