Hydrocleys nymphoides (Humb. & Bonpl. ex Willd.) Buchenau: first record of naturalisation in South Africa

Hydrocleys nymphoides (water poppy), an aquatic plant native to South America, has been recorded as invasive on several continents (Europe, Australia and Asia). Here we report on the first known naturalized population in South Africa, in a dam in the KwaZulu-Natal (KZN) Midlands region, near the town of Howick. This population, first detected and identified in 2009, had by the end of the 2013 summer season occupied 1.8ha (30% of the dam). Surveys of 34 surrounding water bodies during the period between 2012 and 2013 did not result in detection of any new populations. The only other population (0.1 ha) was recorded growing in cultivation at the Durban Botanic Gardens. This note reports on the history of H. nymphoides in South Africa, details its current and potential distribution, looks at the risk it poses, and outlines plans for nation-wide eradication.