I have stumbled upon this interesting article, it sounds very interesting, I wonder how well it really works at repelling insects, and what insects, free fertilizer sounds great too
Intresting water fern. Nice find 
i am however worried it might become invasive. And don’t see obvious advantages that compensate for this disadvantage.
clover or a lot of native plants are also nitrogen fixers. Virtually the whole legume (including the foodplant versions are)
it’s not the sharpest photo. but you can see the little balls. Thats where the clover in symbiose with a soil bacteria has fixed nitrogen.
This was a white clover, perennial. sowed late in the last year. i think it was oktober. photo was taken a few days ago
They can technically be grown in water tubs or pots that is how people stop some of the most invasive plants from being invasive, for me it was the insect repelling that got my attention the most. I think that it would be interesting to experiment, in some states growing any Azolla is illegal, yet not in the state I live because Azolla is a native plant in some parts of our state, just not this version of Azolla.
are you not worried that birds “visiting” your tubs might spread it? since it’s such a smal viable plant?
Right now I am just brain storming ideas, I was thinking about using a very fine net over them to keep mosquitos from laying eggs in the water, that would also keep birds from taking pieces away.
ah, sounds like your thinking it trough 
Sorry if my first points where overly negative or “rained on your parade”
It’s just that if seen what invasive plants can do. And especially those that multiply fast and can cover water surfaces can be especially nasty. So seeing that fern made alarm bells ring inside my head.
If there is a native version or family member of it around you. Might it be a good idea to first try that one out? first experiment with the less dangerous version.
The native kind, they grow in the wetter parts of our state. I have not been to any of those parts of the state yet, there are crocodiles there too. It will be my first time being close to crocodiles in person. It really depends on when I could get to that part of the state if I experiment with it first. Maybe next year I could go there.
