Vectors of Spread:
General: Scotch Broom can be identified by its small, bright, pea-like yellow flowers and its rigid woody stems.
Flowers: Small, bright, pea–like, yellow flowers; they can also have a red centre. Scotch Broom flowers are about 2 cm long and have 5 petals. They occur in groups of 2 – 3 along the stems.
Stem: Rigid and woody stems. Stems are green and photosynthetic. Young branches have 5 green ridges with hairs. Stems become smooth as they mature. Mature plants can be between 1 – 3 m tall.
Leaves: Lower leaves are stalked and composed of 3 leaflets, while upper leaves are single and un-stalked. Leaves are egg-shaped to oblong and 5 – 20 mm long, and may fall off early in the year, leaving stalks bare.
Seeds: Yellow flowers mature to form flattened seedpods (legume-like) that change from bright green to brown or black before they dry out and split. Each pod contains between 5 – 12 seeds.
Roots: Has a deep, branched taproot.
Gorse (Ulex europaeus) is a (very!) thorny shrub with inch-long sharp spines that may grow up to 1.8 m tall. The flowers, similarly to Scotch Broom, are yellow and pea-like; however, the flowers are around 0.8 cm long and cluster on the ends of the branches.
St. John’s Wort (Hypericum perforatum) is a perennial that grows to about 1 m in height. It has showy, bright yellow flowers with 5 petals that turn rusty red when they mature. It prefers dry, sandy soils and full sun.
Spanish Broom (Spartium junceum) is another invasive Broom plant with yellow flowers. You can spot the difference by their stems: Spanish Broom stems are round, whereas Scotch Broom stems are ridged. Spanish Broom also flowers later in the year.
Bird’s-Foot Trefoil (Lotus corniculatus) is a perennial that grows 60cm tall. It has bright yellow flowers and grows along roadsides and disturbed areas.
Habitat and Origin
Scotch Broom was brought to North America from Scotland as a garden ornamental by Captain Walter Grant and planted on Vancouver Island in Sooke. Amazingly, Captain Grant only brought over 3 Scotch Broom seeds with him in the 1850’s and the plant has managed to spread and thrive across Vancouver Island and many areas of BC at an incredible rate.
Scotch Broom grows in open, disturbed sites at low elevations. It is found along roads, railway lines, dry fields, rocky slopes, and utility right-of-ways. It thrives in well-drained, sandy soil and full sunlight, though it will also tolerate shaded areas. Scotch Broom is a highly aggressive spreader and can quickly cover fields, meadows and any deforested areas.
Propagation and Vectors of Spread
Scotch Broom can spread by seed as well as by lateral bud growth. Each seedpod contains between 5-12 seeds. Mature plants can produce up to 3,500 seedpods, and each seed can stay viable in the soil for up to 60 years.
When seedpods dry, they split and can expel seeds up to 5 m away. The seeds are also dispersed by wind, vehicles, animals, humans and in soil.
Economic and Ecological Impacts
- Dense thickets create fire hazards due to resinous sap in stems.
- Dense thickets also limit the movement of large animals.
- Displaces native plant and animal species.
- Outshades conifer seedlings.
- Alters nitrogen composition of soil.
- Toxic to livestock is ingested.
- Obstructs sight lines on roads, railways and utility right-of-ways, resulting in increased maintenance costs for removal.
- Reduces forage for livestock, resulting in reduced production.
What Can I Do?
The best approach to controlling the spread of Scotch Broom is PREVENTION.
Learn to identify Scotch Broom: Use the images presented on this profile page.
What to do if you spot it: You can report any Scotch Broom sighting by clicking here.
- Regularly monitor properties for weed infestations.
- Ensure soil and gravel is uncontaminated before transport.
- Quickly re-vegetate disturbed areas with fast-growing competitive, native plants can limit growth of Scotch Broom and is a fundamental tool to limit its spread.
- Minimize soil disturbance in area surrounding infestation.
- Ensure plants (particularly flowering heads or root fragments) are bagged or covered to prevent spread during transport to designated disposal sites (e.g. landfill).
- Plant Scotch Broom in a garden, no matter how well-contained its enclosure may seem.
- Move soil that has been contaminated with Scotch Broom.
- Unload, park, or store equipment or vehicles in infested areas; remove plant material from any equipment, vehicles, or clothing used in such areas and wash equipment and vehicles at designated cleaning sites before leaving infested areas.
- Mow or weed-whack Scotch Broom plants, as the fragments can propagate as new colonies. Frequent mowing may also accelerate shoot development, leading plants to spread laterally from the parent plant.
- Compost Scotch Broom, especially the seeds!
Grazing by goats and chickens has been shown to reduce infestations.
- Small seedlings (less than a pencil width) can be hand-pulled when the soil is moist. Larger plants must be cut down at the base of the stem before they begin to flower.
- Due to Scotch Broom’s need for sunlight to photosynthesize, covering the newly-cut stem with soil, moss or plastic will help prevent regrowth.
- Commonly used herbicides include triclopyr, imazapyr, aminopyralid and glyphosate, applied alone or in combination with 2,4-D.
- Herbicides can be applied from spring to late summer using selective spot spraying, basal stem injection, or cut surface application.
We recommend that any herbicide application is carried out by a person holding a valid BC Pesticide Applicator Certificate. Before selecting and applying herbicides, you must review and follow herbicide labels and application rates; municipal, regional, provincial and federal laws and regulations; species-specific treatment recommendations, and site-specific goals and objectives.
Several species of seed-feeding beetles have been released into Scotch Broom populations south of the BC-Washington border. Biological control agents have not yet been shown to reduce Scotch Broom density in established populations, but do help to reduce spread, especially in combination with other removal efforts.
Coastal Invasive Species Committee, Scotch Broom, https://www.coastalisc.com/scotch-broom/
Electronic Atlas of the Flora of British Columbia, Spartium junceum, https://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Spartium+junceum
Electronic Atlas of the Flora of British Columbia, Cytisus scoparius, https://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Cytisus%20scoparius
Invasive Species Council of BC, Scotch Broom, https://bcinvasives.ca/invasives/scotch-broom/
Invasive Species Council of BC, TIPS Factsheet, https://bcinvasives.ca/documents/Scotch_Broom_TIPS_Final_08_06_2014.pdf
King County Noxious Weed Control Program, Best Management Practices for Spanish Broom, https://www.nwcb.wa.gov/images/weeds/Spanish-Broom-Control_King.pdf
Nature Conservancy of Canada, Scotch Broom, https://www.natureconservancy.ca/en/what-we-do/resource-centre/invasive-species/scotch-broom.html
University of California Integrated Pest Management Program, Brooms, https://ipm.ucanr.edu/PMG/PESTNOTES/pn74147.html
University of California Weed Research & Information Centre, “Spanish Broom” in Weed Control in Natural Areas in the Western United States, https://wric.ucdavis.edu/information/natural%20areas/wr_S/Spartium.pdf
Washington State Noxious Weed Control Board, Scotch Broom, https://www.nwcb.wa.gov/weeds/scotch-broom