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Scotch broom (Cytisus scoparius)
ODA rating: B
 
USDA Symbol: CYSC4
Oregon Scotch broom distribution
 
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  Images courtesy of Eric Coombs, Oregon Dept. of Agriculture.  
 
If images are downloaded and used from the ODA web site please be sure to credit the photographer.
 
Description
Perennial; blooms April to June. Grows 3 to 10 feet tall. Evergreen shrub with many slender, erect, dark green angled branches with small, simple leaves. Abundant small, yellow, pea-shaped flowers. Easily confused with Spanish broom. Spanish broom (S. Junceum) has round stems, very few leaves, and larger yellow flowers.

 
Impacts
Scotch broom is a pioneer species known to displace native plant species and increase the costs of timber production. It readily invades disturbed sites, natural areas, dunes and public and private forest lands. Maintenance of rights-of-way, facilities, parkland and private property costs millions of dollars each year because of rapid growth of young plants and the plant's persistent nature. Seeds of Scotch broom are long-lived (50 years plus) and mature plants are prolific seed producers, establishing persistent seed banks requiring long-term management objectives. The largest costs attributed to scotch broom come from additional inputs needed to establish trees in commercial and public timberlands. It is estimated that Scotch broom costs Oregon $47 million dollars annually in lost timber production.

 
Distribution in Oregon
The first documented site in Oregon was 1892 in Benton County.

  Biological controls
Three biological control agents, a beetle, a seed weevil and a twig miner are approved for release and have been established in Oregon.

Bruchidius villosus
Exapion fuscirostre
Leucoptera spartifoliella