By Kate Bradbury on 26/02/2010 16:23:36
(Hydrocotyle ranunculoides) parrot's feather (Myriophyllum aquaticum), New Zealand pigmyweed or Australian swamp stonecrop (Crassula helmsii), water primrose (Ludwigia grandiflora) and water fern, (Azolla filiculoides). If left unchecked, these non