Also known as Australian Swamp-stonecrop, Pygmyweed arrived in the UK in 1911. Like parrot’s feather it was introduced as an oxygenating plant for ponds and wasn’t recognised as a serious threat until the 1970s. It reproduces from tiny stem fragments and can be submerged, emergent (at the edges of water bodies) or terrestrial, growing in and around ponds, lakes and slow moving water courses. Left to its own devices, it forms an impenetrable green mat, pushing out plant and animal species and damaging wetland habitats. Pigmyweed grows all year round and produces small white flowers from June to September.
Photo Credit GBNNSS