A perennial, evergreen shrub, Spanish broom can at first glance be mistaken for Scotch broom (Scot’s broom) but is distinguished by its fragrant flowers and round stems. Spanish broom can grow from 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 stocks.

The leaves this plant does have 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 is shaped like a spear head and hairs are present on the lower surface. Flowers grow in clusters at the branch ends on stalks that can be 18 inches long. Fragrant, bright yellow and pea-shaped, approximately 1-inch-long, the flowers grow in clusters at the branch ends. Spanish broom flowers from July to October. It reproduces by seed; one plant can produce up to 10,000 seeds in one season. Seeds remain viable in the soil for at least five years.

Spanish broom is a noxious weed because of its prolific seed production and aggressive replacement of native plants. Spanish broom plants render rangeland and grasslands worthless. It is poisonous to humans, horses and livestock. Dense stands of Spanish broom impede the movement of wildlife and it is considered a potential fire hazard.

Locations of Spanish broom are still limited in Washington, and it is listed as a Class A noxious weed. Class A noxious weeds are mostly newcomers to Washington, and are generally rare. The goal is to completely eradicate them before they gain a foothold. Landowners are required, by law, to completely eradicate these plants. Thus, eliminating the seed source and spread of plants before they become more widespread.

Eradication means getting rid of the plants altogether, including the roots. For small infestations of this noxious weed, the entire plant should be removed and sealed into a plastic trash bag and disposed. When possible, allow bagged plants to rot in a sunny location, then dispose of in regular trash.

If you have questions or concerns about this or other noxious weeds, please contact the Grant County Noxious Weed Control Board at (509) 754-2011, Ext. 4710 or www.grantcountyweedboard.org.