Himalayan Balsam
(Impatiens glandulifera)
What is it?
Himalayan Balsam is a large, flowering annual plant that spreads via seed. The plant completes its entire lifecycle in one year and dies back in the Winter. It forms very extensive, dense and tall (up to 3 metres) clumps and utilises a unique form of seed dispersal where the seed pods 'explode' sending seeds as far as 7 metres from the parent plant. This form of seed dispersal ensures that the plant is commonly seen in these large groupings. If located close to a stream or river, the seeds can easily enter the river system and be transported downstream where new colonies can establish themselves.
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As a highly invasive plant species, Himalayan Balsam outcompetes native flora preventing their growth. When the plant dies back in the Winter, it leaves areas exposed to the effects of our harsh Winter climate and if the area is a riverbank for example, this can leave the riverbank exposed where higher river water levels can erode and destabilise the banks, undermining them.
What does it look like?
In Spring, the characteristic lance shaped or elliptical, serrated edged leaves begin to appear while the stems are green with a red tinge or linear streak along them. Leaves will also form from the individual nodes on the stem and will repeat this pattern as the plant grows taller. The stems themselves are hexagonal in shape which further helps in their identification. From mid Summer till early October the plant will flower pink / purple trumpet shaped blooms and the seed pods can begin to form from May onwards.