Blanketweed often feels like a never-ending battle for pond keepers. It is unsightly and if left to go out of control can be harmful to pond inhabitants with Frogs becoming tangled when going up for breath or Sturgeons getting caught up often leading to death. Unfortunately, blanketweed seems to come and go as it pleases and can be a long-term fight to get rid of. However, going back to basics, blanketweed is simply a plant and a plant needs two things to grow; nutrients which is good supply in a pond from Fish waste and other organic matter and secondly light which the Sun gives a lot of. In a perfect ideal world if you can reduce the number of hours your pond receives sunlight; in the form of a pergola, cover etc. would massively help against the growth of blanketweed. But for more practical solutions testing the water for parameters such as nitrates and phosphates will give you a good idea of where to go with the problem. If these levels are too high, it’s essentially an open tap of nutrients feeding the blanketweed. So, a suggestion would be to firstly carry out a series of water changes to reduce the levels, secondly you can look at the market of pond products that help in reducing these parameters such as phosphate/nitrate removing blocks, chemicals and granules. You can also purchase a blanketweed control treatment from a pond shop that comes in the form of a white powder which you mix with some pond water and dose across the pond, often requiring numerous ongoing doses but usually see good results.
Another option but should only be considered for the larger ponds would be Grass Carp. This is a species of Carp that attains a large maximum adult size of 120cm so before jumping to this option consider whether you have a pond large enough for this Fish and if you want to house one long term as it’s a long-lived specie. If your pond would make a good home for a Grass Carp then these are a fantastic option to control your blanketweed as they have a known taste for it, be warned though blanketweed would not be the only thing on the menu for these gentle giants, anything green and leafy will be lunch including your beautiful pond Lily!
