Van der Loop, J.M.M., R. Beringen, R.S.E.W. J.L.C.H. van Valkenburg, H.H. van Kleef, M. Verhofstad & B. Odé (2019). Risk assessment of Australian swamp stonecrop (Crassula helmsii) in Europe FLORON report: 2019.064

This report describes a risk assessment of the alien species Australian swamp stonecrop (Crassula helmsii) (hereafter: Stonecrop) in Europe. The species is native to Australia and New Zealand but has been imported in many places in the world as ornamental species for aquaria and garden ponds. It is a small perennial species of water bodies and wetlands. The species is considered invasive in several European countries. The present risk assessment is based on a detailed risk inventory and supports national and international decision making on the management of Stonecrop. The available information and data were analysed and the risks were classified by a team of experts using the Harmonia+ protocol.