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Introduction
Policeman's helmet is an introduced summer annual that is native to the Himalayas, but has spread around the world since seeds were first sent from the Himalayas to KEW gardens in England in 1839. In North America it is found in the USA, primarily along the Pacific Coast and in the New England States (CA, CT, ID, MA, ME, MI, MT, NY, OR, VT, WA) and in Canada it is found in eight provinces (BC, MB, NB, NF, NS, ON, PE, QC) (USDA 2010). In British Columbia, it is found primarily in the southern part of the province, around Victoria, in the Fraser Valley, and in southeastern BC
Policeman's helmet is an easily identified species of Impatiens, 0.6 to 2.0 m in height, which produces distinctive white to pink, purple-spotted flowers with short recurved spurs. Flowering occurs from July to September. It can form thick homogeneous stands in moist shady spots along creeks, riverbanks and sloughs and in open sunny ditches. It produces abundant seed in seed capsules that explode when ripe allowing near dispersal and thick growth. The earliest collection record for this species in the UBC Herbarium is 1937, when it was collected at Still Creek, BC by John Eastman.
"[Policeman's helmet's] high reproductive rate, early germination, propensity for establishing thick stands, rich nectar production, hardiness, and habitat tolerance and plasticity have allowed it to spread rapidly, dominate landscapes, and compete with and displace native plant species." (Global Invasives Database 2010).
Species Information
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expanded illustration for this species.
1. Pouched sepals not spurred......................................I. ecalcarata
1. Pouched sepals spurred.
2. Leaves opposite or whorled (at least some of them), finely saw-toothed; flowers blue to purple or purplish-pink or sometimes white............................ I. glandulifera
2. Leaves alternate, coarsely saw-toothed; flowers orange or yellowish.
3. Spurs of the sepals straight, directed backward.......................................I. parviflora
3. Spurs of the sepals curved or hooked.
4. Flowers less than 2 cm long, without spots..........................I. aurella
4. Flowers more than 2 cm long, spotted, mottled or sparingly flecked.
5. Flowers orange, brown-spotted, or -mottled.........................I. capensis
5. Flowers yellow, sparingly flecked with brownish purple........................I. noli-tangere
Habitat / Range
Moist to mesic streambanks, meadows, roadsides and waste places in the lowland and steppe zones; infrequent in the lower Fraser Valley and extreme SC BC; introduced from Asia.
A combination of factors including a high reproductive rate, aggressive seed dispersal, early germination, and high nectar production which attracts pollinators allows this species to out-compete and displace native species. It is very attractive to pollinators (Bartomeus et al. 2010). For further information about control of this species, visit the Great Vancouver Invasive Plant Council web site.
References:
Bartomeus, Ignasi, Montserrat Vilà and Ingolf Steffan-Dewenter. 2010. Combined effects of Impatiens glandulifera invasion and landscape structure on native plant pollination. Journal of Ecology 98 (2): 440 - 450.
Ecology
Ecological Framework for Impatiens glandulifera
The table below shows the species-specific information calculated from original data (BEC database) provided by the BC Ministry of Forests and Range. (Updated August, 2013)
