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Biology, Ecology, and Management of Scotch Broom (Cytisus scoparius L.)

Invasive Species Technical Note Number MT-29

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Invasive Species Technical Note Number MT-29 (PDF; 127 KB)

September 2010

Melissa Graves, MSU Extension Integrated Pest Management and Weeds Specialist, Department of Land Resources and Environmental Sciences, Bozeman, Montana
Jane Mangold, MSU Extension Invasive Plant Specialist, Department of Land Resources and Environmental Sciences, Bozeman, Montana
Jim Jacobs, Invasive Species Specialist, NRCS, Bozeman, Montana

Abstract

Scotch broom (see Figure 1), a member of the pea family (Fabaceae), is a highly invasive perennial shrub reaching up to 13 feet (4 meters) in height.

Picture of Scotch broom colony.
Figure 1. Scotch broom colony (Photo courtesy of J.S. Peterson, USDA Plants Database, 2009).

Young plants have green stems that become woody as the plant matures. The deciduous leaves are alternately arranged on the stem and ones lower on the plant have three leaflets per leaf similar to a clover leaf. The leaves are not divided into three leaflets higher on the plant, but are instead simple. The flowers, which resemble a pea flower, are bright yellow, but may occasionally be tinged with red or purple. Blossoms are typically found in the leaf axils or at the branch tips. Scotch broom spreads rapidly and its rapid growth rate allows it to crowd out other plant species, especially in disturbed sites, pastures, roadsides, and open woods. Control of Scotch broom is difficult once it becomes established, with repeated treatments often required to manage populations. Scotch broom is currently limited to Sanders and Lincoln Counties in northwestern Montana, therefore prevention and early detection are key to its management.

Identification
Plant Biology
Management Alternatives
References

Harrington, T.B. 2009. Seed germination and seedling emergence of scotch broom (Cytisus scoparius). Weed Science. 57: 620-626.

Paynter, Q., P.O. Downey, and A.W. Sharp. 2003. Age structure and growth of the woody legume weed Cytisus scoparius in native and exotic habitats: implications for control. Journal of Applied Ecology. 40: 470-480.

Peterson, D.J. and R. Prasad. 1998. The biology of Canadian weeds. 109. Cytisus scoparius (L.) Link. Canadian Journal of Plant Science. 78: 497-504.

Potter, K.J.B., D.J. Kriticos, M.S. Watts, and A. Leriche. 2009. The current and future potential distribution of Cytisus scoparius: a weed of pastoral systems, natural ecosystems, and plantation forestry. Weed Research. 49: 271-282.

Wildland Fire in Ecosystems: Fire and Nonnative Invasive Plants. 2008. United States Department of Agriculture. Rocky Mountain Research Station. General Technical Report RMRS-GTR-42-Volume 6.

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Last Modified: 11/10/2011