New Hope for Scotch Broom Control

by John Woolley

Tourists ask if the brilliant yellow flower along the road is Washington’s State Flower. It is so prolific here. What do we say in reply?

Scot’s (or Scotch) broom is an invasive plant, or migrant, from Europe. French broom, Italian broom and Spanish broom are also Cytisus species. These species have been managed by humans for centuries on the Eurasian continent, as fodder or stubble in classic pasture farming where sheep, goats, and cattle are abundant, and broom therefore is not. Brought to North America for forage and highway embankment stabilization, without sheep and goats to keep it in check, Scot’s broom has a direct impact on our environment and economy. Researchers report a range of impacts due to interference with nutrient availability for other plants, allowing broom to compete successfully and become dominant. Oregon reports losses of $40 million annually in state land forest production alone due to Scot’s broom. By replacing native plant communities in open spaces, forests, and on river bars, Scot‘s broom displaces habitat for wildlife and is documented to stop literally the natural succession of species into mature forest stands. While broom can eventually be shaded out by trees, the seeds last up to 80 years, and harvest rotations are down to 50. With up to 12,000 seeds per plant, broom comes back with a vengeance after harvest, impacting the growth of the next forest stand and understory species.

Broom has likely been with each of us since childhood, but there’s a lot more of it now and the yellow blaze in spring continues to spread. Power lines and highways are corridors that broom travels, before spreading into adjacent lands—federal, state, county, industrial, and private. Addressing broom and its impacts across the Olympic Peninsula and on the San Juan Islands is the focus of a new Scotch Broom Working Group, made up of more than 25 concerned citizens, groups, agencies and tribes. In mid-December 2013, OFCO board member Jill Silver, of 10,000 Years Institute, called the group’s second meeting to order. The group’s mission is a common sense, cost-effective, collaborative approach to controlling the plant in western Washington (with the goal of eventual elimination).

Getting the public’s attention is the key. One of the group’s projects is to get funding for a statewide analysis of the economic costs of noxious weeds, including broom, on the environment, resource industries such as forestry and agriculture, and the economy. Local noxious weed programs do exist at the county level, but with little funding, relying on volunteers to get broom pulled. The state Noxious Weed Control Board has a very helpful booklet regarding native plant alternatives to replace aggressive non-native plants and shrubs. They invite your calls and emails.

Remember the basics for your own use: Cut or pull Scot’s broom stems before flowering in spring. You can simply let it lie in place or stack it. With enough moisture, it will decompose in a year. Otherwise pay heed to broom disposal programs that will be forthcoming, like covered loads to incinerators. If you are thinking of giving broom eradication a try, remember to contact the Washington Department of Transportation to adopt a highway section. Senior high school projects and community volunteer projects are also an option. Chat up a proposal with your friends and work on your Google map skills.

Let’s get serious about doing something. Start with making sure that the nurseries you visit are not selling Scot’s broom or other noxious plants.