Other Common Names: ornamental jewelweed
Weed class: B
Year Listed: 1999
Native to: India and western Himalaya
Is this Weed Toxic?:
not known to be
This plant is also on the Washington State quarantine list. It is prohibited to transport, buy, sell, offer for sale, or distribute plants or plant parts of quarantined species into or within the state of Washington or to sell, offer for sale, or distribute seed packets of seed, flower seed blends, or wildflower mixes of quarantined species into or within the state of Washington. Please see WAC 16-752 for more information on the quarantine list. For questions about the quarantine list, contact the Washington State Department of Agriculture's Plant Services Program at (360) 902-1874 or email PlantServices@agr.wa.gov.
Why Is It a Noxious Weed?
It is considered extremely invasive to moist, natural areas. Introduced and sold as an ornamental, this species escaped with distribution primarily in lowland riparian areas which include moist forests, stream sides and roadside thickets.
How would I identify it?
Policeman's helmet is an herbaceous annual that is succulent and glabrous (smooth and hairless), and it can range from 3 feet to 10 feet tall.
Flowers are irregular and the color ranges from white to all shades of pink purple. They have 5 petals (2 fused), 3 sepals (2 fused), and 5 stamens. The shape resembles a British policeman's hat, hence the common name.
Leaves are alternate, opposite or whorled and usually have 3 leaves to a node. The shape is oblong to ovate to elliptic. They are about 6 inches long and half as wide with sharply toothed margins.
Stems are hollow, upright and have a purplish tinge.
Fruit Seed Description
Flowers form capsules that contain small seeds (3 mm).
May Be Confused With
There are other native and non-native Impatiens species in Washington State. Plants can be best identified when they are in flower. See the key in Peter Zika's article "Jewelweeds and touch-me-nots (Impatiens, Balsaminaceae) in the Pacific Northwest of North America" in the Botanical Electronic News. If you need help with plant identification, please contact your county noxious weed coordinator.
Where does it grow?
Policeman's helmet is partially shade tolerant and is found in lowland, riparian areas which include moist forests, stream sides and roadside thickets. Please click here to see a county level distribution map of Policeman's helmet in Washington.
How Does it Reproduce?
Policeman's helmet reproduces by seed. Each plant can produce up to 800 seeds. The seeds are ejected over 20 feet from the capsule. Seeds can germinate underwater and can be viable for 18 months or more.
How Do I Control It?
An annual with a shallow root system, this plant pulls up easily. A seed bank is present with 2 year viability - follow up control is recommended. Populations may be mowed but need to be monitored in case mowed plants resprout later in the season. Remove and carefully dispose of flower and seed heads prior to mowing.
Sheep and cattle graze the whole plant in Britain.
Please refer to the PNW Weed Management Handbook, or contact your county noxious weed coordinator. It does respond to herbicide, 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.
For More Information
See our Written Findings for more information about policeman's helmet (Impatiens glandulifera).
Botanical Electronic News Impatiens article by Peter Zika (scroll down) "JEWELWEEDS AND TOUCH-ME-NOTS (IMPATIENS, BALSAMINACEAE) IN THE PACIFIC NORTHWEST OF NORTH AMERICA"
Cowlitz County NWCB Fact Sheet on policeman's helmet
Whatcom County NWCB Fact Sheet on policeman's helmet
King County NWCB Fact Sheet on policeman's helmet
Clallam County NWCB Fact Sheet on policeman's helmet
Jefferson County NWCB Fact Sheet on policeman's helmet
Control Options for policeman's helmet from King County NWCB