Photo credit: John M. Randall, The Nature Conservancy, Bugwood.org
Management Strategy
Squamish
Whistler
Pemberton
Vectors of Spread
ID Characteristics
General: Gorse is a dense, evergreen, thorny shrub.
Flowers: Pea-like, bright yellow flowers that grow in clusters at the end of branches. Flowers are 1.5 – 2 cm long.
Stem: Gorse grows in a single upright stem, which is heavily branched. It grows 1 – 3 m tall and up to 6 m wide. Stems are five-angled and sparsely hairy. Gorse plants grow outwards, forming an area of dry, dead vegetation in their centre.
Leaves: Young plants have compound leaves composed of 3 leaflets. In mature plants, these leaflets evolve into scales or spines. Spines are dark green, branched and grooved, 1.5 – 2.5 cm long.
Seeds: The black, hairy seedpods are 1.5 – 2 cm long.
Roots: Shallow adventitious roots with a deep taproot. Gorse forms nitrogen-fixing root nodules, which allow it to colonize nutrient-poor soils.
Similar Species
Photo credit: B. Brett
Invasive:
Scotch Broom (Cytisus scoparius) also has yellow pea-like flowers, but it has small, simple leaves rather than Gorse’s spine-like leaves.
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.
Photo credit: B. Brett
Spanish Broom (Spartium junceum) is another invasive Broom plant with yellow flowers. Like Scotch Broom, its leaves are round, unlike Gorse which has spine-like leaves. You can spot the difference between Spanish and Scotch Broom by their stems: Spanish Broom stems are round, whereas Scotch Broom stems are ridged. Spanish Broom also flowers later in the year.
Habitat & Origin
Gorse is native to Western Europe. It was first introduced as an ornamental in south coastal Oregon in the late 19th century and has since spread widely in coastal areas from California to British Columbia.
Gorse thrives in poor, dry soils and high heat. It often becomes established on non-tillable land and in inaccessible places like fence rows and river banks. Given its preference for sunny clearings, it is usually found in sandy or rocky areas, roadsides, fields and pastures, bluffs, cutblocks and cutbanks.
How it Spreads
Gorse spreads primarily by seed. One mature plant can produce up to 8,000 seeds annually, and seeds can remain viable in the soil for up to 40 years, leading to the rapid formation of a seed bank. This is only compounded by the plant’s long lifespan (up to 45 years), with the first 15 being years of rapid growth. Gorse can also reproduce vegetatively by cuttings.
Gorse’s exploding seedpods are key to the plant’s spread, as the seeds can land several meters from the parent plant. Seeds are also easily spread by ants, animals and machinery. Since Gorse grows beside the ocean, water is a common vector of spread. Lastly, this plant may also resprout from cut stumps.
Impacts
Ecological:
- Creates impenetrable thickets that impede the movement of wildlife.
- Crowds out all other vegetation and releases toxins into the soil, causing a decrease in biodiversity, a loss of habitat and decreased forage for wildlife.
- Causes erosion, especially on steep slopes.
- Increases fire hazard, as Gorse contains volatile oils and produces large amounts of litter.
Economic:
- Sharp thorns restrict recreational activities.
- Dense patches can hinder the re-vegetation of harvested areas and the recreational use of land.
- Increases cost of forestry practices.
Stop the Spread
Gorse is not yet found in the Sea to Sky region, but is found in neighbouring areas and may arrive here soon. The goal is to prevent Gorse’s introduction by focusing on education and awareness. If prevention fails, the goal will become immediate eradication following the proposed SSISC EDRR protocol.
Learn to identify Gorse: use the images presented on this profile page.
What to do if you spot it: You can report any Gorse sighting by visiting our reporting page.
DO:
- 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 the growth of Gorse and is a fundamental tool to limit it.
- Minimize soil disturbance in the area surrounding the 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).
- Remove plant material from any equipment, vehicles, or clothing used in infested areas and wash equipment and vehicles at designated cleaning sites before leaving the area.
DO NOT:
- Do not plant Gorse in a garden, no matter how well-contained its enclosure may seem.
- Do not move soil that has been contaminated with Gorse.
- Do not mow or weed-whack Gorse 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.
Control
Control
Mechanical Control:
- Hoeing or digging up small infestations, including all plant roots, may be effective; re-sprouting can occur from any remaining root portions.
- Follow-up treatments to remove new seedlings (from severed roots or the seed bank) will be required.
- Cutting plants alone is not effective in eradicating Gorse; herbicide must be applied to cut stumps.
- If you choose to mow Gorse, be prepared to do so repeatedly to deplete plant root reserves, as a single mowing will promote vegetative growth.
Chemical Control:
- Herbicide treatment is most effective after bloom drop; the treatment should be followed by seeding or replanting native species to prevent re-infestation from the seed bank.
- Glyphosate, dicamba, triclopyr, 2,4-D and metsulfuron methyl have been proven effective.
- Herbicides, especially triclopyr and glyphosate, can be applied in a few ways, including foliar application, basal cut stump, cut stump and basal bark.
- Lastly, picloram is also effective in controlling Gorse, but it is not suitable for wet, coastal soils.
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.
Biological Control:
There is no biocontrol available for Gorse in BC.
Sea to Sky Distribution
Gorse Factsheet
Additional Resources
