
Policeman’s Helmet
Botanical Name:
Impatiens glandulifera
Class B Noxious Weed
General
- State quarantine laws prohibit transporting, buying, selling, or distributing plants, plant parts or seeds of policeman’s helmet.
- Aggressive invader of wetlands streams.
- The combination of dense stands, great height, and large leaves suppresses other plants and create bare patches under the policeman’s helmet canopy.
- Displaces native plants and threatens habitat.
- Competes with native plants for pollinators such as bumblebees, reducing native plant’s ability to set seed.
- Seeds were sent from the Himalayan region of northern India and Kashmir to Europe in the mid-19th century as garden ornamentals.
Identification
- Hollow-stemmed annual plant ranging from 3 to 8 feet in height
- Plant stems are smooth in texture, multi-branched, reddish in color, and have large swollen nodes and glands.
- Flowers resemble an English policemna’s helmet. Flower color ranges from white, pink, red and purple and are arranged in sparse cluster from the leaf axils.
- Large simple leaves are rounded, toothed, and can be opposite or whorled in groups of three.
Habitat
- Tolerant of many soil types, prefers moist soils, although not necessarily standing water.
- Can grow in full sun as well as partial shade.
- Plants can be found in lowland, riparian areas which include moist forests, stream sides, wetlands and roadside thickets.
Reproduction and Spread
- Reproduces by seed but can also spread vegetatively.
- Annual plant, flowers from July until September.
- Seed production begins in late summer through fall until first frost (August – September).
- Single plant can produce from 800 to 2500 seeds.
- Seeds are dispersed from mature capsules, which upon the lightest tough explode ejecting seeds up to 20 feet. The seeds over winter in soil until the following spring.
- Seedlings emerge in thick stands in early spring beginning in March through April.
- Seeds can float and be moved along waterways and deposited on stream banks.
- Seed banks are viable in natural conditions from 18 months.
Control
- Small infestations can be effectively hand-pulled or dug up.
Chemical Control
Aminopyralid
- Treat in spring when plants are actively growing; summer before flowering.
- Many desirable plants can be seriously injured or killed; non-ionic surfactant at 1-2 quarts per 100 gallons will help enhance control under adverse conditions.
- Do not apply near the root zone of desirable trees.
- Do not compost plant material that has been sprayed by this product.
- Do not use manure from fields that have been sprayed with this product
- Do not apply near water.
Triclopyr + 2,4-D
- Treat in spring when plants are actively growing; summer before flowering.
- Repeat application for two years to control seedlings; avoid drift to sensitive crops; do not apply near water.
Glyphosate
- Treat in spring when plants are actively growing; summer before flowering.
- Spray complete, uniform coverage but not to the point of runoff.
- Dust on plants may reduce effectiveness.
- Glyphosate is nonselective, it inures or kills any vegetation it contacts.
- Do not apply near water.
Triclopyr Ester / Triclopyr Amine
- Treat in spring when plants are actively growing; summer before flowering.
- Spray complete uniform coverage.
- Dust on plants may reduce effectiveness.
- Garlon products are registered for range & pastures, non-crop areas, rights-of-way, industrial sites, and forestry sites.
- Do not apply near water.