Dee day volunteers to clear Himalayan balsam
27 June 2014 Last updated at 09:56 BST
Volunteers are taking to the banks of the River Dee in north Wales to tackle an invasive plant that has colonised much of the river bank from Bala to Chester.
Himalayan balsam crowds out other plants, and can leave river banks exposed to erosion.
Lyn Byrne, the Dee invasive project officer at North Wales Wildlife Trust, told BBC Radio Wales' Mai Davies why it was such a problem.