Water celery (Apium nodiflorum also known as Heloscadium nodiflorum) is native to Europe, northern Africa and western Asia. In New Zealand, it has spread through the North Island and is now becoming established in the Nelson region. It is a bright green spreading plant that grows easily from seed and pieces of root detached from the main plant.
Water celery infestation can affect infrastructure and native habitats. A stream choked with water celery can increase the size and frequency of flood events, and it forms dense mats that block sunlight and de-oxygenate the water, smothering our local flora, trapping sediment and reducing habitat for stream life.
Council is running a trial to control water celery in Orphanage Stream, Stoke, in March 2021.