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Noxious weeds

King County, Washington

To offer a suggestion or report an error on the King County Noxious Weeds website, please contact Sasha Shaw, education specialist.

Spanish broom
Spartium junceum

Spanish broom plantsA 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.

Legal status in King County, Washington

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 this species is on the Washington quarantine list (known as the prohibited plants list) (external link) and it is prohibited to transport, buy, sell, offer for sale, or to distribute plants or plant parts, seeds in packets, blends or "wildflower mixes" of this species, into or within the state of Washington.

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). Spanish broom flower and stem - click for larger imageThe 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.

Additional information on spanish broom

What to do if you find this plant in King County, Washington

Please notify us if you see spanish broom growing in King County. Our program staff can provide the property owner or appropriate public agency with site-specific advice on how best to remove it. We map all known locations of regulated noxious weeds such as spanish broom in order to help us and others locate new infestations in time to control them.

Spanish broom photos - click thumbnail for larger image

Spanish broom - Spartium junceum - click for larger image Spanish broom - Spartium junceum - click for larger image Spanish broom - Spartium junceum - click for larger image Spanish broom - Spartium junceum - click for larger image Spanish broom - Spartium junceum - click for larger image
Spanish broom - Spartium junceum - click for larger image Spanish broom - Spartium junceum - click for larger image Spanish broom - Spartium junceum - click for larger image Spanish broom - Spartium junceum - click for larger image

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Related information

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Program offices are located at 201 S. Jackson St., Suite 600, Seattle, WA 98104. To contact staff, see the Noxious Weed Control Program Directory, send an email, or call 206-477-WEED (206-477-9333).