By East Kootenay Invasive Species Council

Scotch broom (English broom) is an escaped garden plant introduced from Europe that easily invades sunny, disturbed sites such as rangelands, roadsides, and areas of recent logging.

Scotch broom can increase the intensity of wildfires, obstruct sightlines along roads, and crowd out native plants that animals depend on. A mature plant can live up to 25 years and produce seeds that can survive in the soil for 30 years.

Scotch broom is designated as a Regional Containment/Control species by the BC Provincial Priority Invasive Species List, however Scotch broom is not yet in the East Kootenay, so this is considered a high priority – please report any suspected plants!

How to Identify:

Scotch broom is a woody shrub that typically grows one to three metres tall with distinctive five-angled stems. Its bright yellow, pea-like flowers often feature a small red marking in the center and grow along the stems rather than just at the tips. The plant’s leaves vary, with the lower ones made up of three small leaflets on stalks, while the upper leaves are simple and unstalked. After flowering, Scotch broom produces flat, hairy seedpods that start out green before turning brown to black as they mature. It can be mistaken for Spanish broom, another non-native species, but Spanish broom’s flowers are clustered at the very tips of stems, unlike Scotch broom’s flowers that are spread along the branches.

Impacts:

Economic: Invades rangeland, replacing forage plants, and can be a serious competitor to conifer seedlings. Douglas fir plantation failures in Oregon and Washington have been credited to infestations by this plant. High density infestations can: (i) increase wildfire fuel loads, thereby escalating wildfire intensity; and (ii) obstruct sight lines on roads, resulting in increased maintenance costs for removal.

Ecological: Can produce dense, impenetrable thickets that may be impacting Garry oak woodlands in southwestern BC and limiting the movement of large animals, wild or domestic. Possesses photosynthetic stems to enable year round.

Management Strategies:

Mechanical: Cut plants below ground level before flowering and seed set, or hand-pull smaller stems in late spring. Due to strong seed banks and resprouting, treatments must be repeated for three to five years. Minimize soil disturbance, as it can encourage regrowth; if pulling causes disturbance, cut stems as close to the ground as possible. Burning is not effective since seeds germinate after fire.

Biocontrol: No agents are currently approved in B.C., though some U.S. beetles have moved north and are being monitored. Grazing by goats and seed consumption by chickens can help reduce infestations.

Chemical Control: Herbicide use must follow site-specific goals and legal requirements. Options include triclopyr, glyphosate, or mixes with aminopyralid or 2,4-D, applied through foliar, cut stump, basal bark, or injection methods. Spot treatments are recommended to minimize non-target impacts. Pesticide use on Crown land must follow an approved Pest Management Plan under the Integrated Pest Management Act.

Learn more here.

East Kootenay Invasive Species Council photos

The East Kootenay Invasive Species Council works to minimize the threat of invasive species that impact the environment, the economy and human health in the East Kootenay region of B.C., and we couldn’t do it without you! as a non-profit, we rely on grant funding and the generous support of our community to operate. Your donation will help us continue to protect the East Kootenay from invasive species. Donate here.

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