Spanish Broom
Spartium junceum

History and Impact

A perennial, evergreen shrub, spanish broom can be mistaken for Scotch broom (Scot's broom) but is distinguished by its fragrant flowers and round stems. Spanish broom is a noxious weed because of its prolific seed production and aggressive replacement of native plants. As a Class A noxious weed, its eradication is required in King County and throughout Washington State. Although Spanish broom was formerly sold in Washington State as an ornamental, this is no longer legal because it is on the state's prohibited plants list.

Biology and Morphology

Spanish broom can grow 6 to 10 feet tall, generally prefers low-nutrient, rocky or sandy soils in full sun, and is most often found escaping into disturbed areas such as roadsides, exposed hillsides, trails, parks and vacant lots. The mainly leafless stems branch off at the top, ending with clusters of flowers on leafless racemes (stalks). The leaves are simple and one-parted (as compared to the three-parted leaves of Scot's broom) and are alternate and less than 1 inch long. The leaf shape is linear to lanceolate, and hairs are present on the lower surface. Fragrant, bright yellow and pea-shaped, approximately 1 inch long, the flowers grow in clusters at the branch ends on stalks that can be 18 inches long. They can bloom from July to frost. The fruits are hairy seed pods, flat and linear, up to 3 inches long. Spanish broom spreads by seed.

Spanish broom photos - click thumbnail for larger image

For information on Spanish broom identification and control, please download our Spanish broom weed alert (166 KB Acrobat file).

For more information about Spanish broom, please see the WA State Noxious Weed Control Board written findings.

For information on controlling Spanish broom in King County, Washington please read the Spanish Broom Best Management Practices (155 KB Acrobat file).

If you find Spanish broom in King County, please notify us through our online infestation form.

To find out where we have records of this weed in King County, use our interactive noxious weed map and search for Spanish broom.