Himalayan Balsam is now a common sight along many river banks in the UK. It is non-native and was imported as an ornamental plant to be used in people’s gardens. Unfortunately it did not stay within these gardens for long as it produces seed pods in late summer that can shoot its seeds great distances allowing it to disperse far and wide especially it the seeds can enter a water course.
This plant especially likes shaded moist areas so many river banks are prime spots for them and the running water allows their seeds to be deposited further downstream. This plant also seems to out compete other plants and dominate in the areas it is found, which is not only a problem in terms of reducing plant diversity but this plant completely dies back to nothing after the first frost leaving the banks bare and this increases the amount of sediment that is washed into the channel during heavy rainfall.
Another problem with this plant is that pollinating insects can’t get enough of it, so I guess you are thinking surely that’s a good thing when pollinating insects, especially as some species of bee are on the declining. Yes it is good news for the individual insects but bad news for other native plants that rely on these insects for pollination as the bees will select Himalayan Balsam over other native plants which increases the problem of this plant dominating an area.
We are hopeful that the sight of Himalayan Balsam dominating the banks of the Roman River is a thing of the past after a successful project to eradicate this plant is showing positive signs. This project began in autumn 2011 when the Roman River was surveyed to pinpoint and record the location of this plant along the whole stretch. This was achieved by a surveyor walking the whole river and using a GPS unit to record the grid references of not only stands of plants but also individual plants.
Once the data was collected the locations were mapped so the full extent of the problem could be seen and decisions could be made on how to tackle it. The next step had to wait until the plant had regrown and were visible once more but we had to make sure we tackled them before they were ready to seed as we wanted to remove them before we ran the risk of releasing the seed and allowing the plant to return the following year. Once found they are easy to remove as they have very shallow roots and can be easily pulled roots and all. We attempted to remove every single plant including tiny little seedlings that were scattered everywhere. Although the plants were easy to pull it was hard work as the weather was extremely humid but we had to work in long trousers and long sleeved tops as we were working amongst sting nettles in most instances. Once removed we left the plants in-situ, once again to avoid spreading the problem as removing them from site could have spreading this plant to other areas. The removed plants were checking a few days later to ensure they were dying off and not re-growing. This was done for every plant and stand of plants identified during the surveys in the previous autumn and was achieved with help of Essex Wildlife Trust staff, volunteers and school groups who came along to help us out. We ended the summer of 2012 optimist that our efforts had been worthwhile, and then in the summer of 2013 we ventured out again to see what we would find and were delighted to discover that almost no plants Himalayan Balsam were found. In places where the area was dominated by Himalayan Balsam we had to search very hard to find any and in some areas this plant was complete absent. We are now hopeful that with a bit more work next year we may be able to completely eliminate this plant from this river and it also gives us hope that we can achieve similar results along other rivers too.
If you have Himalayan Balsam in your garden then please consider removing it. We know it is a very pretty plant and that it is great for bees but once it gets out into the wider environment then it can cause major problems and it is very difficult and expensive to control!
