policeman's helmet

Impatiens glandulifera

   

Family: Balsaminaceae

Other common names: ornamental jewelweed

Weed Class: B

Year Listed: 1999

Native to: India and western Himalaya

Toxic: not known to be

Other Legal Listings: WA Quarantine list, WAC 16-750

additional photos

 

   

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?

General Description: 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.

Flower Description: 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.

Leaf Description: 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.

Stem Description: 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: Western touch-me-not (Impatiens noli-tangere) has a similar appearance to policeman's helmet, and is found in similar habitats. If you need help with plant identification, please contact your county noxious weed coordinator.

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.
 

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 do I control it?

Mechanical Control

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.

Cultural Control

Sheep and cattle graze the whole plant, in Britain.

Herbicide Control

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 still produce viable seed.


 

For more information

 
See our Written Findings for more information about policemans helmet (Impatiens glandulifera).

Additional Photos


 
 

 


Policemans helmet flowers

 


Policemans helmet stem and leaf base

 


leaves with serrated margins

 


flowers

 


flowering stems

    

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