Invasive Species – Himalayan Balsam

Himalayan Balsam (Impatiens Glandulifera) is a relative of the “busy lizzy” but reaches well over head height and is a major weed problem. It is native to the western Himalayas and in the early 1800’s was introduced to many parts of Europe as a garden ornamental, it has since become an invasive plant as it grows rapidly and spreads quickly, smothering other vegetation as it goes.
Himalayan Balsam is often found in damp soil areas such as along river banks where it forms continuous stands, it can also be found in damp woodland.
Due to its rapid growth it shades out most of our native species and can leave river banks bare and exposed to erosion in the winter time.
Himalayan Balsam is a tall growing annual that can reach 2-3 metres in height, it has dark green leaves with serrated edges and a hollow stem, nearer the base of the plant Himalayan Balsam can often have red roots extending from the stem down toward the ground.
Between June and October it produces clusters of purplish pink helmet shaped flowers. The flowers are followed by seed pods that open explosively when ripe. Each plant can produce up to 800 seeds.
Many seeds drop into the water and contaminate land and riverbanks downstream, but because of the explosive nature of its seed release, seeds can be projected up to 4 metres away which means that it can spread upstream too.
It produces a lot of pollen over a prolonged season and is very attractive to pollinating insects. There is concern that its presence may therefore result in decreased pollination for other native plants.