Himalayan Balsam: Tackling the pink invader

You might not have heard of Himalayan balsam before, but I’m sure you’ve seen it. It’s all over Snowdonia but is most commonly seen on the banks of rivers and lakes or in damp fields and meadows.

Once you get your eye in it’s reasonably easy to identify with its pink ‘police helmet’ flowers, lance-shaped leaves, and reddish stem. Himalayan balsam is an annual plant, meaning it grows to maturity, reproduces and then dies in a single year. You’ll first see the plants germinating between February and April, followed by rapid growth of foliage until mid-summer, by which time they may have grown up to three metres tall. This height makes Himalayan balsam the tallest annual plant in the UK. By June they start coming into flower, allowing them to be pollinated and subsequently produce their seed pods. Between the months of July and October an individual plant can produce up to 800 seeds, which can get fired up to 7 meters when the seed pods explode. These seeds fall to the ground but also find their way into watercourses, travelling downstream to germinate in new sites. The plants then die back after October, leaving their seeds dormant in the ground, ready to germinate the next February.

Why is Himalayan balsam such an issue in Snowdonia and the UK?

Himalayan balsam is an ecologically destructive invasive species first introduced by the Victorians as an ornamental garden plant. Its high fecundity, fast growth rate and wide seed dispersal allowed it to quickly establish itself and spread throughout the British countryside. As previously mentioned, Himalayan balsam is extremely fast-growing, meaning it outcompetes and shades out native plants. Himalayan balsam is also a good nectar source, meaning bees will often visit Himalayan balsam in preference to native plants. A reduction in pollination and shading out of native flora reduces the diversity of plants growing on the banks of affected rivers, lakes, and meadows. The reduction of native plant diversity and abundance may affect the functioning and stability of the delicate ecosystems of Snowdonia. Outcompeting of native plants has further consequences on riverbanks: Once the Himalayan balsam has died back in the winter the affected riverbanks are left bare of any native plants and their root systems, making the soil vulnerable to erosion.

Tackling the problem

There are a few ways to control Himalayan balsam, but Snowdonia Society will be removing it by uprooting the plant from the ground – luckily, they have very shallow roots so are reasonably easy to pull out by hand. The plants are then piled up and left to rot down on site. We never remove the uprooted plants from the site because this may spread seeds to other areas. We start pulling up balsam in April or May and continue to remove it until they start to seed. Each site will be visited multiple times during the season to make sure we don’t let any slip through the net!

We will also start pulling out balsam as far upstream as possible: Himalayan balsam often spreads down the river using the current of the water to transport seeds – meaning it can easily spread downstream but not so easily back upstream. By systematically working down the river it means areas we’ve already cleared are less likely to be repopulated by Himalayan balsam.

This year we’ll be working as part of the Carneddau Landscape Partnership to reduce the numbers of balsam in the Carneddau area. By tapping into local knowledge, wildlife record databases and our own surveys we have a better knowledge of where we need to target to eradicate balsam from the Carneddau.  We have a big task ahead of us to eradicate it from this area, but by working with other groups such as ‘Tregarth Balsam Bashers’ and ‘Friends of the Earth Conwy’, we’ll give it a good go!

We’ll need as much help as we can get from volunteers around Snowdonia to get the number of Himalayan balsam under control. It’s always a fun day in the sun; you’ll meet like-minded people, with a shared passion for wildlife and the outdoors. Volunteering is also a great way to build local connections and give back to the community. You’ll learn new skills; gain knowledge of local wildlife and work in beautiful places you wouldn’t usually visit.

If you’d like to get involved with any Himalayan balsam volunteer days, then please register on our volunteer sign up system My Impact. Additionally, you can also help the fight against the pesky pink flower by logging any areas of Himalayan balsam you see on the Cofnod invasive species map. This is a way of logging and mapping any sightings of invasive species.  All you need to do is make a note of the grid reference and enter it on the website.

Comments are closed.