What’s the problem with Himalayan balsam?

What’s the problem with Himalayan balsam?

Himalayan balsam (HB) is a widespread and damaging invasive non-native species (INNS) which grows rapidly each summer in dense monoculture stands, especially along riverbanks, and shades out deeper-rooted native species before dying back in winter. Bare soil is left without perennial root structures to stop soil from being eroded and dumped into rivers as silt (one recent study suggests a rate of 10 tonnes per km per year). This smothers gravels, invertebrates and fish eggs, and threatens salmon and trout populations in particular.

HB infestations also cut off access for angling and other activities and worsen damage from other INNS (e.g. making riverbanks more vulnerable to collapse from signal crayfish tunnelling).

Look out for for further posts on DAA 2025 initiatives relating to Himalayan Balsam.