Scotch Broom

Common Name: Scotch Broom
Scientific Name: Cytisus scoparius
Origin: Northern Africa and Europe

Description

Scotch broom is a shrub that grows up to 10 feet tall and whose green branches are sharply angled with five ridges. Young plants have hairy stems, while mature plants are hairless. Along the stem, small, pea-like, yellow flowers bloom from late May to June. The flowers give way to blackish-brown seed pods with hairs along the seams that explode when mature. Scotch broom leaves are small, alternately arranged, oblong and occur in groups of three.

Habitat

Scotch broom tolerates a wide range of conditions, but is most often found in open, disturbed areas including along roadsides, forest edges, river banks and fields.

Threat

Scotch broom fixes nitrogen allowing it outcompete native plants in nutrient deficient soils. Scotch broom also forms dense thickets that displace native plants and does not provide good forage for wildlife. Its seeds can survive in the soil for more than 30 years, allowing seed banks to accumulate and making management challenging.

Management

Small infestations should be controlled manually or mechanically before seed pods mature and will require several years of follow-up given this plant’s deep roots and ability to resprout. Larger infestations may be treated with herbicide using cut-stump, foliar or basal bark applications.

Regional Distribution

Early Detection

WNY PRISM Priority

Tier 2 – Eradication

Invasive Species Priorities – Tier Chart

Pathways

Scotch broom was introduced to North America as an ornamental plant and for erosion control. It produces numerous seeds which are easily spread by natural activities including flowing water and ants, and can be spread by human disturbance including road work and mowing. Mature seedpods also open explosively launching seeds up to 20 feet away.

Additional Resources

National Park Service Species Profile

USDA Invasive Species Profile

King County, WA Best Management Practices