Is Duckweed Good for Ponds?

Duckweeds are one of my favourite, misunderstood and underappreciated pond plants there is. In the family Araceae it can provide so many benefits to a pond and I would argue no problem at all when properly maintained. It truly saddens me how disliked this plant is, so please allow me to present this plant in a new light.

Native species of duckweed:

• Common Duckweed - Lemna Minor

• Ivy leaved Duckweed - Lemna Treslea 

• Great Duckweed - Spirodela Polyrhiza

• Rootless Duckweed - Wollfia Arrhiza

• Fat Duckweed -- Lemna Gibba

Firstly, duckweed is one of the fastest growing plants and, given the right conditions, can double its mass every 24 hours, taking huge amounts of nutrients out of the pond. Thus, if your wildlife pond does not have a mechanical filter, it can work in tandem with other plants and bacteria in the pond to create a biological filter to process waste, keeping your pond clean and healthy.

Furthermore, using this method to filter your pond instead of a mechanical filter means maintenance becomes netting out excess duckweed and trimming plants rather than cleaning expensive filter systems and treatments. Speaking from a lot of experience, the former trumps the latter. With proper design, any pond can be biologically filtered.

Duckweeds also provide food and shelter for a wide variety of wildlife, which helps to improve diversity in the local environment. It is also so high in nutrients that it's grown commercially for fertiliser. So, all the removed duckweed is great for use in your garden.

It's also edible and very nutritious if you don't mind the bugs.

Finally, a quick word for Wolffia arrhiza, my favourite species of duckweed and possibly my favourite pond plant. As far as we know, it is the world's smallest flowering plant and is just incredible along the surface of a pond.