above sea level. In Europe the plant was first introduced into the United Kingdom by Dr John Forbes Royle, professor of medicine at King's College, London who became Superintendent of the Botanic Gardens, Saharanpur, India. It has now become naturalized and widespread across riverbanks. Presently it can be found almost everywhere across the continent. In North America it has been found in the Canadian provinces of British Columbia, Manitoba, Ontario, Quebec, Nova Scotia, New Brunswick, Prince Edward Island and Newfoundland. In the United States it is found on both the east and west coast, seemingly restricted to northern latitudes. In New Zealand it is sometimes found growing wild along riverbanks and wetlands. Invasive species Himalayan balsam is sometimes cultivated for its flowers. It is now widely established in other parts of the world (such as the British Isles and North America), in some cases becoming a weed. Its aggressive seed dispersal, coupled with high nectar production which attracts pollinators, often allows it to out-compete native plants. Himalayan balsam also promotes river bank erosion due to the plant dying back over winter, leaving the bank unprotected from flooding. Invasive Himalayan balsam can also adversely affect indigenous species by attracting pollinators (e.g. insects) at the expense of indigenous species. It is considered a "prohibited noxious weed" under the Alberta Weed Control Act 2010. In the UK, the plant was first introduced in 1839, at the same time as giant hogweed and Japanese knotweed. These plants were all promoted at the time as having the virtues of "herculean proportions" and "splendid invasiveness" which meant that ordinary people could buy them for the cost of a packet of seeds to rival the expensive orchids grown in the greenhouses of the rich. Within ten years, however, Himalayan balsam had escaped from the confines of cultivation and begun to spread along the river systems of England. It has now spread across most of the UK, and some local wildlife trusts organise "balsam bashing" events to help control the plant. However, a study by Hejda & Pyšek (2006) concluded that, in some circumstances, such efforts may cause more harm than good. Destroying riparian stands of Himalayan balsam can open up the habitat for more aggressive invasive plants such as Japanese knotweed and aid in seed dispersal by dropped seeds sticking to shoes. Riparian habitat is suboptimal for I. glandulifera, and spring or autumn flooding destroys seeds and