Control and eradication of Australian swamp stonecrop Crassula helmsii using herbicide and burial at two ponds at Mile Cross Marsh, Norfolk, England.
Crassula helmsii (Australian swamp stonecrop or New Zealand pygmyweed) was first recorded growing on Mile Cross Marsh in Norwich, Norfolk, UK before 2003. Previous management undertaken to prevent the spread of this plant across the site had been unsuccessful. A three-phase project was undertaken in 2012 to control C. helmsii on Mile Cross Marsh. The aim was to eradicate C. helmsii from two infected ponds and reduce the risk of plants spreading through the boundary onto Sweetbriar Marsh Site of Special Scientific Interest. The control programme included herbicide application and in situ burial due to the high level of pond infestation. The project successfully achieved its aim of eradicating C. helmsii from the infected ponds and preventing the further spread of C. helmsii on Mile Cross Marsh. However additional work will be required to fully eradicate the plant from the site.