Impatiens glandulifera • Class B

Policeman’s helmet is a succulent, smooth and hairless annual that ranges in height from 3 to 10 feet tall. The upright stems are hollow and have a purplish tinge. Its serrated leaves are oval to egg shaped and about 6 inches long and 3 inches wide. Flowers are white, pink or purple and resemble an old-fashioned English policeman’s helmet. The fruit is a five chambered capsule capable of producing 800 seeds each. 

It is a highly invasive, aggressive invader of wetlands, streams and moist woodlands. It displaces native plants and contributes to flooding and erosion by changing or stopping water movement. 

It is considered extremely invasive to moist, natural areas. Introduced and sold as an ornamental, this species has escaped, with distribution primarily in lowland riparian areas, which include moist forests, stream sides and roadside thickets. Policeman’s helmet is tolerant of many soil types, but requires high moisture content. It thrives in partial shade, but will also grow in full sun. 

When touched, the mature seed pods split and eject seeds up to 20 feet. 

Policeman's helmet has a shallow root system, making hand pulling very easy. Small infestations can be effectively hand-pulled or dug up. Isolated plant should be carefully removed in order to stop them from infesting a larger area. 

• Policeman’s helmet responds well to herbicides. Spot spraying with an herbicide containing the active ingredient glyphosate (Roundup Pro, Glyfos, etc.) with early season control recommended to prevent flowering, and late season application to control late-season non-flowering plants. Flowering plants sprayed with herbicide can still produce viable seed. 

• Selective broadleaf herbicides containing the active ingredients 2, 4 D and/or triclopyr (used in Crossbow, (Garlon4 or Renovate3) may also be used effectively when the plant is growing in a grassy area. Re-treatment the following year is necessary to control late-germinating plants. 

• When using herbicides, always read and follow all label instructions and obey all label precautions. (Note: pesticide product registration is renewed annually and product names and formulations may vary from year to year.) 

 Download our Flyer or visit Washington State Noxious Weed Control Board Here. Photo by Leo Michels