Azolla: Supplemental Greens for Waterfowl

When I first read about Azolla as a supplemental source of greens for ducks in Carol Deppe’s book, The Resilient Gardener, I was immediately hooked. I searched out a source and got myself a little wad of the aquatic plant and placed it in a tub of water I had on my back patio. It turned out to be such a thrill both as a plant and as a great fodder for my ducks.

Azolla seems to go by many common names, all which describe its character very well: fairy fern, duckweed fern, fairy moss, pond fern, etc. There are about 7 species of Azolla worldwide – I chose Azolla caroliniana because it was easy to find and because it wasn’t hardy in my area.

I didn’t want a hardy Azolla, because like Duckweed, it can become invasive and be a big issue in ponds and other bodies of water. If you live in warmer regions of the country, you need to grow Azolla responsibly and not allow it to get into natural ponds. I live in New York state and unless I bring some in a bowl into my greenhouse in the fall, it will die completely once temperatures hit 20 degrees or below.

Azolla is very attractive – it gets about 1 inch high in full sun, is bright emerald green in color, and completely covers the entire water surface of any container it is in. It looks like a mat of thick little ferns floating on the water. In cooler weather or if it is grown in shade, it is a reddish color and grows more slowly. I use it in ornamental aquatic plantings to keep mosquitoes from breeding in the water. Larger honeybees can make good use of it – the Azolla can hold the weight of a honeybee, so they can safely land on it and honeybees are big enough to then reach the water surface to drink. It also helps keep the water clean; the tubs with the Azolla sit in the sun all summer long and never start to smell stagnant.

Azolla works so well with ducks and waterfowl. It makes a lot more bulk green plant matter than Duckweed and grows just as fast – a couple handfuls will cover a wading pool in a couple of weeks in midsummer. Azolla doubles its biomass every couple days. Throw a shovel of garden soil into the pool when you put the Azolla in – it grows much faster if it has a bit of soil in the water to work with.

I now have a set of 4 duck pools that I rotate. I let the ducks use one at a time as the Azolla grows over the pools in waiting. Ducks love Azolla – they gobble it down and have a true blast doing it. To ducks, nothing beats a floating salad! And the ducks look so great swimming in the floating ferns.

Azolla is actually a highly nutritious way to add diversity to waterfowl diets – it has 25-30% highly digestible protein, and it is rich in essential amino acids, vitamins, and minerals. Many farms have started using it to supplement young chickens and other fowl, as well as pigs and cows. There has been a lot of interest in Azolla recently as an organic and low cost nutrient-rich animal feed.