Alien Invader Himalayan Balsam

Up to 2.5m tall with pretty pink flowers and an odd looking reddish stem, this plant has been taking over UK river beds and wetlands since its introduction in the 1800's. 

This summer I was introduced to the Himalayan Balsam through my work as a Conservation Volunteer at Staffordshire Wildlife Trust. One sunny Tuesday I was driven out to a wetland and a group of us spent the day clearing, what felt like miles and miles of this Invasive Alien Species! Easily removed, you just pull it up by the base of the stem and it pops out the soil along with all of the roots. The key trick to controlling this pesky plant is to remove it before it flowers, as soon as it does it explosively spreads its seeds.

As you can see from images above that I captured next to the River Sow in Stafford, this plant dominates all the river bank that it possibly can! Beerling and Perrins believe that it is able to successfully invade and outcompete all the other plants because of the large seed bank it germinates at the same time each year. This then suppresses the growth of other neighbouring species by taking up space, water and nutrients. In 1987, these same scientists performed experiments and showed that Himalayan Balsam is more tolerant to nutrient deprivation, making it more likely to survive compared to other plant species. They think this is possible due to the multiple branches off the main stem, allowing the plant to fill all possible gaps of aerial space it can. 

Spread of Himalayan Balsam: (a) 1900 (b) 1920 (c) 1940 (d) 1960

As soon as the Himalayan Balsam arrived from the Himalaya it began to spread very rapidly. The figure to the right was created by M. B Usher to show this. As you can see from 1900 onwards it began to take over almost all of the UK. Usher saw that it was mostly found along heavily polluted rivers which suggested it could only invade areas that were already disturbed and weakened by humans. This plant is then more able to successfully act as a Invasive Alien Species if native species have already been killed off. Linking back to last weeks blog post, it again takes multiple threats in order to lead to invasion caused extinctions!!






In 2015 The Telegraph released a gardening piece discussing the UK's top invasive plant species, the Himalayan Balsam being one of them. Click the link below to see if you recognise any of the other commonly Invasive Alien Species!

http://www.telegraph.co.uk/gardening/problem-solving/the-uk-s-most-invasive-plants// 

Not only is this annual plant found along river banks and waterways, I also spotted it this summer in Cannock Chase Forest, my local AONB but this time is was not directly next to a water source as you can see by my image below. Have you spotted any of this Invasive Alien Species near you? 

Click the link here to check out Staffordshire Wildlife Trust's homepage http://www.staffs-wildlife.org.uk