Invasive Species
FOUND AROUND THE RIVER
HIMALAYAN BALSAM
Himalayan Balsam is an annual herb with stout succulent hollow stems which grow up to 2.5m. Its leaves are opposite or in whorls of 3 to 5, and it has a helmeted flower which is deep purplish-pink to white, and gives off a strong balsam smell. The plant is well established and extremely invasive, likes moist and semi-shaded damp places, particularly along the banks of slow-moving waterbodies, where it forms extensive monoculture stands to the exclusion of other plants. It mainly spreads via its floating seeds, which are dispersed by its explosive fruit capsule, with each plant capable of ejecting up to 800 seeds for a distance up to 7m. In addition, its attraction to pollinating insects could be to the detriment of our native plant species.
WHAT TO LOOK OUT FOR:
Himalayan Balsam is a large plant, normally reaching 1 to 2 metres in height, although in some cases it can grow as tall as 2.5 metres.
The serrated leaves grow along the stem joints either in pairs or whorls of three.
The green leaves are long and pointed and typically around 5 to 8 cm in length.
You will also note the plant’s visible seed pods which explode when touched.
The stems are green in the autumn and turn red towards the end of the year.
Between June and October, Himalayan Balsam produces clusters of white, pink and purple flowers with five petals giving it a hooded appearance.
The fruit capsules have an explosive opening action, firing seeds in all directions away from the plant.
Initially, the seeds are brown and turn black as they mature.