WSU Extension

Hortsense

Weeds : Scotch broom : Cytisus scoparius
(revision date: 9/3/2015)

Family: Fabaceae (Leguminosae)
Cycle: Perennial
Plant Type: Broadleaf

Use Integrated Pest Management (IPM) for successful weed management.

Biology
Scotch broom is an aggressive, woody shrub reaching up to ten feet in height. The slim, angular, green branches are typically upright. Many branches are leafless. When present, the one- to three-parted leaves are rather inconspicuous. The plant produces very showy, yellow, pea-like blossoms singly or in pairs in the axils of the upper leaves. Bloom typically begins in early spring and may recur sporadically till fall. Seeds are produced in flat green pods which turn dark at maturity. The pods have obvious white hairs on the margins, but are otherwise hairless. Scotch broom spreads by seed, which can remain viable in the soil for many years. SPECIAL INFORMATION: Scotch broom is aggressive and can quickly become a serious problem if left unchecked. It is reported to be toxic to livestock. In WASHINGTON and OREGON, Scotch broom is designated as a Class 'B' noxious weed. In addition, it is on the Washington and Oregon noxious weed quarantine lists, which prohibit sale, purchase, and transport of plants, seeds, and plant parts. Management of this species may be required by law in your county. Consult your local Noxious Weed Control Board for more information.
Habitat
Scotch broom can become a problem in forest, woodlands, pastures, along roadsides, and in other open, uncultivated areas. It was introduced as an ornamental plant.

Management Options

Non-Chemical Management
  • Reduce weed infestation by handpulling weeds.
  • Careful digging is useful to manage weed populations. However, digging can carry undesirable weed seed to the surface and foster further germination.
  • However, this is very time consuming and frustrating.
Select non-chemical management options as your first choice!

Chemical Management

Apply to actively growing plants after bloom drop in spring. When using glyphosate, it is best to sever the plant at the base of the trunk, then paint the injured areas of cambium with herbicide. NOTE: Some ingredients listed here are only available in combination. Read the label carefully on combination products to make sure the product is suitable for your specific situation.

Landscape areas
  • glyphosate
Turf areas
  • triclopyr
Bare ground areas
  • glyphosate
  • products containing 2,4-D
  • triclopyr
Images
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Caption: Scotch broom flowers
Photo by: T. W. Miller
Caption: Scotch broom along highway
Photo by: T. W. Miller
Caption: Scotch broom flowers closeup
Photo by: T. W. Miller
Caption: Scotch broom fruits
Photo by: T. W. Miller
Caption: Scotch broom stand
Photo by: B.M. Johnson
Caption: Scotch broom young plant
Photo by: B.M. Johnson
Caption: Scotch broom old seed pods
Photo by: B.M. Johnson