Take a drive, walk or bike ride through Fort Stevens State Park, and at your feet is European beachgrass (more about this invasive species in a future column) along with Scotch broom and the ubiquitous shore pine among other trees. But as you can see in the photo, this landscape is relatively new, having been planted in the 1930s as part a Civilian Conservation Corps project to stabilize sand that had been blowing all over the Clatsop Plains since the construction of the South Jetty was completed around the turn of that century. It turns out that the jetty helped to accrete sand at a much faster than natural pace, causing a huge annoyance to the local population. The project has been a success, with the dunes stabilized, but its legacy includes the introduction of Scotch broom into the area.
Dane Osis, a ranger at Fort Stevens, heads the effort to control invasive species at the park, and is using a broad toolbox of methods to control the spread of Scotch broom. In addition to using the herbicide Garlon and hand pulling (Osis mentioned that an Americorps crew had just finished a project at the park), a biological control agent, the Scotch broom beetle (Bruchidius villosus), was introduced in 2007. This beetle is supposed to only eat the Scotch broom plant, and its main effect is the destruction of seeds, which the larvae eat as they develop in the seed pod. Bruchidius was introduced into the Willamette Valley in 1998, and has successfully established colonies there.
Scotch broom (Cytisus scoparius) is a member of the pea family, and is “native” to northern Africa and parts of Europe, from Sweden and the British Isles east to Ukraine. Introduced as an ornamental in the 1800s, and widely used for roadside erosion control since the early 1900s, Scotch broom has spread along the Atlantic coast from Nova Scotia to Georgia, and along the Pacific coast from British Columbia to central California.
With up to 18,000 seeds per plant, and a seed dormancy period of up to 60 years, Scotch broom is a textbook example of an invasive species. Here in Oregon, the Department of Agriculture has estimated that it costs almost $50 million a year in lost timber production, and covers about 7 million acres of western Oregon. Dave Ambrose, of the Clatsop Soil and Water Conservation District, says that Scotch broom is “uncontrollable and inextinguishable”. The district is not currently doing any work on controlling Scotch broom, except in cooperation with the project at Fort Stevens.
The North Coast Land Conservancy (NCLC), as part of habitat enhancement activities on their land, is controlling Scotch broom with mechanical methods – a combination of mowing and hand clipping and gathering. NCLC’s Scotch broom program has been successful, according to Celeste Coulter, NCLC Stewardship Director, with a noticeable reduction of flowering plants in the last 5 years.
For the average property owner, spending a little time each spring (around now) – when the brilliant yellow blooms make Scotch broom easy to spot – with some loppers can prevent the spread of this most prolific plant to unsuspecting neighbors. Just cut off all the flowering branches of the plant and compost them. For insurance, plant something near that will shade out the broom in the future.
Or you can look into using your Scotch broom to make a soothing tea, beer, salad, or even a broom! All of these have been tried in the past in the native lands of the plant, and the Plantagenet kings, who ruled England from 1154-1485, took their name from the Latin for “common broom”, another name for Scotch broom. And their namesake has been spreading its seeds across the world since!