Himalayan balsam (Impatiens glandulifera) is a native of the western Himalayas. Introduced to Britain in 1839 as a garden plant, it escaped and rapidly colonised river banks and other damp habitats*.
Most non-native species in London are not a cause for concern, but some invasive species can threaten biodiversity. Himalayan balsam thickets can crowd out other riverside flora.
The London Invasive Species Initiative (LISI) classify it as a ‘category 3 species’. This includes species of high impact or concern which are widespread in London and require concerted, coordinated and extensive action to control/eradicate. LISI categorisations are stored in GiGL’s data holdings.
Find out more about the partnership work of LISI here.
*from Managing Invasive Non-Native Plants, Environment Agency, 2010
Photo: Himalayan Balsam by Katherine Banham-Hall
December 2011