| Stone mulch exists
| | Inorganic mulch materials can be of particular value applied in areas with rapid water flow, or extended ponding times i.e. around [[inlets]] and in the the centre of recessed, bowl shaped or [[swale]] practices. Inorganic mulches resist movement from flowing water and do not float. Applying a thin layer of inrgonaic mulch over the top of wood based mulch has been shown to reduce migration of the underlying layer by around 25% <ref>Simcock, R and Dando, J. 2013. Mulch specification for stormwater bioretention devices. Prepared by Landcare Research New Zealand Ltd for Auckland Council. Auckland Council technical report, TR2013/056 </ref>. |
| <ref>Simcock, R and Dando, J. 2013. Mulch specification for stormwater bioretention devices. Prepared by Landcare Research New Zealand Ltd for Auckland Council. Auckland Council technical report, TR2013/056 </ref> | | Inorganic mulches which may be available locally, include: |