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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.

Photos

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.
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