Using only natural materials, we monitored a trial site at the Penarth Feeder to see whether this innovative method could be successful in the fight against Himalayan balsam.
Though it may look and sound appealing, Himalayan balsam can grow between 2-3m in height. Due to the large amount of seeds each plant produces, it can form dense areas of growth, crowding out native wildflowers and plants, and preventing them from getting the natural light and nutrients they need to survive.
Until now, chemicals and manual pulling have been the only ways to treat this problematic plant.
How was this trial eco-friendly?
Rather than relying on chemicals, this trial used only natural materials.
What did the trial involve?
To begin with, the Penarth Feeder was dredged, which involved removing silt from the bottom of the water.
This was already a positive action, as a build up of silt in our waterways can cause problems for native wildlife by de-oxygenating the water and clogging the gills of fish. It also makes it harder to navigate boats.
The collected silt was then placed on top of a biodegradable hessian matting above the Himalayan balsam seed bank, to snuff out the plant and prevent it from growing.
The next stage was then to hydroseed the bank with native wildflowers and grasses, to help encourage biodiversity back into the area.
What were the results?
After six months, we were delighted to see very limited regrowth of Himalayan balsam on the bank, and instead an appearance of a variety of native plant species.
This was in contrast with steeper areas of the bank that were left untreated, where Himalayan balsam is clearly visible.
The isolated regrowth of Himalayan balsam within the trial area was easily maintained by mowing and removal by hand.
How you can join the fight against invasive non-native species (INNS)
If you spend time on our canals and rivers, one of the most important things you can do is to remember to Check, Clean, Dry. These steps help stop the spread of harmful plants and animals to a new area, and should always be done before exiting a waterway, even if you are moving to another spot just a few miles away.
