Arresting the Spread of Policeman’s Helmet

Don’t be fooled by the attractive flowers of the Policeman’s Helmet! This invasive weed is gaining a foothold in the Sandy River Basin, but there is hope through a grassroots effort to stop it!

Organized efforts against Policeman’s Helmet began a couple of years ago, spearheaded by the Sandy River Basin Watershed Council at two sites. Funding from the Clackamas County Soil and Water Conservation District helped the Council double their work to include four sites.

Between late May and early August, volunteers logged 400 hours hand-pulling 3,800 plants that would have produced millions of seeds. Volunteers included local fishing groups and the Northwest Youth Corps. Alert community members who had learned to identify this weed reported these weed patches, allowing volunteers to remove them along streams and in residential neighborhoods. Both private and public land received the benefit of these weed warriors.

Impatiens glandulifera, also known as Policeman’s Helmet, can reach heights of up to eight feet. It produces numerous seed pods that explode when dry, propelling seeds up to 20 feet away. This aggressive plant thrives along streams and in disturbed areas. Due to large seed production, ability to disperse, and high germination rate, Policeman’s Helmet can colonize and establish mature stands within three years. These thick stands dominate and displace native vegetation that local wildlife depends upon for food and shelter. In the fall, when the weather turns cold, this annual plant dies down, leaving bare soil that erodes during heavy winter rainstorms.

The Sandy River Basin Watershed Council plans to continue control on all four work sites. The Council is also working toward including new sites such as Oxbow Park along the lower Sandy River, where Policeman’s Helmet was recently discovered.

The Clackamas County Soil and Water Conservation District is also concerned about new infestations recently identified along the Clackamas River. These occurrences are a high priority our WeedWise program. If you see this plant, please report it to the Oregon Invasive Species Hotline or contact the Clackamas County SWCD at 503-210-6000.


Clackamas SWCD