Plant of the Month - October - Himalayan Balsam


Tara O'Brien is an illustrator from Dublin. She graduated from the Dublin Institute of Technology in 2013 with an honours degree in Visual Communications. Her personal work has a focus on diverse representations of people, body politics and mental health. You can mostly find her drawing away while hanging out with her dog Frank.

Why did we pick it?

It's not just cultivated plants that are under threat from plant health issues: wild plants and ecosystems are also at risk. Himalayan balsam is a garden plant that escaped from captivity in Europe and North America. It's spread all over the UK along riverbanks, where its dense thickets outcompete native species: it reduces native species diversity by 25% in areas where it forms monocultures. The UK Environment Agency have estimated it would cost between £150-300 million to eradicate Himalayan balsam from the UK. As climate change progresses, it's likely to spread further north - but some wild plants are set to lose out from warmer temperatures and shrink their ranges. This month, we'll explore the plant health threats facing wild plants, and how research is helping monitor and control them.

Himalayan Balsam extras
Himalayan balsam is a rapidly-spreading invasive weed that outcompetes native British wildflowers. This project experimented with using a natural pathogenic rust fungus that exclusively attacks Himalayan balsam in its native range to control its population - raising questions about the responsible use of plant diseases to control unwanted species. The rust has been trialled at several locations in England and Wales.
NERC-funded study to monitor extinction risks to British flora: as part of this they DNA barcoded the entire floral diversity of Wales. This was to compare current genetic diversity with samples from 100 year-old herbarium samples, to help with conservation