WSU Clark County Extension

PNW Plants Searchable, categorized images

Scotch Broom

Scientific name: Cytisus scoparius

Type:Invasive plants
Plant Requirements
Zone:6 to 9
Sun:Full sun
Plant Characteristics
Height:10 ft
Width:6 ft
Bloom:Spring flowers
Bloom Time:May to June
Bloom Color:Yellow
Additional Characteristics



Wildlife value

Description Scotch broom is considered a noxious weed in the Pacific Northwest as it outgrows all other vegetation. In Washington State it is un-lawful to transport, buy or sell all parts of this plant. It was introduced into the Pacific Northwest as an ornamental, and was used to stabilize eroded areas. It has no spread from British Columbia south into California.

Scotch broom is a deciduous shrub that grows to a height of up to 10’ and nearly as wide. It bears branched stems which are green and ridged with long division bearing small alternate leaves. The leaves are arranged in a simple or trifoliate arrangement and are un-toothed.

Yellow flowers, which bloom from May-June are 3/4” long and pea shaped and strongly scented. In the fall these flowers give rise to small pea pods which ripen black. On warm days these pods open and release the seeds within. The 1/8” long, dark green seeds have very hard seed coats which enable them to survive as many as 80 years before germinating. Seeds can be carried by animals, machinery, and people as they walk through the fields where this weed is established.

Scotch broom grows primarily in open, dry meadows and along roadsides. As the seeds can be carried by moving water new plants are often scattered around aquatic areas. The seeds and flowers contain several toxic alkaloids and should not be eaten.

None, other than humans who try to eradicate it.
For assistance, contact Dr. Charles Brun (, (360) 397-6060 5701
Computing and Web Resources, PO Box 6234, Washington State University, Pullman WA 99164-6234