News and Tips

Azolla identification

Azolla (Azolla filiculoides), or fairy fern, is an attractive weed with fern-like fronds which turn a reddish colour in autumn.  However, it is extremely invasive and was banned from sale in 2014.  Once introduced to a garden pond, or our wider waterways, it can spread rapidly forming a thick mat which blocks out light and reduces oxygen availability as well as giving the appearance of a solid surface which animals, or children, may mistake for dry land.
The only solution currently for controlling Azolla is a weevil which is available from the Commonwealth research organisation CABI via their website at
The weed just visible on the iris in this photograph is duckweed (Lemna minor).  This can develop in the same way as Azolla causing similar problems and can be treated with Ecopond Duckweed Control which will, with regular dosing, prevent re-growth and spread.  For more information on preventing and treating Duckweed see our separate Duckweed information page.