American Policeman's Helmet Gardens in Canada, Mexico, the United States

Summary: American policeman's helmet gardens in Canada, Mexico and the United States tame an introduced beauty designated a weed in one province and in three states.

Policeman's helmet (Impatiens glandulifera) blooms from June to October in North American gardens; closeup of policeman's helmet flowers, fruits, leaves and stem; Rosemont neighborhood, southeastern Portland, southern Maine: InAweOfGod'sCreation, CC BY 2.0, via Flickr

American policeman's helmet gardens are more of a joy indoors than outdoors since the annual in the Balsaminaceae family of jewelweeds and touch-me-nots assumes weed status in Canada and the United States.

Legislation in the Canadian province of Alberta and in the United States states of Connecticut, Oregon and Washington brings policeman's helmet weed status for threatening species diversity. Prolific seed production in forests and in moist, open areas causes the annual, introduced as garden ornamentals for North Americans by 1970, to checkmate native vegetation. The common names Himalayan impatiens and Indian balsam describe Asian origins while ornamental jewelweed, policeman's helmet and purple jewelweed designate the bloom and touch-me-not the fruit.

Policeman's helmet respectively epitomizes desirable and undesirable candidates for enduring urban landscape stress by tolerating high soil moisture and through using multiple propagation and survival methods.

Containers for indoor American policeman's helmet gardens favor Impatiens glandulifera's (impatient gland-bearer) frost-sensitive life cycles and force the partially shade-tolerant introduction into less aggressively invasive behavior. They gather the adventitious roots that grow near the soil surface and the shallow roots that grow 6 inches (15.24 centimeters) downward into a growth-limiting space.

Policeman's helmet seedlings have their roots 12 days after germination of floating seeds underwater and of soil-bound seeds any time within two years of having been sown. Seedling cotyledons, oval-like or rounded, increase rapidly once photosynthesis impels carbohydrates and hormones multi-directionally four weeks after germination and roots introduce dissolved hormones and nutrients upward. High soil moisture jumpstarts seedlings into mature policeman's helmets with angular, green, hairless, hollow, purple- or red-tinged, succulent, 3.28- to 9.84-foot- (1- to 3-meter-) tall stems.

The egg-shaped or oblong foliage knows opposite arrangements, or whorls of three to four leaves, around stalks 1.18 to 1.38 inches (3 to 3.5 centimeters) long. It quickly leafs out to 1.97- to 9.06-inch (5- to 23-centimeter) lengths and to 0.39- to 2.76-inch (1- to 7-centimeter) widths.

Twenty-plus teeth-like patterns mark each side of regular leaf margins, but not those of elliptical, lance-shaped or oval 0.28- to 0.32-inch- (7- to 8-millimeter-) long bracts. Floral, modified leaves called bracts nestle around two- to 14-flowered floral clusters, called inflorescences, atop axillary stalks as much as 3.54 inches (9 centimeters) in length. Each irregular, pink, purple or white 0.79- to 1.38-inch- (2- to 3.5-centimeter-) long flower offers one nonfused of three sepals and three nonfused of five petals.

All policeman's helmet flowers possess one pistil, one 0.19- to 0.24-inch- (5- to 6-millimeter-) long spur on the flower of two fused sepals and five stamens.

The first black to brown, globe-shaped, rough, 0.0787- to 0.1968-inch (2- to 5-millimeter) seeds quit their four- to 16-seeded fruits 13 weeks after the first flowering. Club-shaped, exploding, nodding, 0.55- to 1.18-inch- (14- to 30-millimeter-) long, 0.16- to 0.32-inch- (4- to 8-millimeter-) wide fruit capsules release seeds over a 22.96-foot (7-meter) radius. American policeman's helmet gardens sometimes share indoor releases with fellow Impatiens plants not yet designated weeds: Africa's balsam, Asia's balsam and North America's pale touch-me-not annuals.

Indoor containers tease policeman's helmets, roots and shoots into tame houseplants even though gardening in the time of exploding capsules turns into a run for cover.

vivid roots of policeman's helmet (Impatiens glandulifera): Peter Valic, CC BY SA 3.0, via Wikimedia Commons

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

closeup of policeman's helmet (Impatiens glandulifera) flowers, fruits, leaves and stem; Rosemont neighborhood, southeastern Portland, southern Maine: InAweOfGod'sCreation, CC BY 2.0, via Flickr @ https://www.flickr.com/photos/nhoulihan/3764119636/

vivid roots of policeman's helmet (Impatiens glandulifera): Peter Valic, CC BY SA 3.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Impatiens-glandulifera-2012-07-PV.JPG

For further information:

Dickinson, Richard; France Royer. 2014. Weeds of North America. Chicago IL; London, England: The University of Chicago Press.

"Impatiens glandulifera Royle." Tropicos® > Name Search.
Available @ http://www.tropicos.org/Name/3100049

Royle, J. (John) Forbes. 1839. "I. glandulifera." Illustrations of the Botany and Other Branches of the Natural History of the Himalayan Mountains, and of the Flora of Cashmere. Vol. I: 151. London, England: William H. Allen and Co.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/2912704

Royle, J. (John) Forbes. 1839. "2. Impatiens glandulifera." Illustrations of the Botany and Other Branches of the Natural History of the Himalayan Mountains, and of the Flora of Cashmere. Vol. II - Plates: 28. London, England: William H. Allen and Co.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/2913380