 Scotch Broom
Cytisus scoparius (L.) Link
Family: Fabaceae
Description and Life Cycle
Scotch broom is a perennial, evergreen shrub that reproduces by
seed. Mature height is 1 – 3 m tall with stiff angled, somewhat
erect, dark green branches creating an irregular shape. Many of the
branches are leafless or have few leaves. Upper leaves are simple
(single) while lower are trifoliate (three parts). Forked tap roots
enable it to anchor in rocky shorelines and steep slopes. Bright
yellow 2.0 cm pea-like flowers appear from early April through June.
Up to eight brown seeds, 2 – 3 mm long with shiny coats, develop
within brown-black pods with hairy margins. In the soil, seeds can
remain viable for 60 years or more. Scotch broom spreads rapidly in
an open canopy along right-of-ways, trails and near streams. It is
drought tolerant, preferring infertile or rocky soils and is well
adapted to windy seashore conditions. All parts of the plant contain
small amounts of toxic alkaloids capable of poisoning livestock when
consumed. As with all plants in the Fabaceae family, it too fixes
nitrogen, however, the nitrogen does not become available until
after the plant dies.
 Biological Control Agents
References
MFR staff observations and comments
Parker, B., Miller G. and L. C. Burrill. 1998. Scotch broom, Cytisus scoparius (L.) Link. Weeds. A Pacific Northwest Extension Publication. PNW 103, reprinted October 1998.
Rees, N. E., P. C. Quimbly Jr., G. L. Piper, E. M. Coombs, C. E. Turner, N. R. Spencer, L. V. Knutson. 1996. Biological control of weeds in the west. Western Society of Weed Science.
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