Guidance on use of rainwater tanks

Dangerous plants

Page last updated: March 2011

Most plants are harmless but there are some plants in Australian gardens that produce toxins. Examples include:

  • fruits of the nightshade family such as Solanum rantonnetii and Solanum nigrum
  • the common oleander (Nerium oleander) and yellow oleanders (Thevetia peruviana)
  • lantanas such as Lantana camara and Lantana montevidensis
  • flowers and berries of white cedar (Melia azadirach var ‘australasica')
  • wintersweet (Acokanthera oblongifolia).
Most of these plants are low-growing and would be unlikely to affect above-ground tanks. In addition, there is little evidence of poisoning from plant material in rainwater tanks. However, there are anecdotal reports that flowers of the white cedar falling into tanks can cause diarrhoea (Campbell 2001).

As a general rule, roof catchments should be kept clear of overhanging tree branches and vegetation, and leaf filters should protect inlets to rainwater tanks. These practices will minimise the risk from plants.

Further advice on the potential toxicity of plants could be sought from local nurseries or operators of botanic gardens.