Western Europe
Gorse is a woody, evergreen shrub typically growing 3–13 feet (1–4 m) tall from a multi-branched root system. Stems are hairy when young and less so as the plant ages. Leaves are alternate and three-parted when the plant is young and are reduced to scales or thick spines as the plant ages. Flowers are yellow, two-parted with an upper and lower lip, and occur either singly in leaf axils or clustered on the ends of older branches. Seed pods are hairy, turning black with age. They grow to ¾ in (2 cm) long and produce several hard, shiny, dark brown seeds.
Although goats, sheep, and wildlife will browse young growth and flowers, the negative impacts outweigh the positive because dense stands of gorse form impenetrable thickets that block access to water and more desirable forage. The spines on older growth make the plant unpalatable to grazing animals, and phenolic compounds in seeds are toxic to livestock if ingested. Gorse competes aggressively with other plants for nutrients, light, and water. It displaces native and/or more desirable species, reducing range, pasture, and commercial forest production. The high oil content of gorse foliage and seeds, and the large amount of dead growth beneath their canopies, make gorse infestations an extreme fire hazard.
Andreas, J.E., J. Price, and F.S. Grevstad. 2022. Common Gorse (Ulex europaeus): History and Ecology in North America. In: R.L. Winston, Ed. Biological Control of Weeds in North America. North American Invasive Species Management Association, Milwaukee, WI. NAISMA-BCW-2022-12-GORSE-P. https://bugwoodcloud.org/resource/files/25360.pdf